JP2004189177A - Driving operation assisting device for vehicle and vehicle equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving operation assisting device for a vehicle capable of preventing a driver from having sense of incongruity when a preceding vehicle is not detected. <P>SOLUTION: This driving operation assisting device for the vehicle has obstacle detection means 10, 20 for detecting an obstacle existent around own vehicle, a risk potential calculation means 50 for calculating risk potential for the obstacle of own vehicle, an operation reaction force determining means 50 for determining operation reaction force generated in a vehicle operation equipment in accordance with change pattern set in advance, and an operation reaction force generation means 50 for generating operation reaction force in the vehicle operation equipment based on a signal from the operation reaction force determining means 50. It is provided with an operation reaction force compensation means 50 for compensating change pattern when the obstacle detected by the obstacle detection means 10, 20 becomes out of object. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【数１４】

【００３５】
同様に、レーダスキャン範囲の左側境界と自車線右端との交点（ｘ２，ｙ２）は、（式６）と、（式１２）とを連立して演算することにより、以下の（式１５）（式１６）のように表される。
【数１５】

【数１６】

【００３６】
これらから、曲線路の場合の自車線内の検知可能領域を以下のように設定する。は、
（１）ｙ２≧ｙ≧ｙ１、かつｙmax≧ｙのとき、すなわち障害物と自車両との距離ｙがｙ１以上かつｙ２以下、かつレーザレーダ１０の最長検知距離ｙmax以下の場合
【数１７】
√｛（Ｒ＋Ｄ）²−ｙ²｝−Ｒ≧ｘ≧−ｙ・tanθ（式１７）
【００３７】
（２）ｙ１＞ｙ（＞０）のとき、すなわち障害物と自車両との距離ｙがｙ１よりも小さい場合
【数１８】
ｙ・tanθ≧ｘ≧−ｙ・tanθ （式１８）
なお、右カーブの場合も左カーブの場合と同様にして、自車線内の検知可能領域を算出できる。
【００３８】
なお、ここでは車速Ｖと操舵角STRとから道路形状を推定しているが、これに限らず、例えば前方風景を撮影したカメラ画像を画像処理して白線を認識したり、ナビゲーションシステムから得られた道路情報を元に道路形状を推定することもできる。
ステップＳ５００で検知可能領域を算出した後、図４のステップＳ６００に進む。
【００３９】
ステップＳ６００では、ステップＳ２００で認識された現在の障害物の自車両に対する相対位置やその移動方向・移動速度と、ステップＳ５００で算出された自車線内の検知可能領域とから、障害物が自車線内の検知可能領域をどのように移動しているかを推定する。ステップＳ６００で行う処理を、図８のフローチャートを用いて説明する。
【００４０】
ステップＳ６０１では、レーザレーダ１０により前方障害物を検知しているか否かを判断する。ステップＳ６０１が肯定判定されると、ステップＳ６０２へ進む。
【００４１】
ステップＳ６０２では、前方障害物が遠方に移動中か否かを判定する。ステップＳ６０２が肯定判定されると、ステップＳ６０３に進み、障害物状態フラグflgSTATEに１をセットする。ステップＳ６０２が否定判定されると、ステップＳ６０４に進む。
【００４２】
ステップＳ６０４では、前方障害物が隣接車線に移動中か否かを判定する。ステップＳ６０４が肯定判定されると、ステップＳ６０５に進み、障害物状態フラグflgSTATEに２をセットして終了する。ステップＳ６０４が否定判定されると、ステップＳ６０６に進む。
【００４３】
ステップＳ６０６では、前方障害物が自車線内検知可能領域内から検知可能領域外に移動中か否かを判定する。ステップＳ６０６が肯定判定されると、ステップＳ６０７に進み、障害物状態フラグflgSTATEに３をセットして終了する。ステップＳ６０６が否定判定されると、ステップＳ６０８に進み、障害物状態フラグflgSTATEに４をセットして終了する。
【００４４】
ステップＳ６０１が否定判定されて前方障害物を検知していない場合は、ステップＳ６０９に進む。ステップＳ６０９では、前回周期で算出したアクセルペダル反力制御指令補正値ＦＡout（Ｓ７００で算出する）が０か否かを判定する。アクセルペダル反力制御指令補正値ＦＡoutについては後述する。ステップＳ６０９が肯定判定されると、ステップＳ６１０に進み、障害物状態フラグflgSTATEを０にクリアして終了する。一方、ステップＳ６０９が否定判定され、反力指令補正値ＦＡoutが０でない場合は、前回周期でセットした障害物状態フラグflgSTATEをそのまま使用する。
【００４５】
上述したステップＳ６０２、ステップＳ６０４、およびステップＳ６０６における、前方障害物がそれぞれ遠方、隣接車線、自車線内検知可能領域外に移動中であるか否かの判定は、所定時間Ｔ０（例えばＴ０＝１[sec]）後の障害物の位置に基づいて行うことができる。これらの判定方法を、道路形状別に図９および図１０を用いて説明する。図９は自車線が直線路である場合を示し、図１０は自車線が曲線路である場合を示していす。ここで、前方障害物の位置を（ｘ（０）、ｙ（０））、相対速度を（ｄｘ、ｄｙ）とする。
【００４６】
《直線路の場合》
まず、図９を用いて直線路の場合に障害物がどの方向へ移動しているかを判定する方法を説明する。
所定時間Ｔ０後の、前方障害物の位置（ｘ（Ｔ０）、ｙ（Ｔ０））は、（式１９）（式２０）のように表される。
【数１９】
ｘ（Ｔ０）＝ｘ（０）＋Ｔ０・ｄｘ （式１９）
【数２０】
ｙ（Ｔ０）＝ｙ（０）＋Ｔ０・ｄｙ （式２０）
【００４７】
（ａ）遠方へ移動中（flgSTATE=1）
【数２１】
ｄｙ＞０ （式２１）
【数２２】
ｙ（Ｔ０）≧ｙmax （式２２）
前方障害物の走行状態が（式２１）および（式２２）を満たす場合、すなわち前方障害物の車速が自車速よりも大きく、所定時間Ｔ０後の縦方向相対距離ｙ（Ｔ０）がレーザレーダ１０の最大検知距離ｙmaxよりも大きい場合、前方障害物は遠方に移動中であると判断することができる。
【００４８】
（ｂ）隣接車線へ移動中（flgSTATE=2）
前方障害物の移動経路は、以下の（式２３）で示される。
【数２３】
ｙ＝ｄｙ／ｄｘ・｛ｘ−ｘ（０）｝＋ｙ（０）（式２３）
（式２３）によって算出される前方障害物の移動経路を用いて、前方障害物が自車線から隣接車線へ移動しているか否かを判断する。
【００４９】
・ｄｘ＞０のとき、すなわち前方障害物が相対的に車両右方向へ移動している場合
【数２４】
ｙ１＜ｄｙ／ｄｘ・｛ｘ１−ｘ（０）｝＋ｙ（０）（式２４）
【数２５】
ｘ（Ｔ０）≧ｘ１ （式２５）
前方障害物の走行状態が（式２４）および（式２５）を満たす場合、すなわち前方障害物との縦方向相対距離がｙ１より大きく、所定時間Ｔ０後の横方向相対距離ｘ（Ｔ０）がｘ１以上の場合、前方障害物は右車線に移動中であると判断することができる。
【００５０】
・ｄｘ＜０のとき、すなわち前方障害物が相対的に車両左方向に移動している場合
【数２６】
ｙ２＜ｄｙ／ｄｘ・｛ｘ２−ｘ（０）｝＋ｙ（０）（式２６）
【数２７】
ｘ（Ｔ０）≦ｘ２ （式２７）
前方障害物の走行状態が（式２６）および（式２７）を満たす場合、すなわち前方障害物との縦方向相対距離がｙ２より大きく、所定時間Ｔ０後の横方向相対距離ｘ（Ｔ０）がｘ２以下の場合、前方障害物は左車線に移動中であると判断することができる。
【００５１】
（ｃ）自車線内検知可能領域外に移動中（flgSTATE=3）
上述した（式２３）により算出される前方障害物の移動経路を用いて前方障害物が自車線内検知可能領域から検知可能領域外へ移動しているか否かを判断する。
・ｄｘ＞０のとき、すなわち前方障害物が相対的に車両右方向に移動している場合
【数２８】
ｙ１＞ｄｙ／ｄｘ・｛ｘ１−ｘ（０）｝＋ｙ（０）（式２８）
【数２９】
ｘ（Ｔ０）≧ｙ（Ｔ０）・tanθ （式２９）
前方障害物の走行状態が（式２８）および（式２９）を満たす場合、すなわち前方障害物との縦方向相対距離がｙ１より小さく、所定時間Ｔ０後の横方向相対距離ｘ（Ｔ０）がレーザレーダ１０の右側境界より外側の場合、前方障害物は自車線内右側の検知可能領域外に移動中であると判断することができる。
【００５２】
・ｄｘ＜０のとき、すなわち前方障害物が相対的に車両左方向に移動している場合
【数３０】
ｙ２＞ｄｙ／ｄｘ・｛ｘ２−ｘ（０）｝＋ｙ（０）（式３０）
【数３１】
ｘ（Ｔ０）≦−ｙ（Ｔ０）・tanθ （式３１）
前方障害物の走行状態が（式３０）および（式３１）を満たす場合、すなわち前方障害物との縦方向相対距離がｙ２より小さく、所定時間Ｔ０後の横方向相対距離ｘ（Ｔ０）がレーザレーダ１０の左側境界より外側の場合、前方障害物は自車線内左側の検知可能領域外に移動中であると判断することができる。
【００５３】
《曲線路の場合》
つぎに、図１０を用いて左カーブの曲線路の場合に障害物がどの方向へ移動しているかを判定する方法を説明する。
所定時間Ｔ０後の前方障害物の位置（ｘ（Ｔ０）、ｙ（Ｔ０））は、上述した（式１９）（式２０）のように表される。また、前方障害物の移動経路は、上述した（式２３）により算出される。
（ｄ）遠方へ移動中（flgSTATE=1）
【数３２】
ｄｙ＞０ （式３２）
【数３３】
ｙ（Ｔ０）≧ｙmax （式３３）
前方障害物の走行状態が（式３２）および（式３３）を満たす場合、すなわち前方障害物の車速が自車速よりも大きく、所定時間Ｔ０後の縦方向相対距離ｙ（Ｔ０）がレーザレーダ１０の最大検知距離ｙmaxよりも大きい場合、前方障害物は遠方に移動中であると判断することができる。
【００５４】
（ｅ）隣接車線へ移動中（flgSTATE=2）
・ｄｘ＞０のとき、すなわち前方障害物が相対的に車両右方向に移動している場合
【数３４】
ｙ１＜ｄｙ／ｄｘ・｛ｘ１−ｘ（０）｝＋ｙ（０）（式３４）
【数３５】
ｙ（Ｔ０）≧√｛（Ｒ＋Ｄ）²−（ｘ（Ｔ０）＋Ｒ）²｝（式３５）
前方障害物の走行状態が（式３４）および（式３５）を満たす場合、すなわち前方障害物との縦方向相対距離がｙ１より大きく、所定時間Ｔ０後の縦方向相対距離ｙ（ｔ０）がカーブ路の自車線右端より外側の場合、前方障害物は右側車線に移動中であると判断することができる。
【００５５】
・ｄｘ＜０のとき、すなわち前方障害物が相対的に車両左方向に移動している場合
【数３６】
ｙ２＜ｄｙ／ｄｘ・｛ｘ２−ｘ（０）｝＋ｙ（０） （式３６）
【数３７】
ｙ（Ｔ０）≧√｛（Ｒ＋Ｄ）²−（ｘ（Ｔ０）＋Ｒ）²｝ （式３７）
前方障害物の走行状態が（式３６）および（式３７）を満たす場合、すなわち前方障害物との縦方向相対距離がｙ２より大きく、所定時間Ｔ０後の縦方向相対距離ｙ（Ｔ０）がカーブ路の自車線右端より外側の場合、前方障害物は右側車線に移動中であると判断することができる。
【００５６】
（ｆ）自車線内右側検知可能領域外に移動中（flgSTATE=3）
・ｄｘ＞０のとき、すなわち前方障害物が相対的に車両右方向に移動している場合
【数３８】
ｙ１＞ｄｙ／ｄｘ・｛ｘ１−ｘ（０）｝＋ｙ（０）（式３８）
【数３９】
ｘ（Ｔ０）≧ｙ（Ｔ０）・tanθ （式３９）
前方障害物の走行状態が（式３８）および（式３９）を満たす場合、すなわち前方障害物との縦方向相対距離がｙ１より小さく、所定時間Ｔ０後の横方向相対距離ｘ（Ｔ０）がレーザレーダ１０の右側境界より外側の場合、前方障害物は自車線内右側の検知可能領域外に移動中であると判断することができる。
【００５７】
（ｇ）自車線内左側検知可能領域外に移動中（flgSTATE=3）
【数４０】
ｘ（Ｔ０）≦−ｙ（Ｔ０）・tanθ （式４０）
【数４１】
ｙ（Ｔ０）≦√｛（Ｒ＋Ｄ）²−（ｘ（Ｔ０）＋Ｒ）²｝（式４１）
前方障害物の走行状態が（式４０）および（式４１）を満たす場合、すなわち所定時間Ｔ０後の横方向相対距離ｘ（Ｔ０）がレーザレーダ１０の左側境界より外側で、所定時間Ｔ０後の縦方向相対距離ｙ（Ｔ０）がカーブ路の自車線右端より内側の場合、前方障害物は自車線内左側の検知可能領域外に移動中であると判断することができる。
ステップＳ６００において障害物状態を推定し、障害物状態フラグflgSTATEを設定した後、ステップＳ７００へ進む。
【００５８】
ステップＳ７００では、ステップＳ６００で推定した障害物の動きに基づいて、ステップＳ４００で算出した反力制御指令値ＦＡを補正する。すなわち、障害物が検知可能領域外へ移行して対象外となったときの状態に応じて反力指令値変化率ΔＦＡを設定し、反力指令補正値ＦＡoutを算出する。反力指令補正値ＦＡoutの補正について、図１１のフローチャートを用いて詳細に説明する。
【００５９】
ステップＳ７０１では、レーザレーダ１０により検出された前方障害物の位置（ｘ（０）、ｙ（０））と、（式９）および（式１０）により設定される自車線内の検知可能領域とから、障害物が自車線内に存在するか否かを判定する。ステップＳ７０１が肯定判定されると、ステップＳ７０２へ進む。ステップＳ７０２で、ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔを０にクリアし、上述したステップＳ４００で算出した反力制御指令値ＦＡを反力指令補正値ＦＡoutとして設定して終了する。ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔは、前方障害物が検出されなった時点からの経過時間（ロスト経過時間）を示す。ステップＳ７０１が否定判定されると、対象外となった時点での障害物の状態に応じた反力指令補正値ＦＡoutを算出するために、ステップＳ７０３に進む。
【００６０】
ステップＳ７０３では、図８のフローチャートに従って設定した障害物状態フラグflgSTATEが１か否かを判断する。ステップＳ７０３が肯定判定されると、前方障害物が遠方に移動して対象外になったと判断し、ステップＳ７０４へ進む。ステップＳ７０４では、反力制御指令値変化率ΔＦＡにΔＦＡ１（例えば１０[kgf/s]）をセットする。ステップＳ７０３が否定判定されると、ステップＳ７０５に進む。
【００６１】
ステップＳ７０５では、障害物状態フラグflgSTATEが２か否かを判定する。ステップＳ７０５が肯定判定されると、前方障害物が隣接車線に移動して対象外になったと判断し、ステップＳ７０６へ進む。ステップＳ７０６では、反力制御指令値変化率ΔＦＡにΔＦＡ２（例えば１０[kgf/s]）をセットする。ステップＳ７０５が否定判定されると、ステップＳ７０７に進む。
【００６２】
ステップＳ７０７では、障害物状態フラグflgSTATEが３か否かを判定する。ステップＳ７０７が肯定判定されると、前方障害物が自車線内検知可能領域外に移動したと判断し、ステップＳ７０８に進む。ステップＳ７０８では、ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔが所定時間Ｔ３（例えば１[sec]）よりも小さいか否かを判定する。所定時間Ｔ３は、前方障害物が自車線内検知可能領域外へ移動した後、隣接車線に移動するまでの所要時間として、予め適切な値を設定しておく。なお、所定時間Ｔ３は、障害物が非検出となったときの位置および相対速度から、自車線外に離脱するまでの時間を算出し、これを所定時間Ｔ３として設定することもできる。
【００６３】
ステップＳ７０８が肯定判定され、ロスト経過時間が所定時間Ｔ３よりも短い場合は、ステップＳ７０９へ進む。ステップＳ７０９では、反力減少の開始タイミングを所定時間Ｔ３だけ遅延させるように、反力制御指令値変化率ΔＦＡに０をセットする。一方、ロスト経過時間が所定時間Ｔ３以上となった場合は、ステップＳ７１０へ進む。ステップＳ７１０では、反力制御指令値変化率ΔＦＡにΔＦＡ３（例えば５[kgf/s]）をセットする。このように、前方障害物が自車線内検知可能領域外に移動した場合は、ロスト経過時間を計測して前方障害物が完全に隣接車線へ移動したか否かを推定し、障害物が自車線からいなくなったと判断してから反力制御指令値の補正を行う。
【００６４】
ステップＳ７０７が否定判定されると、自車線内の障害物が道路の勾配等により突然非検知になったと判断し、ステップＳ７１１へ進む。ステップＳ７１１では、ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔが所定時間Ｔ４（例えば２[sec]）よりも小さいか否かを判定する。ステップＳ７１１が肯定判定されると、ステップＳ７１２へ進み、反力減少の開始タイミングを所定時間Ｔ４だけ遅延させるように、反力制御指令値変化率ΔＦＡに０をセットする。ステップＳ７１１が否定判定されると、ステップＳ７１３へ進み、反力制御指令値変化率ΔＦＡにΔＦＡ４（例えば３[kgf/s]）をセットする。このように、自車線内の障害物が突然検出されなくなった場合は、所定時間Ｔ４経過するまで反力制御指令値の補正は行わない。
【００６５】
上述したように反力制御指令値変化率ΔＦＡを設定した後、ステップＳ７１４へ進む。ステップＳ７１４では、前回周期で設定した反力指令補正値ＦＡoutが反力制御指令値変化率ΔＦＡよりも大きいか否かを判断する。ステップＳ７１４が肯定判定されると、ステップＳ７１５に進む。ステップＳ７１５では、ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔを１だけ加算する。さらに、前回周期で設定した反力指令補正値ＦＡoutから反力制御指令値変化率ΔＦＡを減じた値を、新たな反力指令補正値ＦＡoutとして設定する。
【００６６】
一方、ステップＳ７１４が否定判定されると、ステップＳ７１６へ進む。ステップＳ７１６では、前回の反力指令補正値ＦＡoutは既に反力制御指令値変化率ΔＦＡよりも小さくなっているため、反力指令補正値ＦＡoutに０をセットする。
【００６７】
ステップＳ７００で反力指令補正値ＦＡoutを設定した後、ステップＳ８００へ進む。ステップＳ８００では、ステップＳ７００で算出した反力指令補正値ＦＡoutをアクセルペダル反力制御装置６０へ出力し、今回の処理を終了する。
【００６８】
このように、上述した第１の実施の形態においては、以下のような作用効果を奏することができる。
（１）レーザレーダ１０によって検出されていた障害物が検知可能領域外、あるいは自車線外に離脱して対象外となった場合に、アクセルペダル６２に発生させる操作反力の変化パターンを補正する。これにより、例えば前方車両との車間距離に応じてペダル反力ＦＡが増加している状態で前方車両が存在しなくなった場合に、ペダル反力ＦＡの変化を抑制し、運転者の違和感を低減することができる。
（２）障害物が対象外となった場合に、ペダル反力ＦＡを所定時間遅延させてから低下するので、ペダル反力ＦＡの変化を抑制し、運転者の違和感を低減することができる。
（３）障害物が対象外となった場合に、ペダル反力ＦＡを徐々に低下するので、ペダル反力ＦＡの変化を抑制し、運転者の違和感を低減することができる。
（４）障害物認識部５１によって障害物がどのように移動しているかといった走行状況を認識し、障害物状態推定部５５によって障害物が対象外となった場合の障害物状態を推定する。操作反力補正部５６は、障害物状態の推定結果に基づいて、ペダル反力ＦＡの変化パターンを補正するので、運転者の感覚に合ったペダル反力制御を行うことができる。
（５）障害物状態推定部５５は、検知可能領域算出部５４で算出した、レーザレーダ１０によって検知可能な自車線内の検知可能領域と、障害物認識部５１からの信号とに基づいて、障害物が対象外となった場合の障害物状態を推定する。これにより、障害物の状態をより正確に推定して、運転者の感覚に合ったペダル反力制御を行うことができる。
（６）障害物状態推定部５５は、障害物が対象外となった場合の障害物状態を、（ａ）検知可能領域内で非検知になった（flgSTATE=4）、（ｂ）検知可能領域の右方車線、あるいは左方車線に離脱した（flgSTATE=2）、（ｃ）検知可能領域の遠方に離脱した（flgSTATE=1）、（ｄ）自車線内の検知可能領域外に離脱した（flgSTATE=3）、のいずれかと推定する。障害物が、（ａ）検知可能領域内で非検知になった場合は、第１の減少パターンで、（ｂ）検知可能領域の右方車線、あるいは左方車線に離脱した場合は、第２の減少パターンで、（ｃ）検知可能領域の遠方に離脱した場合は、第３の減少パターンで、（ｄ）自車線内の検知可能領域外に離脱した場合は、第４の減少パターンでペダル反力を低下させる。これにより、障害物が対象外となったときの障害物状態に応じて、運転者の感覚にあった反力制御を行うことができる。
（７）（ａ）検知可能領域内で非検知になったと判断された場合は、自車線前方に障害物が存在するにもかかわらずレーザレーダ１０の一時的な性能低下や勾配等により障害物が非検知になった可能性があるので所定時間Ｔ４だけ遅延させた後、ペダル反力ＦＡをゆっくした速度（第１の速度）ΔＦＡ４で徐々に低下させる。このように所定の遅延時間Ｔ４を設けることにより、もし自車線内に障害物がいた場合でも、運転者は余裕を持ってシステムの状況を判断し、適切な操作を行うことができる。また、自車線内に障害物がいない場合でも、運転者の違和感を低減することができる。
（８）（ｂ）検知可能領域の右方向あるいは左方向の隣接車線に離脱したと判断された場合は、運転者は障害物に対するリスクポテンシャルＲＰを小さく感じる傾向にあるので、ペダル反力ＦＡを速やかな速度（第２の速度）ΔＦＡ２で徐々に低下させる。これにより、障害物が対象外になった場合でも、運転者の感覚にあった反力制御を行うことができる。
（９）（ｃ）検知可能領域の遠方に離脱したと判断された場合は、運転者は障害物に対するリスクポテンシャルＲＰを小さく感じる傾向にあるので、ペダル反力ＦＡを速やかな速度（第３の速度）ΔＦＡ１で徐々に低下させる。これにより、障害物が対象外になった場合でも、運転者の感覚にあった反力制御を行うことができる。
（１０）（ｄ）自車線内の検知可能領域外に離脱したと判断された場合は、例えば障害物が自車線外に離脱するまでの推定時間として設定された所定時間Ｔ３だけ遅延した後、ペダル反力ＦＡをゆっくりした速度（第４の速度）ΔＦＡ３で徐々に低下させる。障害物が対象外となってから隣接車線に離脱したと推定されるまでの時間を所定時間Ｔ３として設定するので、ペダル反力ＦＡの減少開始が必要以上に遅延されることがなく、運転者の感覚に合った反力制御を行うことができる。また、もし障害物が隣接車線に離脱していない場合でも、運転者は余裕を持ってシステムの状況を判断し、適切な操作を行うことができる。ここで、ΔＦＡ１≧ΔＦＡ２≧ΔＦＡ３≧ΔＦＡ４を満たすように反力制御指令値変化率ΔＦＡを設定するので、障害物が対象外になった場合でも、運転者の感覚にあった反力制御を行うことができる。
【００６９】
なお、上述した第１の実施の形態においては、所定時間Ｔ４を所定値としているが、前方障害物が非検知となったときのペダル反力ＦＡの大きさに応じて、所定時間Ｔ４の大きさを変更することもできる。例えば、非検知となったときのペダル反力ＦＡが小さいほど遅延時間Ｔ４を短くすることにより、ペダル反力の減少開始タイミングが必要以上に遅延されることがなく、運転者の感覚に合った反力制御を行うことができる。
【００７０】
《第２の実施の形態》
つぎに、本発明の第２の実施の形態について説明する。図１２は、第２の実施の形態による車両用運転操作補助装置２の構成を示すシステム図であり、図１３は、車両用運転操作補助装置２を搭載する車両の構成図である。図１２および図１３において、図１および図２に示した第１の実施の形態と同様な機能を有する箇所には同一の符号を付している。ここでは、第１の実施の形態との相違点を主に説明する。
【００７１】
第２の実施の形態においては、前方障害物が対象外となったときの自車両の運転者の意図に応じて、操作反力の減少パターンを変更する。
【００７２】
車線認識カメラ４０は、フロントウィンドウ上部に取り付けられた小型のＣＣＤカメラ、またはＣＭＯＳカメラ等であり、前方道路の状況を画像として検出し、コントローラ５０Ａへと出力する。車線認識カメラ４０は、自車両前方の数ｍ〜数１０ｍ先の路面を撮影し、撮影した画像に基づいて自車両と走行中の車線区分線（白線）との相対的な位置関係を検出する。
【００７３】
具体的には、車線認識カメラ４０は、ＣＣＤ素子で撮像した画像に画像処理を施して道路上の白線を検出し、また、道路形状と車両挙動を表す複数のパラメータ（以後、道路パラメータ）を検出する。さらに、車線認識カメラ４０は、道路パラメータを用いて白線の形状を数学的に表現した白線モデルと、白線の検出結果とが一致するように、道路パラメータを時間と共に更新していくことによって、道路白線を検出して道路形状及び車両挙動を推定する機能をもっている。ここで、道路パラメータは、車線中心線（自車線の中央）に対する自車の重心点横変位ｙｃ、車線中心線に対する自車のヨー角φｒ、車両のピッチ角η、車線認識カメラ４０の路面からの高さｈ、道路曲率（曲率半径の逆数）ρ、車線幅２Ｄ等である。
【００７４】
さらに、車線認識カメラ４０は、検出した白線と路面との境界点数や白線と路面との境界点の連続性などに基づいて、白線が実線であるか破線であるかの判別を行い、この判別結果に基づいて、現在自車両が走行している車線が走行車線であるか追い越し車線であるかを判断する。車線認識カメラ４０は、自車両が走行している車線の種別を判断した走行車線判断信号、および推定した道路パラメータをコントローラ５０Ａへ出力する。
【００７５】
図１４はコントローラ５０Ａの内部構成を示すブロック図である。コントローラ５０Ａは、ＣＰＵのソフトウェア形態により、障害物認識部５１Ａ、リスクポテンシャル算出部５２Ａ、運転操作反力決定部５３Ａ、検知可能領域算出部５４Ａ、障害物状態推定部５５Ａ、運転操作反力補正部５６Ａ、走行位置認識部５７Ａおよびドライバー意図推定部５８Ａを構成する。なお、障害物認識部５１Ａ、リスクポテンシャル算出部５２Ａ、運転操作反力決定部５３Ａ、検知可能領域算出部５４Ａおよび障害物状態推定部５５Ａにおける処理は、上述した第１の実施の形態と同様である。
【００７６】
走行位置認識部５７Ａは、車線認識カメラ４０から入力される道路パラメータおよび走行車線判断信号に基づいて、自車両が所定時間後に到達すると予測される走行中の車線中央からの横変位を算出し、自車両が車線内をどのように移動しているかを推定する。
【００７７】
ドライバー意図推定部５８Ａは、障害物状態推定部５５Ａによって推定された障害物の移動状態と、走行位置認識部５７Ａによって算出された自車両の移動状態と、車線認識カメラ４０から入力される走行車線判断信号とに基づいて、運転者の意図を推定する。具体的には、レーザーレーダー１０が前方障害物を検出しなくなった（ロストした）、または前方障害物がレーザレーダ１０の検知領域外へ移動した原因が、自車両の運転者の意図によるものか、前方障害物である先行車両の挙動によるものなのかを推定し、これにより運転者の意図を推定する。
【００７８】
運転操作反力補正部５６Ａは、障害物状態推定部５５Ａで推定された障害物の動きと、ドライバー意図推定部５８Ａで推定された運転者の意図とに基づいて、障害物が対象外となったときの状態に応じて、運転操作反力決定部５３Ａで算出した反力制御量を補正する。
【００７９】
次に第２の実施の形態による車両用運転操作補助装置２の動作を図１５を用いて説明する。図１５は、第２の実施の形態によるコントローラ５０Ａにおける運転操作補助制御処理の処理手順を示すフローチャートである。なお、本処理内容は、一定間隔、例えば５０ｍｓｅｃ毎に連続的に行われる。
【００８０】
まず、ステップＳ１１００で走行状態を読み込む。ここで、走行状態は、自車前方の障害物状況を含む自車両の走行状況に関する情報である。そこで、レーザレーダ１０、車速センサ２０および操舵角センサ３０による検出信号を読み込む。また、車線認識カメラ４０によって検出される、車線中心線に対する自車両の横変位ｙｃ、車線中心線に対するヨー角φｒ、道路曲率（曲率半径Ｒの逆数）ρ、及び走行車線判断信号を読み込む。
【００８１】
ステップＳ１２００では、第１の実施の形態における図４のステップＳ２００と同様に、ステップＳ１１００で読み込み、認識した走行状態データに基づいて、前方障害物の状況を認識する。ここでは、現在の障害物の自車両に対する相対位置やその移動方向・移動速度を認識し、自車両の走行に対して障害物が、自車両の前方にどのように配置され、相対的にどのように移動しているかを認識する。
【００８２】
ステップＳ１２５０では、ステップＳ１１００で読み込んだ道路パラメータおよび走行車線判断信号から、所定時間後の自車両の走行位置を算出する。具体的には、自車両の横変位ｙｃ、ヨー角φｒ、道路曲率ρ等に基づいて自車両が所定時間後に到達すると予測される、車線中央からの横変位ｙｓを算出する。なお、所定時間後の横変位ｙｓは、現在自車両が走行している車線の中央からの横変位、あるいは自車両が車線変更を行っている場合は、車線変更前の車線の車線中央からの横変位である。所定時間Ｔ後の車両の横変位ｙｓは、車体の向きが車両の進行方向を向いていると仮定した場合、自車速Ｖ、自車両のヨー角φｒおよび自車両の現在の横変位ｙｃを用いて、以下の（式４２）で求められる。
【数４２】
ｙｓ＝ｙｃ＋Ｖ・Ｔ・φｒ （式４２）
【００８３】
（式４２）に示すように、所定時間後の横変位ｙｓは、自車両が速度Ｖで所定時間Ｔだけ走行した距離Ｌ＝Ｖ・Ｔにおける、車線中央からの横変位である。そこで、この横変位ｙｓを前方注視点横変位とする。また、距離Ｌを前方注視点距離とする。
【００８４】
なお、前方注視点横変位ｙｓは、現在の横変位ｙｃの微分値ｄｙｃ／ｄｔを用いて、以下の（式４３）により算出することもできる。
【数４３】
ｙｓ＝ｙｃ＋Ｔｄｙｃ／ｄｔ （式４３）
【００８５】
また、自車両が曲線路を走行している場合は、横変位の予測値のずれを補正するように、（式４４）を用いて前方注視点横変位ｙｓを算出することもできる。
【数４４】
ｙｓ＝ｙｃ＋Ｖ・Ｔ・φｒ−（Ｖ・Ｔ）²／２・ρ （式４４）
【００８６】
ステップＳ１３００では、障害物に対するリスクポテンシャルＲＰを算出し、つづくステップＳ１４００では、算出したリスクポテンシャルＲＰに応じた反力制御指令値ＦＡを算出する。これらの処理は、上述した図４のフローチャートのステップＳ３００およびステップＳ４００での処理と同様であるので省略する。
【００８７】
ステップＳ１５００では、レーザレーダ１０によりスキャンされる前方の領域（例えば自車正面に対して±６[deg]）から、自車線内の検知可能領域を算出する。図１６に、自車両が直線路を走行している場合の検知可能領域を示し、図１７に、自車両が曲線路を走行している場合の検知可能領域を示す。自車線内の検知可能領域は、上述した図４のフローチャートのステップＳ５００での処理と同様にして算出することもできるが、自車両が曲線路を走行している場合は、例えば以下のように算出することもできる。
【００８８】
図１６および図１７に示すように、自車両前面の中心位置を原点として、車両前後方向をｙ軸、車両左右方向をｘ軸とする座標系を設定する。なお、車両前方向を＋ｙ方向、車両右方向を＋ｘ方向とする。レーザレーダのスキャニング幅を２θ、レーザレーダ１０の最長検知距離をｙmax、車線幅を２Ｄとする。
【００８９】
《曲線路の場合》
レーダスキャン範囲の境界は、（式４５）で表される。
【数４５】
ｘ＝±ｙ・tanθ （式４５）
【００９０】
・曲率半径｜Ｒ｜の右カーブの場合（図１７参照）
簡単な幾何学的な関係から、走行車線の左右の境界は、（式１１）により算出される曲率半径Ｒを用いて、以下の（式４６）（式４７）で表される。
【数４６】
走行車線左境界ｘ＝｜Ｒ｜−√｛（｜Ｒ｜＋Ｄ）²−ｙ²｝ （式４６）
【数４７】
走行車線右境界ｘ＝｜Ｒ｜−√｛（｜Ｒ｜−Ｄ）²−ｙ²｝ （式４７）
ただし、ｙ≦｜Ｒ｜−Ｄ
【００９１】
図１７に示すように、レーダスキャン範囲と走行車線の左右の境界に挟まれた領域が検知可能領域であり、曲率半径｜Ｒ｜の右カーブの場合、検知可能領域は、以下の（式４８）で示される。
【数４８】
−ｙ・tanθ≦ｘ≦ｙ・tanθ かつ、
｜Ｒ｜−√｛（｜Ｒ｜＋Ｄ）²−ｙ²｝≦ｘ≦｜Ｒ｜−√｛（｜Ｒ｜−Ｄ）²−ｙ²｝ （式４８）
ただし、０＜ｙ≦ｙmax≦｜Ｒ｜−Ｄ
【００９２】
・曲率半径｜Ｒ｜の左カーブの場合
走行車線の左右の境界は、以下の（式４９）（式５０）で表される。
【数４９】
走行車線左境界ｘ＝−｜Ｒ｜＋√｛（｜Ｒ｜−Ｄ）²−ｙ²｝ （式４９）
【数５０】
走行車線右境界ｘ＝−｜Ｒ｜＋√｛（｜Ｒ｜＋Ｄ）²−ｙ²｝ （式５０）
ただし、ｙ≦｜Ｒ｜−Ｄ
【００９３】
これより、曲率半径｜Ｒ｜の左カーブの場合、検知可能領域は以下の（式５１）で示される。
【数５１】
−ｙ・tanθ≦ｘ≦ｙ・tanθ かつ、
−｜Ｒ｜＋√｛（｜Ｒ｜−Ｄ）²−ｙ²｝≦ｘ≦−｜Ｒ｜＋√｛（｜Ｒ｜＋Ｄ）²−ｙ²｝ （式５１）
ただし、０＜ｙ≦ｙmax≦｜Ｒ｜−Ｄ
【００９４】
ここでは、車速と操舵角とから自車両の旋回半径を求めて進行方向を推定しているが、これに限らず、例えば、ヨーレートセンサーや横加速度センサーを用いて自車両の進行方向を検出することもできる。また、前方風景を撮影したカメラ画像を画像処理して白線を認識したり、ナビゲーションシステムから得られた道路情報を元に道路形状を推定してもよい。
ステップＳ１５００でレーザレーダ１０の検知可能領域を算出した後、ステップＳ１６００へ進む。
【００９５】
ステップＳ１６００では、ステップＳ１２００で認識した現在の障害物の自車両に対する相対位置やその移動方向・移動速度と、ステップＳ１５００で算出した自車線内の検知可能領域とから、障害物が自車線内の検知可能領域をどのように移動しているかを推定する。ステップＳ１６００で行う処理を、図１８のフローチャートを用いて説明する。
【００９６】
ステップＳ１６０１では、レーザレーダ１０により前方障害物を検知しているか否かを判定する。ステップＳ１６０１が肯定判定されると、ステップＳ１６０２へ進む。ステップＳ１６０２では、前方障害物が遠方に移動中か否かを判定する。ステップＳ１６０２が肯定判定されると、ステップＳ１６０３へ進み、障害物状態フラグflgSTATEに１０をセットする。ステップＳ１６０２が否定判定されると、ステップＳ１６０４へ進む。
【００９７】
ステップＳ１６０４では、前方障害物が右側の隣接車線に移動中か否かを判定する。ステップＳ１６０４が肯定判定されると、ステップＳ１６０５に進み、障害物状態フラグflgSTATEに２０をセットする。ステップＳ１６０４が否定判定されると、ステップＳ１６０６へ進む。
【００９８】
ステップＳ１６０６では、前方障害物が左側の隣接車線に移動中か否かを判定する。ステップＳ１６０６が肯定判定されると、ステップＳ１６０７に進み、障害物状態フラグflgSTATEに３０をセットする。ステップＳ１６０６が否定判定されると、ステップＳ１６０８に進む。
【００９９】
ステップＳ１６０８では、前方障害物が自車線内検知可能領域外に移動中か否かを判定する。ステップＳ１６０８が肯定判定されると、ステップＳ１６０９に進み、障害物状態フラグflgSTATEに４０をセットする。ステップＳ１６０８が否定判定されると、ステップＳ１６１０に進み、障害物状態フラグflgSTATEに５０をセットする。
【０１００】
ステップＳ１６０１で前方障害物を検知していないと判定されると、ステップＳ１６１１に進む。ステップＳ１６１１では、前回周期で算出したアクセルペダル反力制御指令補正値ＦＡoutが０か否かを判定する。ステップＳ１６１１が肯定判定されると、ステップＳ１６１２に進み、障害物状態フラグflgSTATEを０にクリアする。一方、ステップＳ１６１１が否定判定され、反力指令補正値ＦＡoutが０でない場合は、前回周期でセットした障害物状態フラグflgSTATEをそのまま使用する。
【０１０１】
上述したステップＳ１６０２、ステップＳ１６０４、ステップＳ１６０６およびステップＳ１６０８における、前方障害物がそれぞれ遠方、隣接車線、自車線内検知可能領域外に移動中であるか否かの判定は、所定時間Ｔ０（例えばＴ０＝１[sec]）後の障害物の位置に基づいて行うことができる。この判定は、上述した第１の実施の形態と同様にして行うこともできるが、以下のようにして判定することもできる。これらの判定方法を、道路形状別に図１６および図１７を用いて説明する。ここで、前方障害物の位置を（ｘ（０）、ｙ（０））、相対速度を（ｄｘ、ｄｙ）とする。
【０１０２】
《直線路の場合》
まず、図１６を用いて直線路の場合に障害物がどの方向へ移動しているかを判定する方法を説明する。
所定時間Ｔ０後の、前方障害物の位置（ｘ（Ｔ０）、ｙ（Ｔ０））は、（式５２）のように表される。
【数５２】

である。
【０１０３】
（ｈ）遠方に移動中（flgSTATE=10）
−ｙ・tanθ≦ｘ（０）≦ｙ・tanθ、かつ、−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθを満たす十分大きいＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式５３）を満たす場合、前方障害物が遠方に移動中であると判断することができる。
【数５３】
ｙ（Ｔ０）≧ｙmax （式５３）
【０１０４】
（ｉ）右側の隣接車線へ移動中（flgSTATE=20）
−Ｄ≦ｘ（０）≦Ｄ≦ｘ（Ｔ０）、かつ、０＜ｙ（０）、ｙ（Ｔ０）≦ｙmaxを満たす十分小さなＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式５４）を満たす場合、前方障害物が右方向へ移動中であると判断することができる。
【数５４】
−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθ （式５４）
【０１０５】
（ｊ）左側の隣接車線へ移動中（flgSTATE=30）
ｘ（Ｔ０）≦−Ｄ≦ｘ（０）≦Ｄ、かつ、０＜ｙ（０）、ｙ（Ｔ０）≦ｙmaxを満たす十分小さなＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式５５）を満たす場合、前方障害物が左方向へ移動中であると判断することができる。
【数５５】
−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθ （式５５）
【０１０６】
（ｋ）自車線内検知可能領域外に移動中（flgSTATE=40）
−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθでない十分小さなＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式５６）を満たす場合、前方障害物が自車線内検知可能領域外へ移動中であると判断することができる。
【数５６】
−Ｄ≦ｘ（Ｔ０）≦Ｄ （式５６）
【０１０７】
《曲線路の場合》
つぎに、図１７を用いて曲線路の場合に障害物がどの方向へ移動しているかを判定する方法を説明する。ここでは、右カーブを例として説明する。
（ｌ）遠方へ移動中（flgSTATE=10）
−ｙ・tanθ≦ｘ（０）≦ｙ・tanθ、かつ、−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθを満たす十分大きいＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式５７）を満たす場合、前方障害物が遠方へ移動中であると判断することができる。
【数５７】
ｙ（Ｔ０）≧ｙmax （式５７）
【０１０８】
（ｍ）隣接車線に移動中
・右側の隣接車線に移動中（flgSTATE=20）
｜Ｒ｜−√｛（｜Ｒ｜＋Ｄ）²−ｙ²｝≦ｘ（０）≦｜Ｒ｜−√｛（｜Ｒ｜−Ｄ）²−ｙ²｝≦ｘ（Ｔ０）、かつ、０＜ｙ（０）、ｙ（Ｔ０）≦ｙmax を満たす十分小さなＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式５８）を満たす場合、前方障害物は右方向へ移動中であると判断することができる。
【数５８】
−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθ （式５８）
【０１０９】
・左側の隣接車線に移動中（flgSTATE=30）
ｘ（Ｔ０）≦｜Ｒ｜−√｛（｜Ｒ｜＋Ｄ）²−ｙ²｝≦ｘ（０）≦｜Ｒ｜−√｛（｜Ｒ｜−Ｄ）²−ｙ²｝、かつ、０＜ｙ（０）、ｙ（Ｔ０）≦ｙmaxを満たす十分小さなＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式５９）を満たす場合、前方障害物は左車線へ移動中であると判断することができる。
【数５９】
−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθ （式５９）
【０１１０】
（ｎ）自車線内検知可能領域外に移動中（flgSTATE=40）
−ｙ・tanθ≦ｘ（Ｔ０）≦ｙ・tanθでない十分小さなＴ０を繰り返し計算で求め、前方障害物の走行状態が以下の（式６０）を満たす場合、前方障害物は自車線内検知可能領域外に移動中であると判断することができる。
【数６０】
｜Ｒ｜−√｛（｜Ｒ｜＋Ｄ）²−ｙ²｝≦ｘ（Ｔ０）≦｜Ｒ｜−√｛（｜Ｒ｜−Ｄ）²−ｙ²｝ （式６０）
なお、左カーブの場合でも同様にして障害物状態を算出することができる。
このようにステップＳ１６００で障害物状態を推定した後、ステップＳ１６５０へ進む。
【０１１１】
ステップＳ１６５０では、ステップＳ１１００で読み込んだ道路パラメータおよびステップＳ１６００で推定した障害物状態に基づいて、ドライバー意図判別処理を行う。運転者の意図をどのように推定するかについて、図１９のフローチャートを用いて詳細に説明する。
【０１１２】
ステップＳ１６５１では、車線認識カメラ４０から入力された走行車線判断信号に基づき、追い越し車線と走行車線のうち、現在、自車両が走行車線を走行しているか否かを判定する。ステップＳ１６５１が肯定判定されると、ステップＳ１６５２へ進む。
【０１１３】
ステップＳ１６５２では、自車両が走行車線から追い越し車線へ車線変更中であるか否か判定する。ここで行う車線変更中か否かの判定方法については、後述する。ステップＳ１６５２が否定判定され、自車両が車線変更することなく走行車線を走行している場合は、ステップＳ１６６０へ進む。ステップＳ１６６０では、ドライバー意図判別処理Ａ１（図２１を用いて後述）を行い、自車両の運転者の運転操作意図を推定する。ステップＳ１６５２が肯定判定され、自車両が走行車線から追い越し車線へ移動している場合は、ステップＳ１６７０へ進み、ドライバー意図判別処理Ａ２（図２２を用いて後述）を行う。
【０１１４】
一方、ステップＳ１６５１が否定判定され、自車両が走行車線を走行中でなＩ場合は、ステップＳ１６５５へ進む。ステップＳ１６５５では、自車両が追い越し車線から走行車線へ車線変更中であるか否か判定する。ステップＳ１６５５が否定判定され、自車両が車線変更することなく追い越し車線を走行している場合は、ステップＳ１６８０へ進む。ステップＳ１６８０では、ドライバー意図判別処理Ｂ１（図２３を用いて後述）を行う。ステップＳ１６５５が肯定判定され、自車両が追い越し車線から走行車線へ移動している場合は、ステップＳ１６９０へ進み、ドライバー意図判別処理Ｂ２（図２４を用いて後述）を行う。
【０１１５】
ここで、ステップＳ１６５２およびステップＳ１６５５における、自車両の車線変更判定処理の詳細について、図２０（ａ）〜（ｄ）を用いて説明する。図２０（ａ）〜（ｄ）は、自車両が走行車線から追い越し車線へと車線変更を行っていく様子を時間経過順に示している。
【０１１６】
図２０（ａ）（ｂ）は自車両が走行車線内を走行している様子を示している。図２０（ａ）において、自車両は走行車線内を直進している。このときの自車両の横変位ｙｃは、車線幅２Ｄおよび自車両の幅２Ｗを用いて、ｙｃ＜Ｄ−Ｗである。また、上述した（式４２）を用いて算出される所定時間Ｔ後の横変位、すなわち前方注視点横変位ｙｓは、ｙｓ＜Ｄ−Ｗである。図２０（ｂ）では、自車両は直進はしていないが、自車線に対するヨー角φｒはまだ十分に小さく、車線変更には至っていない。このときの自車両の横変位ｙｃは、ｙｃ＜Ｄ−Ｗである。また、前方注視点横変位ｙｓは、ｙｓ＜Ｄである。
【０１１７】
したがって、自車両の現在の横変位ｙｃおよび前方注視点横変位ｙｓが以下の（式６１）を満たす場合、自車両は車線変更を行っておらず、走行車線を走行していると判断する。
【数６１】
ｙｓ＜Ｄ、かつ、ｙｃ＜Ｄ−Ｗ （式６１）
【０１１８】
このように、自車両が車線区分線（白線）をまたがない状態、かつ、前方注視点横変位ｙｓが走行車線内に存在している場合に、自車両がまだ車線変更の動作に移っていないと判断することができる。したがって、自車両の走行状態が（式６１）を満たす場合に、ステップＳ１６５２が否定判定される。
【０１１９】
図２０（ｃ）は、自車両が走行車線から追い越し車線へ車線変更を行っている最中で、自車両が白線をまたいでいる様子を示している。自車両の現在の横変位ｙｃおよび前方注視点横変位ｙｓが以下の（式６２）を満たす場合、自車両が走行車線から追い越し車線へ車線変更中であると判断する。
【数６２】
Ｄ−Ｗ≦ｙｃ≦Ｄ＋Ｗ、かつ、ｙｓ≧Ｄ （式６２）
【０１２０】
図２０（ｄ）は、自車両が追い越し車線への車線変更を完了した状態を示している。自車両の現在の横変位ｙｃおよび前方注視点横変位ｙｓが以下の（式６３）を満たす場合、走行車線から追い越し車線への車線変更が完了したと判断する。
【数６３】
ｙｃ＞Ｄ＋Ｗ、かつ、ｙｓ＞Ｄ＋Ｗ （式６３）
【０１２１】
したがって、自車両の現在の横変位ｙｃおよび前方注視点横変位ｙｓが以下の（式６４）を満たす場合、自車両が走行車線から追い越し車線へ車線変更中であると判断し、ステップＳ１６５２が肯定判定される。
【数６４】
ｙｃ≧Ｄ−Ｗ、かつ、ｙｓ≧Ｄ （式６４）
なお、追い越し車線から走行車線への車線変更も同様にして判断することができる。
【０１２２】
つぎに、ステップＳ１６６０、Ｓ１６７０，Ｓ１６８０およびＳ１６９０におけるドライバー意図判別処理を説明する。ここでは、ステップＳ１６００で判定した前方障害物の状態と、ステップＳ１６５２，Ｓ１６５５で判定した自車両の走行状態とに応じて運転者の意図を判別する。まず、ステップＳ１６６０でのドライバー意図判別処理Ａ１について、図２１を用いて説明する。なお、処理Ａ１は、自車両が走行車線での走行を維持している場合の処理である。
【０１２３】
ステップＳ１６６１で、ステップＳ１６００で設定した障害物状態フラグflgSTATE＝１０であるか否かを判定する。ステップＳ１６６１が肯定判定された場合は、例えば図２５に示すように、自車両が走行車線での走行を維持しているときに先行車がさらに前方へと遠ざかっていく状態である。そこで、ステップＳ１６６２へ進み、運転者の意図を示す意図判断フラグflgAIMを０（巡航）にセットする。ステップＳ１６６１が否定判定されると、ステップＳ１６６３へ進む。
【０１２４】
ステップＳ１６６３では、障害物状態フラグflgSTATE＝２０であるか否かを判定する。ステップＳ１６６３が肯定判定された場合は、例えば図２６に示すように、自車両が走行車線での走行を維持しているときに先行車が追い越し車線へと車線変更を行った状態である。そこで、ステップＳ１６６４へ進み、意図判断フラグflgAIMを０（巡航）にセットする。ステップＳ１６６３が否定判定されると、ステップＳ１６６５へ進む。
【０１２５】
ステップＳ１６６５では、障害物状態フラグflgSTATE＝３０であるか否かを判定する。ステップＳ１６６５が肯定判定された場合は、例えば図２７に示すように、自車両が走行車線での走行を維持しているときに先行車が左分岐に進入していく状態である。そこで、ステップＳ１６６６へ進み、意図判断フラグflgAIMを０（巡航）にセットする。ステップＳ１６６５が否定判定されると、ステップＳ１６６７へ進む。
【０１２６】
ステップＳ１６６７以降の処理では、障害物判定フラグflgSTATEの値にかかわらず意図判断フラグflgAIMを０（巡航）にセットする。
【０１２７】
このように、自車両が車線変更を行わずに走行車線を走行している場合は、運転者は走行車線での走行を維持し、定常的に走行しようとしていると推定し、前方障害物の状態にかかわらず意図判断フラグflgAIMを０にセットする。
【０１２８】
つぎに、ステップＳ１６７０でのドライバー意図判別処理Ａ２について、図２２を用いて説明する。なお、処理Ａ２は、自車両が走行車線から追い越し車線へ車線変更している場合の処理である。
ステップＳ１６７１で、障害物判断フラグflgSTATE＝１０であるか否か、すなわち、前方障害物が遠方に移動中か否かを判定する。ステップＳ１６７１が肯定判定された場合、運転者の追い越し車線への車線変更と同時に前方障害物が遠ざかっていく状態なので、運転者の意図としては先行車両に着いて行こうとしているものと推定する。そこで、ステップＳ１６７２へ進み、意図判断フラグflagAIMに2０（追走）をセットする。ステップＳ１６７１が否定判定されると、ステップＳ１６７３へ進む。
【０１２９】
ステップＳ１６７３で、障害物判断フラグflgSTATE＝２０であるか否か、すなわち、前方障害物が右側車線に移動中か否かを判定する。ステップＳ１６７３が肯定判定された場合、自車両が追い越し車線へ移動中に、前方の障害物がさらに右方向へ移動して非検出となっている。これは、先行車が右分岐を行った場合、あるいはレーザーレーダー１０の誤検知等の可能性がある。そこで、運転者の意図としては、現状維持と推定し、ステップＳ１６７４へ進んで意図判断フラグflagAIMに0（巡航）をセットする。ステップＳ１６７３が否定判定されると、ステップＳ１６７５に移行する。
【０１３０】
ステップＳ１６７５では、障害物判断フラグflgSTATE＝３０であるか否か、すなわち、前方障害物が左側車線に移動中か否かを判定する。ステップＳ１６７５が肯定判定された場合、例えば図２８に示すように、先行車両は走行車線を維持している状態で、自車両だけが追い越し車線へ移動している状態と考えられる。そこで、運転者には追い越しの意図があると推定し、ステップＳ１６７６へ移行して意図判断フラグflagAIMに1（追い越し）をセットする。ステップＳ１６７５が否定判定されると、ステップＳ１６７７へ進む。
【０１３１】
ステップＳ１６７７以降の処理では、障害物判定フラグflgSTATEの値にかかわらず意図判断フラグflgAIMを０（巡航）にセットする。
【０１３２】
つぎに、ステップＳ１６８０でのドライバー意図判別処理Ｂ１について、図２３を用いて説明する。なお、処理Ｂ１は、自車両が追い越し車線での走行を維持している場合の処理である。
【０１３３】
ステップＳ１６８１では、障害物判断フラグflgSTATE＝１０であるか否か、すなわち、前方障害物が遠方に移動中か否かを判定する。ステップＳ１６８１が肯定判定された場合、例えば図２９に示すように、自車両の前方を走行中の車両がさらに前方へと遠ざかっていくような状況であるが、運転者は追い越し車線を維持しようとしている状態である。そこで、運転者の意図としては先行車両に着いて行こうとしていると推定し、ステップＳ１６８２へ移行して意図判断フラグflagAIMに2（追走）をセットする。ステップＳ１６８１が否定判定されると、ステップＳ１６８３に移行する。
【０１３４】
ステップＳ１６８３では、障害物判断フラグflgSTATE＝２０であるか否か、すなわち、前方障害物が右方向に移動中か否かを判定する。ステップＳ１６８３が肯定判定された場合、自車両が追い越し車線を走行中に、前方の障害物がさらに右方向へ移動して非検出となるという状況である。これは、先行車が右分岐に進入している、あるいはレーザーレーダ１０の誤検知等の可能性がある。そこで、運転者の意図としては、現状維持と推定し、ステップＳ１６８４へ移行して意図判断フラグflagAIMに0（巡航）をセットする。ステップＳ１６８３が否定判定されると、ステップＳ１６８５へ進む。
【０１３５】
ステップＳ１６８５では、障害物判断フラグflgSTATE＝３０であるか否か、すなわち、前方障害物が左方向に移動中か否かを判定する。ステップＳ１６８５が肯定判定された場合、例えば図３０に示すように、先行車両が追い越し車線から走行車線へ移動している状態である。自車両はそのまま追い越し車線での走行を維持した状態であるから、運転者には追い越しの意図があると推定し、ステップＳ１６８６へ移行して意図判断フラグflagAIMに1（追い越し）をセットする。ステップＳ１６８５が否定判定されると、ステップＳ１６８７へ進む。
【０１３６】
ステップＳ１６８７以降の処理では、障害物判定フラグflgSTATEの値にかかわらず意図判断フラグflgAIMを０（巡航）にセットする。
【０１３７】
つぎに、ステップＳ１６９０でのドライバー意図判別処理Ｂ２について、図２４を用いて説明する。なお、処理Ｂ２は、自車両が追い越し車線から走行車線への車線変更を行っている場合の処理である。
【０１３８】
ステップＳ１６９１では、障害物判断フラグflgSTATE＝１０であるか否か、すなわち、前方障害物が遠方に移動中か否かを判定する。ステップＳ１６９１が肯定判定された場合、自車両の前方を走行中の車両がさらに前方へと遠ざかっていくような状況であるが運転者は追い越しを止めて、走行車線へ戻ろうとしている状態である。そこで、運転者の意図としては現状維持と判断し、ステップＳ１６９２へ移行して意図判断フラグflagAIMに０（巡航）をセットする。ステップＳ１６９１が否定判定されると、ステップＳ１６９３に移行する。
【０１３９】
ステップＳ１６９３では、障害物判断フラグflgSTATE＝２０であるか否か、すなわち、前方障害物が右方向に移動中か否かを判定する。ステップＳ１６９３が肯定判定された場合、例えば図３１に示すように、自車両が、追い越し車線を走行中の車両を走行車線から追い越すような状況になりつつあると推定する。そこで、現在の走行状況を運転者に知らせ、積極的な加速を抑制するために、ステップＳ１６９４へ移行して意図判断フラグflagAIMに３（非加速）をセットする。ステップＳ１６９３が否定判定されると、ステップＳ１６９５へ進む。
【０１４０】
ステップＳ１６９５以降の処理では、障害物判定フラグflgSTATEの値にかかわらず意図判断フラグflgAIMを０（巡航）にセットする。
上述したようにステップＳ１６５０でのドライバー意図判別処理を行った後、ステップＳ１７００へと進む。
【０１４１】
ステップＳ１７００では、ステップＳ１６００で推定した障害物の動きと、ステップＳ１６５０で推定したドライバー意図とに基づいて、障害物が対象外となったときの状態に応じて、ステップＳ１４００で算出した反力制御指令値ＦＡを補正し、反力指令補正値ＦＡoutを算出する。ステップＳ１７００における反力指令補正値ＦＡout算出の処理を、図３２のフローチャートを用いて説明する。
【０１４２】
ステップＳ１７０１では、レーザレーダ１０により検出された前方障害物の位置（ｘ（０）、ｙ（０））と自車線内の検知可能領域とから、障害物が自車線内の検知可能領域に存在するか否かを判定する。ステップＳ１７０１が肯定判定されると、ステップＳ１７０２へ進む。ステップＳ１７０２では、前方障害物が検出されなくなった（ロストした）時点からの経過時間を示すロスト経過時間カウンタＣｎｔ＿ｌｏｓｔを０にクリアする。また、ステップＳ１４００で算出した反力制御指令値ＦＡを反力指令補正値ＦＡoutに設定する。
【０１４３】
ステップＳ１７０１が否定判定されると、ステップＳ１７０３に進み、障害物状態フラグflgSTATEが１０または２０または３０のいずれかであるか否かを判定する。ステップＳ１７０３が肯定判定され、前方障害物が遠方、右車線あるいは左車線に移動したために対象外となった場合は、ステップＳ１７２０へ進む。ステップＳ１７２０では、図３３のフローチャートに示すように、運転操作反力補正処理Ａを行う。
【０１４４】
ステップＳ１７２０での運転操作反力補正処理Ａにおいて、まず、ステップＳ１７２１では、意図判断フラグflgAIMが１か否かを判定する。ステップＳ１７２１が肯定判定され、運転者の意図が追い越しである場合には、ステップＳ１７２２へ進む。ステップＳ１７２２では、反力制御指令値変化率ΔＦＡにΔＦＡ５ (例えば１０[kgf/s])をセットする。ステップＳ１７２１が否定判定されると、ステップＳ１７２３へ移行する。
【０１４５】
ステップＳ１７２３では、意図判断フラグflgAIMが２か否かを判定する。ステップＳ１７２３が肯定判定され、運転者の意図が先行車両に着いて行こうとしている場合は、ステップＳ１７２４へ進む。ステップＳ１７２４では、反力制御指令値変化率ΔＦＡにΔＦＡ６ (例えば８[kgf/s])をセットする。ステップＳ１７２３が否定判定されると、ステップＳ１７２５に移行する。
【０１４６】
ステップＳ１７２５では、意図判断フラグflgAIMが３か否かを判定する。ステップＳ１７２５が肯定判定され、自車両が、追い越し車線を走行中の車両を走行車線から追い越すような状況である場合は、ステップＳ１７２６へ進む。ステップＳ１７２６では、現在の走行状況を運転者に知らせて積極的な加速を抑制するため、反力制御指令値変化率ΔＦＡにΔＦＡ７ (例えば４[kgf/s])をセットする。ステップＳ１７２５が否定判定されると、ステップＳ１７２７に移行し、反力制御指令値変化率ΔＦＡにΔＦＡ８(例えば８[kgf/s])をセットする。
【０１４７】
なお、ステップＳ１７２２，Ｓ１７２４，Ｓ１７２６，Ｓ１７２８で設定した反力制御指令値変化率ΔＦＡ５〜ΔＦＡ８は、ΔＦＡ５≧ΔＦＡ６≧ΔＦＡ８≧ΔＦＡ７の関係を満たすように、予め適切な値を設定しておく。
【０１４８】
一方、図３２のフローチャートにおいてステップＳ１７０３が否定判定され、前方障害物が自車線内検知可能領域外に移動して非検出となった、または前方障害物が道路の勾配等により非検出となった、またはもともと前方障害物が存在しない場合は、ステップＳ１７４０へ進む。ステップＳ１７４０では、図３４のフローチャートに示すように、運転操作反力補正処理Ｂを行う。
【０１４９】
ステップＳ１７４０での運転操作反力補正処理Ｂにおいて、まず、ステップＳ１７４１では、障害物状態フラグflgSTATEが４０か否かを判定する。ステップＳ１７４１が肯定判定され、前方障害物が自車線内検知可能領域外に移動した場合は、ステップＳ１７４２へ移行する。ステップＳ１７４２では、ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔが所定時間Ｔ３（例えば１[sec]）よりも小さいか否かを判定する。ここで、所定時間Ｔ３は、上述した第１の実施の形態の運転操作反力補正処理（図１１のＳ７０８）で用いた値と同じである。
【０１５０】
ステップＳ１７４２が肯定判定されると、ステップＳ１７４３へ進み、反力減少の開始タイミングを所定時間Ｔ３だけ遅延させるように、反力制御指令値変化率ΔＦＡに０をセットする。ステップＳ１７４２が否定判定されると、自車線内検知可能領域外の障害物が隣接車線に完全に移動したと推定し、ステップＳ１７４４に進む。ステップＳ１７４４では、反力制御指令値変化率ΔＦＡにΔＦＡ３(例えば５[kgf/s])をセットする。
【０１５１】
ステップＳ１７４１が否定判定されると、ステップＳ１７４５へ進む。ステップＳ１７４５では、ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔが所定時間Ｔ４（例えば２[sec]）よりも小さいか否かを判定する。ステップＳ１７４５が肯定判定されると、ステップＳ１７４６へ進み、反力減少の開始タイミングを所定時間Ｔ４だけ遅延させるように、反力制御指令値変化率ΔＦＡに０をセットする。ステップＳ１７４５が否定判定されると、ステップＳ１７４７へ進み、反力制御指令値変化率ΔＦＡにΔＦＡ４ (例えば３[kgf/s])をセットする。なお、反力制御指令値ΔＦＡ３，ΔＦＡ４は、上述した第１の実施の形態の運転操作反力補正処理（図１１のＳ７１０，Ｓ７１３）で用いた値と同じである。ただし、ΔＦＡ５≧ΔＦＡ６≧ΔＦＡ３≧ΔＦＡ４である。
【０１５２】
ステップＳ１７２０での運転操作反力補正処理Ａ、またはステップＳ１７４０での運転操作反力補正処理Ｂにおいて、反力制御指令値変化率ΔＦＡを設定したのち、ステップＳ１７０４へ移行する。
【０１５３】
ステップＳ１７０４では、前回設定した反力指令補正値ＦＡoutが、ステップＳ１７２０あるいはＳ１７４０で設定した反力制御指令値変化率ΔＦＡよりも大きいか否かを判定する。ステップＳ１７０４が肯定判定されると、ステップＳ１７０５に進み、ロスト経過時間カウンタＣｎｔ＿ｌｏｓｔを１だけ加算する。さらに、前回の反力指令補正値ＦＡoutから反力制御指令値変化率ΔＦＡを減じた値を、新たな反力指令補正値ＦＡoutに設定する。ステップＳ１７０４が否定判定されると、ステップＳ１７０６へ進む。ステップＳ１７０６では、反力指令補正値ＦＡoutを０に設定する。
このようにステップＳ１７００で反力指令補正値ＦＡoutを算出した後、ステップＳ１８００へ進む。
【０１５４】
ステップＳ１８００では、ステップＳ１７００で算出した反力指令補正値ＦＡoutをアクセルペダル反力制御装置６０へ出力し、今回の処理を終了する。
【０１５５】
図３５に、運転者の意図に応じた操作反力ＦＡの変化を模式的に示す。図３５の横軸は時間ｔを示し、時間ｔｌにおいて前方障害物が自車線あるいは検知可能領域から離脱し、反力制御の対象外となったとする。
【０１５６】
運転者意図が追い越し（flgAIM=1）である場合は、追い越し操作を容易に行えるように、反力制御指令値変化率ΔＦＡ５で操作反力ＦＡを速やかに減少させていく。運転者意図が追走（flgAIM=2）あるいは巡航（flgAIM=0）である場合は、前方障害物が対象外となった時間ｔｌで操作反力ＦＡが急に変化しないように、反力制御指令値変化率ΔＦＡ６，ΔＦＡ８で操作反力ＦＡを徐々に減少させていく。また、運転者意図が非加速（flgAIM=3）である場合は、反力制御指令値変化率ΔＦＡ７で、操作反力ＦＡをゆっくりと減少させて運転者の加速操作を抑制する。
【０１５７】
このように、以上説明した第２の実施の形態においては、以下のような作用効果を奏することができる。
（１）障害物が対象外となった場合に、ドライバー意図推定部５８Ａによって推定された運転者の意図を加味してペダル反力の変化パターンを補正する。これにより、前方車両との車間距離に応じてペダル反力ＦＡが増加している状態で前方車両が存在しなくなる場合に、ペダル反力の変化を効果的に補正し、運転者の違和感をより一層低減させることができる。
（２）ドライバー意図推定部５８Ａは、車線認識カメラ４０によって検出した道路状況と、走行位置認識部５７Ａによって検出した自車両の走行位置とに基づいて運転者の意図を推定するので、運転者の意図を正確に推定することができる。
（３）ドライバー意図推定部５８Ａは、自車両が一定車線内を走行中か、車線を変更中であるかを推定し、この推定結果と、レーザレーダ１０からの信号とに基づいて、障害物が対象外となった場合の運転者の意図を推定する。これにより、障害物が対象外となった原因が、障害物の挙動によるものか、運転者の意図によるものかといった観点から、運転者の意図をより正確に推定することができる。
（４）操作反力補正部５６Ａは、障害物が、（ａ）検知可能領域内で非検知になった場合は、第５の減少パターンで、（ｄ）自車線内の検知可能領域外に離脱した場合（flgSTATE=40）は、第６の減少パターンで、（ｂ）検知可能領域の右方車線、あるいは左方車線に離脱した場合（flgSTATE=20,30）、あるいは（ｃ）検知可能領域の遠方に離脱した場合（flgSTATE=10）は、運転者意図に応じた減少パターンでアクセルペダル反力ＦＡを低下させる。これにより、障害物が対象外となったときの障害物状態と運転者意図とを考慮するため、運転者の違和感を効果的に低減したペダル反力制御を行うことができる。前方障害物が検知可能領域の遠方、あるいは左右方向へ離脱したことが検出された場合には，障害物に対するリスクポテンシャルは小さいと考えられる。そこで、ペダル反力ＦＡの減少パターンを運転者意図に基づいて設定することにより、運転者の意図にあった反力制御を行うことができる。
（５）（ａ）検知可能領域内で非検知になったと判断された場合は、自車線前方に障害物が存在するにもかかわらず、レーザレーダ１０の一時的な性能低下や勾配等により非検知になった可能性がある。そこでで所定時間Ｔ４だけ遅延させた後、ゆっくりした速度（第５の速度）ΔＦＡ４で徐々にペダル反力ＦＡを低下させる。（ｄ）自車線内の検知可能領域外に離脱したと判断された場合は、例えば障害物が自車線外に離脱するまでの推定時間として設定した所定時間Ｔ３だけ遅延させた後、ΔＦＡ４よりも速い速度（第６の速度）ΔＦＡ３で、徐々にペダル反力ＦＡを低下させる。遅延時間Ｔ３，Ｔ４を設けることにより障害物が対象外になった場合でも、運転者は余裕を持ってシステムの状況を判断し、適切な操作を行うことができる。また、障害物が自車線外に離脱したと推定される時間を所定時間Ｔ３と設定すれば、ペダル反力ＦＡの減少開始タイミングが必要以上に遅延されることがなく、運転者の感覚に合った反力制御を行うことができる。
（６）ドライバー意図推定部５８Ａは、障害物が、（ｂ）検知可能領域の右方車線、あるいは左方車線に離脱した場合、あるいは（ｃ）検知可能領域の遠方に離脱した場合の運転者の意図を、（Ａ）現在の走行状態を維持する巡航、（Ｂ）障害物の追い越し、（Ｃ）障害物についていく追走、（Ｄ）非加速、のいずれかと推定する。操作反力補正部５６Ａは、運転者の意図が、（Ａ）巡航の場合は、第７の減少パターンで、（Ｂ）追い越しの場合は、第８の減少パターンで、（Ｃ）追走の場合は、第９の減少パターンで、（Ｄ）非加速の場合は、第１０の減少パターンでアクセルペダル反力ＦＡを低下させる。これにより、精度よく推定した運転者の意図に応じて、効果的なペダル反力制御を行うことができる。
（７）運転者の意図が（Ａ）巡航の場合は、運転者に追い越しや追走の意図がなく現在の走行状態を維持しようとする意図があると判断する。そこで、急にペダル反力を減少せず、安定した巡航走行を維持し易いようにペダル反力ＦＡをΔＦＡ８（第７の速度）で徐々に低下する。（Ｂ）追い越しの場合は、運転者に積極的に加速する意図があると判断する。そこで、ペダル反力を素早く低下させ、運転者の操作を確実に車両挙動に反映させるように、ペダル反力ＦＡをΔＦＡ８よりも速い速度（第８の速度）ΔＦＡ５で徐々に低下する。（Ｃ）追走の場合は、ペダル反力ＦＡをΔＦＡ８よりも速い速度（第９の速度）ΔＦＡ６で徐々に低下する。（Ｄ）非加速の場合は、自車両が追い越し車線から走行車線へ移動した状態で、追い越し車線を走行中の車両を走行車線側から追い越すような、好ましくない状況になりつつあると判断する。そこで、運転者による加速操作を抑制して追い越し行為を抑制するため、ペダル反力ＦＡをゆっくりした速度（第１０の速度）ΔＦＡ７で徐々に低下する。ここで、ΔＦＡ５≧ΔＦＡ６≧ΔＦＡ８≧ΔＦＡ７を満たすように反力制御指令値変化率ΔＦＡを設定するので、運転者の意図にあった効果的な反力制御を行うことができる。また、ΔＦＡ５≧ΔＦＡ６≧ΔＦＡ３≧ΔＦＡ４を満たすように反力制御指令値変化率ΔＦＡを設定することにより、運転者の意図にあった効果的な反力制御を行うことができる。
【０１５８】
なお、上述した第１および第２の実施の形態では、反力制御指令値ＦＡを所定の減少パターン（反力制御指令値変化率ΔＦＡ）で減少させているが、例えばステップ状に減少させたり、曲線的に減少させることもできる。また、減少パターン（反力制御指令値変化率ΔＦＡ）を、例えば反力制御指令値ＦＡが所定値、例えば０となるまでの時間に応じて決定することもできる。つまり、障害物が対象外となってから所定時間後にペダル反力ＦＡが所定値以下になるように、反力制御指令値変化率ΔＦＡを設定する。障害物が対象外となったときの反力制御指令値ＦＡｄ、反力制御指令値ＦＡが所定時間Ｔｄ後に０になるとすると、反力制御指令値変化率ΔＦＡは、以下の（式６４）で算出することができる。
【数６５】
ΔＦＡ＝ＦＡｄ／Ｔｄ （式６４）
【０１５９】
このように障害物が対象外となったときのペダル反力の大きさに応じて、操作反力を低下させる際の減少パターンを変更するので、例えば、前方車両との車間距離に応じてペダル反力が増加している状態で前方車両が存在しなくなった場合に、速やかにペダルの反力を低下させることができ、運転者の感覚に合った反力制御を行うことができる。障害物が対象外となってから所定時間後にペダル反力が所定値以下になるように減少パターンを変更するので、障害物が対象外となったときのペダル反力の大きさにかかわらず、ペダル反力が所定値に低下するまでの時間が等しくなり、より運転者の感覚に合った反力制御を行うことができる。
【０１６０】
なお、上述した実施の形態においては、前方障害物に対するリスクポテンシャルＲＰに応じてアクセルペダル反力制御を行ったが、これには限らず、ブレーキペダル反力制御を行うこともできる。また、リスクポテンシャルＲＰの算出方法は上述した実施の形態には限定されず、例えば車間距離を自車速あるいは先行車速で除した車間時間ＴＨＷの関数を用いたり、余裕時間ＴＴＣの関数と車間時間ＴＨＷの関数とを組み合わせてリスクポテンシャルＲＰを算出することもできる。リスクポテンシャルＲＰに対するアクセルペダル反力制御指令値ＦＡの特性も、図５には限定されない。
【０１６１】
上述した実施の形態において、レーザレーダ１０による検知可能領域の算出方法および障害物状態の判断方法について数式を用いて説明したが、障害物が自車線外あるいは検知可能領域外へと離脱して対象外となるときの状態を精度よく推定することができれば、上述した方法には限定されない。
【０１６２】
さらに、障害物状態を、遠方への離脱、右側あるいは左側車線への離脱、自車線内検知可能領域外への離脱のいずれかとして推定し、運転者の意図を、巡航、追走、追い越しおよび非加速のいずれかとして推定した。しかし、これには限定されず、他の障害物状態や運転者意図を設定し、それらに応じてペダル反力の減少パターンを設定することもできる。
【０１６３】
上記実施の形態においては、障害物検出手段としてレーザレーダ１０、車速センサ２０および操舵角センサ３０を用い、操作反力発生手段として、アクセルペダル反力制御装置６０を用い、道路状況認識手段として車線認識カメラ４０を用いた。ただし、これらには限定されず、例えば障害物検出手段としてレーザレーダ１０の代わりに別方式のミリ波レーダ等や、ＣＣＤあるいはＣＭＯＳカメラを用いることもできる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態による車両用運転操作補助装置のシステム図。
【図２】図１に示す車両用運転操作補助装置を搭載した車両の構成図。
【図３】コントローラの内部構成を示すブロック図。
【図４】第１の実施の形態のコントローラにおける運転操作補助制御処理の処理手順を示すフローチャート。
【図５】前後方向リスクポテンシャルに対するアクセル制御反力指令値の特性を示すマップ。
【図６】直線路における検知可能領域の算出方法を説明する図。
【図７】曲線路における検知可能領域の算出方法を説明する図。
【図８】障害物状態推定処理で行う処理の処理手順を示すフローチャート。
【図９】直線路における障害物状態の推定方法を説明する図。
【図１０】曲線路における障害物状態の推定方法を説明する図。
【図１１】運転操作反力補正処理で行う処理の処理手順を示すフローチャート。
【図１２】第２の実施の形態による車両用運転操作補助装置の構成を示すシステム図。
【図１３】図１に示す車両用運転操作補助装置を搭載した車両の構成図。
【図１４】コントローラの内部構成を示すブロック図。
【図１５】第２の実施の形態のコントローラにおける運転操作補助制御処理の処理手順を示すフローチャート。
【図１６】直線路における検知可能領域の算出方法及び障害物状態の推定方法を説明する図。
【図１７】曲線路における検知可能領域の算出方法及び障害物状態の推定方法を説明する図。
【図１８】障害物状態推定処理で行う処理の処理手順を示すフローチャート。
【図１９】ドライバー意図推定処理で行う処理の処理手順を示すフローチャート。
【図２０】（ａ）〜（ｄ） ドライバー意図の推定方法を説明する図。
【図２１】ドライバー意図判別処理Ａ１における処理手順を示すフローチャート。
【図２２】ドライバー意図判別処理Ａ２における処理手順を示すフローチャート。
【図２３】ドライバー意図判別処理Ｂ１における処理手順を示すフローチャート。
【図２４】ドライバー意図判別処理Ｂ２における処理手順を示すフローチャート。
【図２５】運転意図が巡航の場合の走行状態を示す図。
【図２６】運転意図が巡航の場合の走行状態を示す図。
【図２７】運転意図が巡航の場合の走行状態を示す図。
【図２８】運転意図が追い越しの場合の走行状態を示す図。
【図２９】運転意図が追走の場合の走行状態を示す図。
【図３０】運転意図が追い越しの場合の走行状態を示す図。
【図３１】運転意図が非加速の場合の走行状態を示す図。
【図３２】運転操作反力補正処理における処理手順を示すフローチャート。
【図３３】運転操作反力補正処理Ａにおける処理手順を示すフローチャート。
【図３４】運転操作反力補正処理Ｂにおける処理手順を示すフローチャート。
【図３５】障害物が対象外となってからの操作反力の変化を模式的に示す図。
【符号の説明】
１０：レーザレーダ
２０：車速センサ
３０：操舵角センサ
４０：車速センサ
５０，５０Ａ：コントローラ
６０：アクセルペダル反力制御装置
７０：サーボモータ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving assist system for a vehicle that assists a driver's operation.
[0002]
[Prior art]
A conventional vehicle driving assist system changes the operation reaction force of an accelerator pedal based on the inter-vehicle distance between a preceding vehicle and the host vehicle (for example, Patent Document 1). This device draws the driver's attention by increasing the reaction force of the accelerator pedal as the inter-vehicle distance decreases.
Prior art documents related to the present invention include the following.
[Patent Document 1]
JP-A-10-166890
[Patent Document 2]
JP-A-10-166889
[0003]
[Problems to be solved by the invention]
However, the driving assist system for a vehicle as described above requires an accelerator when the preceding vehicle which is the target of the reaction force control moves to an adjacent lane, or when the own vehicle changes lanes and the preceding vehicle is no longer detected. There has been a problem that the pedal reaction force changes suddenly, giving the driver an uncomfortable feeling.
[0004]
[Means for Solving the Problems]
A vehicle driving assist system according to the present invention calculates an obstacle potential of an own vehicle with respect to an obstacle based on a signal from the obstacle detecting means for detecting an obstacle existing around the own vehicle and an obstacle detecting means. A risk potential calculating means, an operation reaction force determining means for determining an operation reaction force to be generated in the vehicle operating device according to a preset change pattern based on a signal from the risk potential calculating means, and an operation reaction force determining means. An operation reaction force generating means for generating an operation reaction force on the vehicle operation device based on the signal, and an operation reaction force for correcting a change pattern when an obstacle detected by the obstacle detection means is excluded from the target. Correction means.
[0005]
【The invention's effect】
According to the present invention, when an obstacle around the own vehicle is excluded from the target, the change pattern of the operation reaction force generated in the vehicle device is corrected according to the risk potential, so that even if the obstacle suddenly disappears, Variations in the operation reaction force can be suppressed.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
<< 1st Embodiment >>
A vehicle driving assist system according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing the configuration of the vehicle driving assist system 1 according to the first embodiment, and FIG. 2 is a configuration diagram of a vehicle equipped with the vehicle driving assist system 1.
[0007]
First, the configuration of the vehicle driving assist system 1 will be described. The laser radar 10 is attached to a front grill portion or a bumper portion of a vehicle, and scans an infrared light pulse in a horizontal direction. The laser radar 10 measures a reflected wave of an infrared light pulse reflected by a reflector ahead (usually, a rear end of a forward vehicle), and calculates a vertical distance to an obstacle ahead from the arrival time of the reflected wave. Detect lateral distance. The detected vertical distance and horizontal distance are output to the controller 50. The forward area scanned by the laser radar 10 is about ± 6 [deg] with respect to the front of the own vehicle, and a forward object existing within this range is detected.
[0008]
The vehicle speed sensor 20 detects the vehicle speed of the host vehicle by measuring the number of rotations of wheels and the number of rotations on the output side of the transmission. The detected vehicle speed is output to the controller 50.
[0009]
The steering angle sensor 30 detects a steering angle from a rotational displacement of the steering wheel 110 or a steering shaft (not shown) that rotates integrally with the steering wheel 110. The steering angle sensor 30 includes, for example, an amplifier such as a gear mechanism and an angle detection mechanism such as a rotary encoder or a potentiometer. After the rotational displacement of the steering wheel 110 is amplified by the gear mechanism, the steering angle is detected as a steering angle detection signal by the angle detection mechanism. I do. The detected steering angle detection signal is output to the controller 50.
[0010]
The controller 50 is composed of a CPU and CPU peripheral parts such as a ROM and a RAM, and the obstacle recognition unit 51, the risk potential calculation unit 52, the driving reaction force, as shown in FIG. The determination unit 53, the detectable area calculation unit 54, the obstacle state estimation unit 55, and the driving operation reaction force correction unit 56 are configured.
[0011]
The controller 50 estimates the road shape from the vehicle speed input from the vehicle speed sensor 20 and the steering angle input from the steering angle sensor 30. Further, an obstacle situation in front of the own vehicle is detected from the vertical distance and the horizontal distance input from the laser radar 10 and the estimated road shape. The controller 50 calculates a risk potential of the own vehicle with respect to the obstacle based on the detected obstacle situation. Further, the controller 50 performs control according to the risk potential as follows from the risk potential for the obstacle.
[0012]
The vehicle driving assist system 1 according to the first embodiment of the present invention appropriately assists the driving operation of the driver by controlling the reaction force generated when the accelerator pedal is operated. Therefore, the controller 50 calculates a reaction force control amount in the vehicle longitudinal direction based on the calculated risk potential. The controller 50 outputs the calculated longitudinal reaction force control amount to the accelerator pedal reaction force control device 60.
[0013]
The accelerator pedal reaction force control device 60 controls the torque generated by the servomotor 61 incorporated in the link mechanism of the accelerator pedal 62 according to the reaction force control amount output from the controller 50. The servomotor 61 controls a torque and a rotation angle generated according to a command value from the accelerator pedal operation reaction force control device 60, and arbitrarily controls an operation reaction force generated when the driver operates the accelerator pedal 62. can do.
[0014]
The obstacle recognition unit 51 of the controller 50 shown in FIG. 3 reads the signal from the laser radar 10 and calculates the position, the moving speed, and the moving direction of the obstacle ahead. The risk potential calculation unit 52 calculates the risk potential of the own vehicle with respect to the forward obstacle based on the signal from the obstacle recognition unit 51. The driving operation reaction force determination unit 53 calculates a reaction force control amount in the front-rear direction from the risk potential calculated by the risk potential calculation unit 52.
[0015]
The detectable area calculation unit 54 calculates a detectable area in the own lane by the laser radar 10 from the own vehicle speed input from the vehicle speed sensor 20 and the steering angle input from the steering angle sensor 30. The obstacle state estimating unit 55 calculates, based on the position, the moving speed, and the moving direction of the forward obstacle calculated by the obstacle recognizing unit 51 and the detectable area in the own lane calculated by the detectable area calculating unit 54, Estimate how the obstacle moves in the detectable area in the own lane.
[0016]
Based on the movement of the obstacle estimated by the obstacle state estimating unit 55, the driving operation reaction force correcting unit 56 controls the driving operation reaction force determining unit 53 according to the state when the obstacle is excluded from the target. The calculated reaction force control amount is corrected. Here, a state in which the obstacle has departed from the lane or the detectable area of the radar and is no longer an obstacle to be subjected to the accelerator pedal reaction force control is excluded from the subject.
[0017]
Next, the operation of the vehicle driving assist system 1 according to the embodiment of the present invention will be described in detail. FIG. 4 is a flowchart showing a processing procedure of a driving operation assisting control process in controller 50 according to the embodiment of the present invention. This processing is continuously performed at regular intervals, for example, every 50 [msec].
[0018]
First, the running state is read in step S100. Here, the traveling state is information on the traveling state of the own vehicle including the obstacle state ahead of the own vehicle. Therefore, a forward obstacle detected by the laser radar 10, for example, a vertical distance and a lateral distance to a vehicle traveling ahead of the own vehicle, a traveling vehicle speed of the own vehicle detected by the vehicle speed sensor 20, and a steering angle sensor 30 are used. Read the detected steering angle.
[0019]
In step S200, the state of the obstacle ahead is recognized based on the traveling state data read and recognized in step S100. Here, the relative position of the forward obstacle with respect to the own vehicle, the moving direction and the moving speed thereof, and the current traveling state data obtained in step S100, which are detected before the previous processing cycle and stored in the memory of the controller 50, Thus, the current relative position of the obstacle ahead of the host vehicle with respect to the own vehicle and the moving direction and moving speed thereof are recognized. Here, the vertical distance, the horizontal distance, the vertical relative speed, and the horizontal relative speed of the front obstacle with respect to the own vehicle are recognized. Then, it recognizes how the obstacle is located in front of the own vehicle and moves relatively to the own vehicle. Note that the longitudinal direction is defined as the longitudinal direction of the vehicle, and the lateral direction is defined as the lateral direction of the vehicle.
[0020]
In step S300, a risk potential RP for the forward obstacle is calculated. In order to calculate the risk potential RP for the forward obstacle, first, a time to collision (TTC: Time To Collision) for the recognized forward obstacle is calculated. Here, the allowance time TTC for a forward obstacle is obtained by the following (Equation 1).
(Equation 1)
TTC = y / Vr (Equation 1)
Here, y: the relative distance from the host vehicle to the obstacle ahead, Vr: the relative speed of the obstacle ahead to the host vehicle, respectively. The allowance time TTC is a physical quantity that indicates the current degree of approach of the host vehicle to the obstacle in front, and when the current driving situation continues, that is, when the relative vehicle speed Vr is constant, the host vehicle and the obstacle will be displayed after a few seconds. This is a value indicating whether the contact is made.
[0021]
Using the calculated margin time TTC, a risk potential RP with respect to the obstacle ahead is calculated. The risk potential RP for the obstacle ahead is calculated by the following (Equation 2).
(Equation 2)
RP = 1 / TTC (Equation 2)
[0022]
As shown in (Equation 2), the risk potential RP is expressed as a function of the time to contact TTC using the reciprocal of the time to contact TTC. The greater the risk potential RP, the greater the degree of approach to the obstacle ahead. Note that the risk potential RP is a risk potential for a vehicle traveling ahead, and indicates a risk potential in the longitudinal direction of the own vehicle.
[0023]
In step S400, a longitudinal control command value, that is, a reaction force control command value FA to be output to the accelerator pedal reaction force control device 60 is calculated from the longitudinal risk potential RP calculated in step S300. As the risk potential RP in the front-rear direction increases, a control reaction force is generated in a direction in which the accelerator pedal 62 is returned.
[0024]
FIG. 5 shows the relationship between the longitudinal risk potential RP and the accelerator pedal reaction force control command value FA. As shown in FIG. 5, when the longitudinal risk degree RP is smaller than a predetermined value RPmax, the accelerator pedal reaction force control command value FA is calculated so as to generate a larger accelerator pedal reaction force as the longitudinal risk potential RP increases. I do. When the longitudinal risk potential RP is larger than the predetermined value RPmax, the accelerator pedal reaction force control command value FA is fixed at the maximum value FAmax so as to generate the maximum accelerator pedal reaction force.
[0025]
In step 500, a detectable area in the own lane is calculated from a forward area scanned by the laser radar 10 (for example, ± 6 [deg] with respect to the front of the own vehicle). The detectable area in the own lane is calculated as follows according to, for example, the shape of the road on which the own vehicle travels. In the following calculations, it is assumed that the laser 10 is mounted at the front center of the host vehicle, and that the host vehicle is running in the center of the host vehicle lane.
[0026]
FIG. 6 shows the relationship between the host vehicle traveling on a straight road and the detectable area of the laser radar 10. FIG. 7 shows the relationship between the vehicle traveling on a curved road and the detectable area of the laser radar 10. In FIG. 6 and FIG. 7, a coordinate system is set with the center position on the front of the host vehicle as the origin, the y-axis in the vehicle front-rear direction, and the x-axis in the vehicle left-right direction. The forward direction of the vehicle is the + y direction, and the right direction of the vehicle is the + x direction. The scanning width of the laser radar 10 is 2θ, the longest detection distance of the laser radar 10 in the vehicle longitudinal direction is ymax, and the lane width is 2D.
[0027]
《On a straight road》
First, a method of calculating the detectable area of the laser radar 10 when the vehicle travels on a straight road will be described with reference to FIG.
The right boundary of the radar scan range can be expressed as (Equation 3).
[Equation 3]
y = x / tanθ (Equation 3)
Therefore, the intersection (x1, y1) between the right end of the own lane and the right boundary of the radar scan range is expressed as (Expression 4) and (Expression 5).
(Equation 4)
x1 = D (Equation 4)
(Equation 5)
y1 = D / tanθ (Equation 5)
[0028]
Similarly, the left boundary of the radar scan range can be expressed as (Equation 6).
(Equation 6)
y = −x / tan θ (Equation 6)
Thereby, the intersection (x2, y2) between the left end of the own lane and the left boundary of the radar scan range is expressed as (Equation 7) (Equation 8).
(Equation 7)
x2 = −D (Equation 7)
(Equation 8)
y2 = D / tanθ (Equation 8)
[0029]
From these, the detectable area in the own lane for a straight road is set as follows.
(1) When ymax ≧ y ≧ y1 (= y2), that is, when the distance y between the obstacle and the host vehicle is y1 or y2 or more.
(Equation 9)
D ≧ x ≧ −D (Equation 9)
[0030]
(2) When y1 (= y2)> y (> 0), that is, when the distance y between the obstacle and the host vehicle is smaller than y1 or y2
(Equation 10)
y · tan θ ≧ x ≧ −y · tan θ (Equation 10)
[0031]
《Curved road》
Next, a method of calculating the detectable area of the laser radar 10 when the vehicle travels on a curved road will be described with reference to FIG. Here, a left curve will be described as an example.
[0032]
The radius of curvature R of the lane is calculated using the vehicle speed V from the vehicle speed sensor 20, the steering angle STR input from the steering angle sensor 30, the steering gear ratio STR_GR, the wheelbase l, and the stability factor A (Equation 11). ). Here, the steering gear ratio STR_GR is the reduction ratio of the steering gear, the wheelbase l is the length of the center axle of the front and rear axles, and the stability factor A is a value indicating the steering characteristics of the vehicle. These are stored in the memory of the controller 50.
[Equation 11]
R = (1 + A · V ^Two ) · L · STR_GR / STR (Equation 11)
[0033]
The right end of the own lane of a curved road having a radius of curvature R is represented as (Equation 12).
(Equation 12)
y = √ ｛(R + D) ^Two − (X + R) ^Two ｝ (Equation 12)
[0034]
The intersection (x1, y1) between the right boundary of the radar scan range and the right end of the own lane is calculated by simultaneously calculating (Equation 3) and (Equation 12), thereby obtaining (Equation 13) and (Equation 14). Is represented as
(Equation 13)

[Equation 14]

[0035]
Similarly, the intersection (x2, y2) between the left boundary of the radar scan range and the right end of the own lane is calculated by simultaneously calculating (Equation 6) and (Equation 12), thereby obtaining the following (Equation 15) ( It is expressed as in equation 16).
(Equation 15)

(Equation 16)

[0036]
From these, the detectable area in the own lane on a curved road is set as follows. Is
(1) When y2 ≧ y ≧ y1 and ymax ≧ y, that is, when the distance y between the obstacle and the host vehicle is not less than y1 and not more than y2 and not more than the longest detection distance ymax of the laser radar 10.
[Equation 17]
√ ｛(R + D) ^Two -Y ^Two ｝ −R ≧ x ≧ −y · tan θ (Equation 17)
[0037]
(2) When y1> y (> 0), that is, when the distance y between the obstacle and the host vehicle is smaller than y1
(Equation 18)
y · tan θ ≧ x ≧ −y · tan θ (Equation 18)
In the case of the right curve, the detectable area in the own lane can be calculated in the same manner as in the case of the left curve.
[0038]
Here, the road shape is estimated from the vehicle speed V and the steering angle STR. However, the present invention is not limited to this. For example, a white image is recognized by performing image processing on a camera image of a scene in front of the vehicle or obtained from a navigation system. The road shape can also be estimated based on the road information obtained.
After calculating the detectable area in step S500, the process proceeds to step S600 in FIG.
[0039]
In step S600, the obstacle is determined based on the relative position of the current obstacle recognized in step S200 with respect to the own vehicle, the moving direction and speed thereof, and the detectable area in the own lane calculated in step S500. Is estimated how to move in the detectable area in the inside. The processing performed in step S600 will be described with reference to the flowchart in FIG.
[0040]
In step S601, it is determined whether the laser radar 10 has detected an obstacle ahead. If step S601 is affirmed, the process proceeds to step S602.
[0041]
In step S602, it is determined whether or not the front obstacle is moving far away. If an affirmative determination is made in step S602, the flow advances to step S603 to set 1 to an obstacle state flag flgSTATE. If a negative determination is made in step S602, the process proceeds to step S604.
[0042]
In step S604, it is determined whether or not the front obstacle is moving to the adjacent lane. If an affirmative determination is made in step S604, the process proceeds to step S605, in which the obstacle state flag flgSTATE is set to 2 and the processing ends. If a negative determination is made in step S604, the process proceeds to step S606.
[0043]
In step S606, it is determined whether or not the front obstacle is moving from inside the detectable area in the own lane to outside the detectable area. If an affirmative determination is made in step S606, the process proceeds to step S607, in which the obstacle state flag flgSTATE is set to 3, and the process ends. If a negative determination is made in step S606, the process proceeds to step S608, in which the obstacle state flag flgSTATE is set to 4, and the process ends.
[0044]
If a negative determination is made in step S601 and a forward obstacle has not been detected, the process proceeds to step S609. In step S609, it is determined whether or not the accelerator pedal reaction force control command correction value FAout calculated in the previous cycle (calculated in S700) is 0. The accelerator pedal reaction force control command correction value FAout will be described later. If an affirmative determination is made in step S609, the process proceeds to step S610, where the obstacle state flag flgSTATE is cleared to 0, and the process ends. On the other hand, if the determination in step S609 is negative and the reaction force command correction value FAout is not 0, the obstacle state flag flgSTATE set in the previous cycle is used as it is.
[0045]
The determination of whether or not the preceding obstacle is moving out of the detectable area in the distant, adjacent lane, or own lane in steps S602, S604, and S606 described above is performed for a predetermined time T0 (for example, T0 = 1). [sec]) can be performed based on the position of the obstacle after. These determination methods will be described with reference to FIGS. 9 and 10 for each road shape. FIG. 9 shows a case where the own lane is a straight road, and FIG. 10 shows a case where the own lane is a curved road. Here, the position of the forward obstacle is (x (0), y (0)), and the relative speed is (dx, dy).
[0046]
《On a straight road》
First, a method of determining in which direction the obstacle is moving in the case of a straight road will be described with reference to FIG.
The position (x (T0), y (T0)) of the obstacle ahead after the predetermined time T0 is expressed as (Equation 19) and (Equation 20).
[Equation 19]
x (T0) = x (0) + T0 · dx (Equation 19)
(Equation 20)
y (T0) = y (0) + T0 · dy (Equation 20)
[0047]
(A) Moving to a distant place (flgSTATE = 1)
(Equation 21)
dy> 0 (Equation 21)
(Equation 22)
y (T0) ≧ ymax (Equation 22)
When the traveling state of the front obstacle satisfies (Equation 21) and (Equation 22), that is, the vehicle speed of the front obstacle is higher than the own vehicle speed, and the vertical relative distance y (T0) after a predetermined time T0 is equal to the laser radar 10 Is larger than the maximum detection distance ymax, it can be determined that the forward obstacle is moving far away.
[0048]
(B) Moving to adjacent lane (flgSTATE = 2)
The moving path of the forward obstacle is represented by the following (Equation 23).
[Equation 23]
y = dy / dx ｛{xx (0)} + y (0) (formula 23)
Using the moving path of the front obstacle calculated by (Equation 23), it is determined whether the front obstacle is moving from the own lane to the adjacent lane.
[0049]
When dx> 0, that is, when the forward obstacle is relatively moving to the right of the vehicle
(Equation 24)
y1 <dy / dx ｛{x1-x (0)} + y (0) (Formula 24)
(Equation 25)
x (T0) ≧ x1 (Equation 25)
When the traveling state of the front obstacle satisfies (Equation 24) and (Equation 25), that is, the vertical relative distance to the front obstacle is larger than y1, and the horizontal relative distance x (T0) after a predetermined time T0 is x1. In the above case, it can be determined that the forward obstacle is moving to the right lane.
[0050]
When dx <0, that is, when the obstacle ahead is relatively moving to the left of the vehicle
(Equation 26)
y2 <dy / dx ｛{x2-x (0)} + y (0) (equation 26)
[Equation 27]
x (T0) ≦ x2 (Equation 27)
When the traveling state of the front obstacle satisfies (Equation 26) and (Equation 27), that is, the vertical relative distance to the front obstacle is larger than y2, and the horizontal relative distance x (T0) after a predetermined time T0 is x2. In the following cases, it can be determined that the forward obstacle is moving to the left lane.
[0051]
(C) Moving out of detectable area in own lane (flgSTATE = 3)
Using the moving path of the front obstacle calculated by the above (Equation 23), it is determined whether or not the front obstacle is moving from the detectable area in the own lane to the outside of the detectable area.
When dx> 0, that is, when the forward obstacle is relatively moving to the right of the vehicle
[Equation 28]
y1> dy / dx ｛{x1-x (0)} + y (0) (formula 28)
(Equation 29)
x (T0) ≧ y (T0) · tanθ (Equation 29)
When the traveling state of the front obstacle satisfies (Equation 28) and (Equation 29), that is, the vertical relative distance to the front obstacle is smaller than y1, and the horizontal relative distance x (T0) after a predetermined time T0 is the laser. In the case where the obstacle is outside the right boundary of the radar 10, it can be determined that the front obstacle is moving outside the detectable area on the right side in the own lane.
[0052]
When dx <0, that is, when the obstacle ahead is relatively moving to the left of the vehicle
[Equation 30]
y2> dy / dx ｛{x2-x (0)} + y (0) (formula 30)
[Equation 31]
x (T0) ≦ −y (T0) · tanθ (Equation 31)
When the traveling state of the front obstacle satisfies (Equation 30) and (Equation 31), that is, the vertical relative distance to the front obstacle is smaller than y2, and the horizontal relative distance x (T0) after a predetermined time T0 is the laser. If it is outside the left boundary of the radar 10, it can be determined that the forward obstacle is moving outside the detectable area on the left side of the own lane.
[0053]
《Curved road》
Next, a method of determining in which direction the obstacle is moving in the case of a curved road having a left curve will be described with reference to FIG.
The position (x (T0), y (T0)) of the front obstacle after the predetermined time T0 is expressed as in (Equation 19) and (Equation 20) described above. In addition, the moving path of the obstacle ahead is calculated by the above (Equation 23).
(D) Moving to a distant place (flgSTATE = 1)
(Equation 32)
dy> 0 (Equation 32)
[Equation 33]
y (T0) ≧ ymax (Equation 33)
When the traveling state of the front obstacle satisfies (Equation 32) and (Equation 33), that is, the vehicle speed of the front obstacle is higher than the own vehicle speed, and the vertical relative distance y (T0) after a predetermined time T0 is equal to the laser radar 10. Is larger than the maximum detection distance ymax, it can be determined that the forward obstacle is moving far away.
[0054]
(E) Moving to adjacent lane (flgSTATE = 2)
When dx> 0, that is, when the forward obstacle is relatively moving to the right of the vehicle
(Equation 34)
y1 <dy / dx ｛{x1-x (0)} + y (0) (Formula 34)
(Equation 35)
y (T0) ≧ √ ｛(R + D) ^Two − (X (T0) + R) ^Two ｝ (Equation 35)
When the traveling state of the front obstacle satisfies (Equation 34) and (Equation 35), that is, the vertical relative distance to the front obstacle is larger than y1, and the vertical relative distance y (t0) after a predetermined time T0 is a curve. If the road is outside the right end of the own lane, it can be determined that the forward obstacle is moving to the right lane.
[0055]
When dx <0, that is, when the obstacle ahead is relatively moving to the left of the vehicle
[Equation 36]
y2 <dy / dx ｛{x2-x (0)} + y (0) (Equation 36)
(37)
y (T0) ≧ √ ｛(R + D) ^Two − (X (T0) + R) ^Two ｝ (Equation 37)
When the running state of the forward obstacle satisfies (Expression 36) and (Expression 37), that is, the vertical relative distance to the forward obstacle is larger than y2, and the vertical relative distance y (T0) after a predetermined time T0 is a curve. If the road is outside the right end of the own lane, it can be determined that the front obstacle is moving to the right lane.
[0056]
(F) Moving out of the detectable area on the right in the own lane (flgSTATE = 3)
When dx> 0, that is, when the forward obstacle is relatively moving to the right of the vehicle
[Equation 38]
y1> dy / dx ｛{x1-x (0)} + y (0) (formula 38)
[Equation 39]
x (T0) ≧ y (T0) · tanθ (Equation 39)
When the traveling state of the front obstacle satisfies (Equation 38) and (Equation 39), that is, the vertical relative distance to the front obstacle is smaller than y1, and the horizontal relative distance x (T0) after a predetermined time T0 is the laser. When the obstacle is outside the right boundary of the radar 10, it can be determined that the forward obstacle is moving outside the detectable area on the right side in the own lane.
[0057]
(G) Moving outside the left detectable area in the own lane (flgSTATE = 3)
(Equation 40)
x (T0) ≦ −y (T0) · tanθ (Equation 40)
(Equation 41)
y (T0) ≦ √ ｛(R + D) ^Two − (X (T0) + R) ^Two 式 (Equation 41)
When the traveling state of the forward obstacle satisfies (Equation 40) and (Equation 41), that is, the lateral relative distance x (T0) after the predetermined time T0 is outside the left boundary of the laser radar 10, and after the predetermined time T0. When the vertical relative distance y (T0) is inside the right end of the own lane of the curved road, it can be determined that the front obstacle is moving outside the detectable area on the left side of the own lane.
After estimating the obstacle state in step S600 and setting the obstacle state flag flgSTATE, the process proceeds to step S700.
[0058]
In step S700, the reaction force control command value FA calculated in step S400 is corrected based on the movement of the obstacle estimated in step S600. That is, the reaction force command value change rate ΔFA is set in accordance with the state when the obstacle moves out of the detectable region and becomes out of the target, and the reaction force command correction value FAout is calculated. The correction of the reaction force command correction value FAout will be described in detail with reference to the flowchart of FIG.
[0059]
In step S701, the position (x (0), y (0)) of the forward obstacle detected by the laser radar 10 and the detectable area in the own lane set by (Equation 9) and (Equation 10) , It is determined whether or not the obstacle exists in the own lane. If step S701 is affirmed, the process proceeds to step S702. In step S702, the lost elapsed time counter Cnt_lost is cleared to 0, the reaction force control command value FA calculated in step S400 is set as the reaction force command correction value FAout, and the process ends. The lost elapsed time counter Cnt_lost indicates the elapsed time (lost elapsed time) from the point in time at which no obstacle in front was detected. If a negative determination is made in step S701, the process proceeds to step S703 in order to calculate the reaction force command correction value FAout according to the state of the obstacle at the time when the obstacle is out of the target.
[0060]
In step S703, it is determined whether the obstacle state flag flgSTATE set according to the flowchart in FIG. If the affirmative determination is made in step S703, it is determined that the forward obstacle has moved far away and is not a target, and the process proceeds to step S704. In step S704, ΔFA1 (for example, 10 [kgf / s]) is set to the reaction force control command value change rate ΔFA. If a negative determination is made in step S703, the process proceeds to step S705.
[0061]
In step S705, it is determined whether or not the obstacle state flag flgSTATE is 2. If step S705 is affirmatively determined, it is determined that the forward obstacle has moved to the adjacent lane and has been excluded from the target, and the process proceeds to step S706. In step S706, ΔFA2 (for example, 10 [kgf / s]) is set as the reaction force control command value change rate ΔFA. If a negative determination is made in step S705, the process proceeds to step S707.
[0062]
In step S707, it is determined whether or not the obstacle state flag flgSTATE is 3. If an affirmative determination is made in step S707, it is determined that the forward obstacle has moved outside the detectable area in the own lane, and the flow proceeds to step S708. In step S708, it is determined whether the lost elapsed time counter Cnt_lost is smaller than a predetermined time T3 (for example, 1 [sec]). The predetermined time T3 is set to an appropriate value in advance as a time required for the forward obstacle to move to the adjacent lane after moving out of the detectable area in the own lane. The predetermined time T3 may be calculated from the position and the relative speed at the time when the obstacle is not detected, until the vehicle leaves the lane, and may be set as the predetermined time T3.
[0063]
If a positive determination is made in step S708 and the lost elapsed time is shorter than the predetermined time T3, the process proceeds to step S709. In step S709, the reaction force control command value change rate ΔFA is set to 0 so that the start timing of the reaction force decrease is delayed by a predetermined time T3. On the other hand, when the lost elapsed time is equal to or longer than the predetermined time T3, the process proceeds to step S710. In step S710, ΔFA3 (for example, 5 [kgf / s]) is set as the reaction force control command value change rate ΔFA. In this way, when the forward obstacle moves out of the detectable area in the own lane, the lost elapsed time is measured to estimate whether or not the forward obstacle has completely moved to the adjacent lane. After determining that the vehicle has left the lane, the reaction force control command value is corrected.
[0064]
If a negative determination is made in step S707, it is determined that the obstacle in the own lane has suddenly been undetected due to the gradient of the road or the like, and the process proceeds to step S711. In step S711, it is determined whether or not the lost elapsed time counter Cnt_lost is smaller than a predetermined time T4 (for example, 2 [sec]). If the determination in step S711 is affirmative, the process proceeds to step S712, in which the reaction force control command value change rate ΔFA is set to 0 so that the reaction force start timing is delayed by a predetermined time T4. If a negative determination is made in step S711, the process proceeds to step S713, in which the reaction force control command value change rate ΔFA is set to ΔFA4 (for example, 3 [kgf / s]). As described above, when the obstacle in the own lane is not detected suddenly, the reaction force control command value is not corrected until the predetermined time T4 has elapsed.
[0065]
After setting the reaction force control command value change rate ΔFA as described above, the process proceeds to step S714. In step S714, it is determined whether or not the reaction force command correction value FAout set in the previous cycle is greater than the reaction force control command value change rate ΔFA. If step S714 is affirmed, the process proceeds to step S715. In step S715, the lost elapsed time counter Cnt_lost is incremented by one. Further, a value obtained by subtracting the reaction force control command value change rate ΔFA from the reaction force command correction value FAout set in the previous cycle is set as a new reaction force command correction value FAout.
[0066]
On the other hand, if a negative determination is made in step S714, the process proceeds to step S716. In step S716, the reaction force command correction value FAout is set to 0 because the previous reaction force command correction value FAout is already smaller than the reaction force control command value change rate ΔFA.
[0067]
After setting the reaction force command correction value FAout in step S700, the process proceeds to step S800. In step S800, the reaction force command correction value FAout calculated in step S700 is output to accelerator pedal reaction force control device 60, and the current process ends.
[0068]
Thus, in the first embodiment described above, the following operational effects can be obtained.
(1) When the obstacle detected by the laser radar 10 is out of the detectable area or out of the own lane and becomes a target, the change pattern of the operation reaction force generated on the accelerator pedal 62 is corrected. . Thus, for example, when the front vehicle stops existing in a state where the pedal reaction force FA is increasing in accordance with the inter-vehicle distance to the front vehicle, the change in the pedal reaction force FA is suppressed, and the driver's discomfort is reduced. can do.
(2) When the obstacle is out of scope, the pedal reaction force FA is delayed after being delayed for a predetermined time and then reduced, so that the change in the pedal reaction force FA can be suppressed, and the driver's discomfort can be reduced.
(3) Since the pedal reaction force FA is gradually reduced when the obstacle is out of scope, it is possible to suppress a change in the pedal reaction force FA and to reduce the driver's discomfort.
(4) The obstacle recognition unit 51 recognizes a traveling situation such as how the obstacle is moving, and the obstacle state estimation unit 55 estimates an obstacle state when the obstacle is out of the target. The operation reaction force correction unit 56 corrects the change pattern of the pedal reaction force FA based on the estimation result of the obstacle state, and thus can perform pedal reaction force control that matches the driver's feeling.
(5) The obstacle state estimating unit 55 calculates the detectable area in the own lane which can be detected by the laser radar 10 and the signal from the obstacle recognizing unit 51, which is calculated by the detectable area calculating unit 54. Estimate the obstacle state when the obstacle is out of the target. As a result, the state of the obstacle can be more accurately estimated, and pedal reaction force control suited to the driver's feeling can be performed.
(6) The obstacle state estimating unit 55 detects the obstacle state when the obstacle is out of the target in the (a) non-detectable area within the detectable area (flgSTATE = 4) and (b) the detectable state. Departed to the right lane or left lane of the area (flgSTATE = 2), (c) departed far from the detectable area (flgSTATE = 1), (d) departed outside the detectable area in the own lane (FlgSTATE = 3). In the case where the obstacle is not detected in the (a) detectable area, the first decrease pattern is used, and in the case where the obstacle has left in the right or left lane of the detectable area, the second is used. In the decrease pattern of (c), when the vehicle departs far away from the detectable area, the pedal decreases in the third decrease pattern, and when the vehicle departs out of the detectable area in the own lane, the pedal decreases in the fourth decrease pattern. Decrease the reaction force. Thereby, it is possible to perform a reaction force control suitable for the driver's sense according to the obstacle state when the obstacle is out of the target.
(7) (a) If it is determined that the detection has not been performed in the detectable area, the obstacle is present due to a temporary performance drop or a gradient of the laser radar 10 despite the presence of an obstacle in front of the own lane. Is delayed for a predetermined time T4, and then the pedal reaction force FA is gradually reduced at a reduced speed (first speed) ΔFA4. By providing the predetermined delay time T4 in this way, even if there is an obstacle in the own lane, the driver can judge the system situation with a margin and perform an appropriate operation. Further, even when there is no obstacle in the own lane, the driver's uncomfortable feeling can be reduced.
(8) (b) If it is determined that the vehicle has left the adjacent lane in the right or left direction of the detectable area, the driver tends to feel a small risk potential RP with respect to the obstacle. The speed is gradually decreased at a quick speed (second speed) ΔFA2. Thereby, even when the obstacle is out of the target, it is possible to perform the reaction force control suited to the driver's feeling.
(9) (c) If it is determined that the driver has departed far away from the detectable area, the driver tends to feel a small risk potential RP with respect to the obstacle. Speed) Gradually decrease with ΔFA1. Thereby, even when the obstacle is out of the target, it is possible to perform the reaction force control suited to the driver's feeling.
(10) (d) If it is determined that the vehicle has left the detectable area in the own lane, for example, after a delay of a predetermined time T3 set as an estimated time until the obstacle leaves the own lane, The pedal reaction force FA is gradually reduced at a slow speed (fourth speed) ΔFA3. Since the time from when the obstacle is out of the target to when it is estimated that the obstacle has left the adjacent lane is set as the predetermined time T3, the start of the reduction of the pedal reaction force FA is not unnecessarily delayed and the driver Reaction force control that matches the sense of Further, even if the obstacle does not depart from the adjacent lane, the driver can judge the system state with a margin and perform an appropriate operation. Here, the reaction force control command value change rate ΔFA is set so as to satisfy ΔFA1 ≧ ΔFA2 ≧ ΔFA3 ≧ ΔFA4. Therefore, even when an obstacle is out of the target, the reaction force control suited to the driver's feeling is performed. be able to.
[0069]
In the above-described first embodiment, the predetermined time T4 is set to the predetermined value. However, the predetermined time T4 is set to a predetermined value in accordance with the magnitude of the pedal reaction force FA when the front obstacle is not detected. You can change it. For example, by shortening the delay time T4 as the pedal reaction force FA at the time of non-detection becomes smaller, the start timing of the decrease of the pedal reaction force is not unnecessarily delayed, and the timing matches the driver's feeling. Reaction force control can be performed.
[0070]
<< 2nd Embodiment >>
Next, a second embodiment of the present invention will be described. FIG. 12 is a system diagram showing a configuration of the vehicle driving assist system 2 according to the second embodiment, and FIG. 13 is a configuration diagram of a vehicle equipped with the vehicle driving assist system 2. In FIGS. 12 and 13, portions having the same functions as those in the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals. Here, differences from the first embodiment will be mainly described.
[0071]
In the second embodiment, the decrease pattern of the operation reaction force is changed according to the intention of the driver of the own vehicle when the front obstacle is out of the target.
[0072]
The lane recognition camera 40 is a small CCD camera, a CMOS camera, or the like attached to the upper part of the front window, detects the situation of the road ahead as an image, and outputs it to the controller 50A. The lane recognition camera 40 captures an image of a road surface several meters to several tens of meters ahead of the host vehicle, and detects a relative positional relationship between the host vehicle and a running lane marking (white line) based on the captured image. .
[0073]
Specifically, the lane recognition camera 40 performs image processing on the image captured by the CCD element to detect a white line on the road, and also extracts a plurality of parameters (hereinafter, road parameters) representing the road shape and the vehicle behavior. To detect. Furthermore, the lane recognition camera 40 updates the road parameters with time so that the white line model that mathematically represents the shape of the white line using the road parameters matches the white line detection result. It has the function of detecting the white line and estimating the road shape and vehicle behavior. Here, the road parameters include the lateral displacement yc of the center of gravity of the vehicle with respect to the lane center line (the center of the lane), the yaw angle φr of the vehicle with respect to the lane center line, the pitch angle η of the vehicle, and the road surface of the lane recognition camera 40. , The road curvature (the reciprocal of the radius of curvature) ρ, the lane width 2D, and the like.
[0074]
Further, the lane recognition camera 40 determines whether the white line is a solid line or a broken line based on the detected number of boundary points between the white line and the road surface, the continuity of the boundary point between the white line and the road surface, and the like. Based on the result, it is determined whether the lane in which the vehicle is currently traveling is a traveling lane or an overtaking lane. The lane recognition camera 40 outputs to the controller 50A a traveling lane determination signal that determines the type of lane in which the host vehicle is traveling, and estimated road parameters.
[0075]
FIG. 14 is a block diagram showing the internal configuration of the controller 50A. The controller 50A includes an obstacle recognition unit 51A, a risk potential calculation unit 52A, a driving operation reaction force determination unit 53A, a detectable area calculation unit 54A, an obstacle state estimation unit 55A, and a driving operation reaction force correction unit according to the software form of the CPU. 56A, a travel position recognition unit 57A, and a driver intention estimation unit 58A. The processes in the obstacle recognition unit 51A, the risk potential calculation unit 52A, the driving operation reaction force determination unit 53A, the detectable area calculation unit 54A, and the obstacle state estimation unit 55A are the same as those in the above-described first embodiment. is there.
[0076]
The traveling position recognition unit 57A calculates a lateral displacement from the center of the traveling lane where the host vehicle is predicted to arrive after a predetermined time, based on the road parameters and the traveling lane determination signal input from the lane recognition camera 40, Estimate how the vehicle is moving in the lane.
[0077]
The driver intention estimating unit 58A includes a moving state of the obstacle estimated by the obstacle state estimating unit 55A, a moving state of the own vehicle calculated by the traveling position recognizing unit 57A, and a traveling lane input from the lane recognition camera 40. The intention of the driver is estimated based on the judgment signal. Specifically, whether the cause of the laser radar 10 not detecting the forward obstacle (lost) or the moving of the forward obstacle out of the detection area of the laser radar 10 is due to the intention of the driver of the own vehicle. Then, it is estimated whether or not it is due to the behavior of the preceding vehicle which is an obstacle in front, and thereby the intention of the driver is estimated.
[0078]
The driving operation reaction force correction unit 56A excludes obstacles based on the movement of the obstacle estimated by the obstacle state estimation unit 55A and the driver's intention estimated by the driver intention estimation unit 58A. The reaction force control amount calculated by the driving operation reaction force determination unit 53A is corrected according to the state at the time of the occurrence.
[0079]
Next, the operation of the vehicle driving assist system 2 according to the second embodiment will be described with reference to FIG. FIG. 15 is a flowchart illustrating a processing procedure of a driving assist control process in a controller 50A according to the second embodiment. This processing is continuously performed at regular intervals, for example, every 50 msec.
[0080]
First, the running state is read in step S1100. Here, the traveling state is information on the traveling state of the own vehicle including the obstacle state ahead of the own vehicle. Therefore, the detection signals from the laser radar 10, the vehicle speed sensor 20, and the steering angle sensor 30 are read. Further, it reads the lateral displacement yc of the vehicle with respect to the lane center line, the yaw angle φr with respect to the lane center line, the road curvature (the reciprocal of the radius of curvature R) ρ, and the traveling lane judgment signal, which are detected by the lane recognition camera 40.
[0081]
In step S1200, as in step S200 of FIG. 4 in the first embodiment, the state of the obstacle ahead is recognized based on the running state data read and recognized in step S1100. Here, the relative position of the current obstacle with respect to the own vehicle, the moving direction and the moving speed thereof are recognized, and how the obstacle is arranged in front of the own vehicle with respect to the running of the own vehicle, Recognize how you are moving.
[0082]
In step S1250, the travel position of the own vehicle after a predetermined time is calculated from the road parameters and the travel lane determination signal read in step S1100. Specifically, based on the lateral displacement yc, the yaw angle φr, the road curvature ρ, and the like of the host vehicle, the lateral displacement ys from the center of the lane, which is predicted to reach the host vehicle after a predetermined time, is calculated. Note that the lateral displacement ys after a predetermined time is the lateral displacement from the center of the lane in which the vehicle is currently traveling, or, if the vehicle is changing lanes, from the center of the lane before the lane change. Lateral displacement. The lateral displacement ys of the vehicle after the predetermined time T uses the own vehicle speed V, the yaw angle φr of the own vehicle, and the current lateral displacement yc of the own vehicle, assuming that the direction of the vehicle body is in the traveling direction of the vehicle. Thus, it is obtained by the following (Equation 42).
(Equation 42)
ys = yc + V · T · φr (Equation 42)
[0083]
As shown in (Equation 42), the lateral displacement ys after the predetermined time is a lateral displacement from the center of the lane at a distance L = VT that the vehicle has traveled at the speed V for the predetermined time T. Therefore, this lateral displacement ys is defined as a forward fixation point lateral displacement. Further, the distance L is defined as a forward fixation point distance.
[0084]
The forward fixation point lateral displacement ys can also be calculated by the following (Equation 43) using the differential value dyc / dt of the current lateral displacement yc.
[Equation 43]
ys = yc + Tdyc / dt (Equation 43)
[0085]
In addition, when the vehicle is traveling on a curved road, the forward fixation point lateral displacement ys can be calculated using (Equation 44) so as to correct the deviation of the predicted value of the lateral displacement.
[Equation 44]
ys = yc + V · T · φr− (V · T) ^Two / 2 · ρ (Equation 44)
[0086]
In step S1300, a risk potential RP for an obstacle is calculated, and in step S1400, a reaction force control command value FA corresponding to the calculated risk potential RP is calculated. These processes are the same as the processes in steps S300 and S400 in the flowchart of FIG.
[0087]
In step S1500, a detectable area in the own lane is calculated from a forward area scanned by the laser radar 10 (for example, ± 6 [deg] with respect to the front of the own vehicle). FIG. 16 shows a detectable area when the own vehicle is traveling on a straight road, and FIG. 17 shows a detectable area when the own vehicle is traveling on a curved road. The detectable area in the own lane can be calculated in the same manner as the processing in step S500 of the flowchart of FIG. 4 described above. However, when the own vehicle is traveling on a curved road, for example, It can also be calculated.
[0088]
As shown in FIGS. 16 and 17, a coordinate system is set in which the center position in front of the host vehicle is the origin, the y-axis is the vehicle longitudinal direction, and the x-axis is the vehicle lateral direction. The forward direction of the vehicle is the + y direction, and the right direction of the vehicle is the + x direction. The scanning width of the laser radar is 2θ, the longest detection distance of the laser radar 10 is ymax, and the lane width is 2D.
[0089]
《Curved road》
The boundary of the radar scan range is represented by (Equation 45).
[Equation 45]
x = ± y · tanθ (Equation 45)
[0090]
・ In the case of a right curve with a radius of curvature | R | (see FIG. 17)
From a simple geometrical relationship, the left and right boundaries of the traveling lane are expressed by the following (Equation 46) and (Equation 47) using the radius of curvature R calculated by (Equation 11).
[Equation 46]
Traveling lane left boundary x = | R | -√ ｛(| R | + D) ^Two -Y ^Two ｝ (Equation 46)
[Equation 47]
Travel lane right boundary x = | R | -√ ｛(| R | -D) ^Two -Y ^Two ｝ (Equation 47)
Where y ≦ | R | −D
[0091]
As shown in FIG. 17, the area sandwiched between the radar scan range and the left and right boundaries of the traveling lane is the detectable area. In the case of a right curve with a radius of curvature | R | ).
[Equation 48]
−y · tanθ ≦ x ≦ y ・ tanθ and
| R | -√ ｛(| R | + D) ^Two -Y ^Two ｝ ≦ x ≦ | R | -√ ｛(| R | -D) ^Two -Y ^Two ｝ (Equation 48)
Where 0 <y ≦ ymax ≦ | R | −D
[0092]
・ In the case of a left curve with a radius of curvature | R |
The left and right boundaries of the traveling lane are represented by the following (Equation 49) and (Equation 50).
[Equation 49]
Traveling lane left boundary x =-| R | + √ ｛(| R | -D) ^Two -Y ^Two ｝ (Equation 49)
[Equation 50]
Traffic lane right boundary x =-| R | + √ ｛(| R | + D) ^Two -Y ^Two ｝ (Equation 50)
Where y ≦ | R | −D
[0093]
Thus, in the case of a left curve having a radius of curvature | R |, the detectable area is represented by the following (Equation 51).
(Equation 51)
−y · tanθ ≦ x ≦ y ・ tanθ and
− | R | + √ ｛(| R | −D) ^Two -Y ^Two ｝ ≦ x ≦ − | R | + √ ｛(| R | + D) ^Two -Y ^Two ｝ (Equation 51)
Where 0 <y ≦ ymax ≦ | R | −D
[0094]
Here, the traveling direction is estimated by obtaining the turning radius of the own vehicle from the vehicle speed and the steering angle. However, the present invention is not limited to this. For example, the traveling direction of the own vehicle is detected using a yaw rate sensor or a lateral acceleration sensor. You can also. Further, a camera image obtained by photographing a scene in front may be subjected to image processing to recognize a white line, or a road shape may be estimated based on road information obtained from a navigation system.
After calculating the detectable area of the laser radar 10 in step S1500, the process proceeds to step S1600.
[0095]
In step S1600, based on the relative position of the current obstacle recognized in step S1200 with respect to the own vehicle, the moving direction and the moving speed thereof, and the detectable area in the own lane calculated in step S1500, the obstacle is located within the own lane. Estimate how to move the detectable area. The processing performed in step S1600 will be described with reference to the flowchart in FIG.
[0096]
In step S1601, it is determined whether the laser radar 10 has detected an obstacle ahead. If an affirmative determination is made in step S1601, the process proceeds to step S1602. In step S1602, it is determined whether the forward obstacle is moving far away. If an affirmative determination is made in step S1602, the flow advances to step S1603 to set 10 to the obstacle state flag flgSTATE. If a negative determination is made in step S1602, the process advances to step S1604.
[0097]
In step S1604, it is determined whether the forward obstacle is moving to the right adjacent lane. If an affirmative determination is made in step S1604, the process advances to step S1605 to set 20 to the obstacle state flag flgSTATE. If a negative determination is made in step S1604, the process advances to step S1606.
[0098]
In step S1606, it is determined whether or not the front obstacle is moving to the left adjacent lane. If an affirmative determination is made in step S1606, the process advances to step S1607 to set 30 to the obstacle state flag flgSTATE. If a negative determination is made in step S1606, the process proceeds to step S1608.
[0099]
In step S1608, it is determined whether or not the front obstacle is moving outside the detectable area in the own lane. If an affirmative determination is made in step S1608, the process advances to step S1609 to set 40 to the obstacle state flag flgSTATE. If a negative determination is made in step S1608, the process advances to step S1610 to set 50 to the obstacle state flag flgSTATE.
[0100]
If it is determined in step S1601 that a forward obstacle has not been detected, the process advances to step S1611. In step S1611, it is determined whether the accelerator pedal reaction force control command correction value FAout calculated in the previous cycle is 0 or not. If an affirmative determination is made in step S1611, the flow advances to step S1612 to clear the obstacle state flag flgSTATE to 0. On the other hand, when the negative determination is made in step S1611 and the reaction force command correction value FAout is not 0, the obstacle state flag flgSTATE set in the previous cycle is used as it is.
[0101]
The determination as to whether or not the preceding obstacle is moving in the distant, adjacent lane, or outside the detectable area in the own lane in step S1602, step S1604, step S1606, and step S1608 is performed for a predetermined time T0 (eg, T0 = 1 [sec]) based on the position of the obstacle. This determination can be made in the same manner as in the first embodiment described above, but can also be made as follows. These determination methods will be described with reference to FIGS. 16 and 17 for each road shape. Here, the position of the forward obstacle is (x (0), y (0)), and the relative speed is (dx, dy).
[0102]
《On a straight road》
First, a method of determining in which direction the obstacle is moving in the case of a straight road will be described with reference to FIG.
The position (x (T0), y (T0)) of the obstacle ahead after the predetermined time T0 is expressed as (Equation 52).
(Equation 52)

It is.
[0103]
(H) Moving far away (flgSTATE = 10)
A sufficiently large T0 that satisfies −y · tan θ ≦ x (0) ≦ y · tan θ and −y · tan θ ≦ x (T0) ≦ y · tan θ is repeatedly calculated. When Expression 53) is satisfied, it can be determined that the forward obstacle is moving far away.
(Equation 53)
y (T0) ≧ ymax (Equation 53)
[0104]
(I) Moving to the adjacent lane on the right (flgSTATE = 20)
−D ≦ x (0) ≦ D ≦ x (T0) and a sufficiently small T0 that satisfies 0 <y (0) and y (T0) ≦ ymax is repeatedly calculated. When (Equation 54) is satisfied, it can be determined that the front obstacle is moving rightward.
(Equation 54)
−y · tan θ ≦ x (T0) ≦ y · tan θ (Equation 54)
[0105]
(J) Moving to the adjacent lane on the left (flgSTATE = 30)
A sufficiently small T0 that satisfies x (T0) ≦ −D ≦ x (0) ≦ D and 0 <y (0), y (T0) ≦ ymax is repeatedly calculated. When (Equation 55) is satisfied, it can be determined that the front obstacle is moving to the left.
[Equation 55]
−y · tan θ ≦ x (T0) ≦ y · tan θ (Equation 55)
[0106]
(K) Moving out of detectable area in own lane (flgSTATE = 40)
−y · tanθ ≦ x (T0) ≦ y · tanθ A sufficiently small T0 is repeatedly calculated, and if the running state of the forward obstacle satisfies the following (Equation 56), the forward obstacle can be detected in the own lane. It can be determined that the user is moving outside.
[Equation 56]
−D ≦ x (T0) ≦ D (Equation 56)
[0107]
《Curved road》
Next, a method of determining in which direction the obstacle is moving in the case of a curved road will be described with reference to FIG. Here, a right curve will be described as an example.
(L) Moving to a distant place (flgSTATE = 10)
A sufficiently large T0 that satisfies −y · tan θ ≦ x (0) ≦ y · tan θ and −y · tan θ ≦ x (T0) ≦ y · tan θ is repeatedly calculated. If Expression 57) is satisfied, it can be determined that the forward obstacle is moving far away.
[Equation 57]
y (T0) ≧ ymax (Equation 57)
[0108]
(M) Moving to adjacent lane
・ Move to the adjacent lane on the right (flgSTATE = 20)
| R | -√ ｛(| R | + D) ^Two -Y ^Two ｝ ≦ x (0) ≦ | R | −√ ｛(| R | −D) ^Two -Y ^Two A sufficiently small T0 that satisfies｝ ≦ x (T0) and 0 <y (0), y (T0) ≦ ymax is repeatedly calculated, and when the traveling state of the forward obstacle satisfies the following (formula 58), It can be determined that the forward obstacle is moving rightward.
[Equation 58]
−y · tan θ ≦ x (T0) ≦ y · tan θ (Equation 58)
[0109]
・ Move to the adjacent lane on the left (flgSTATE = 30)
x (T0) ≦ | R | −√ ｛(| R | + D) ^Two -Y ^Two ｝ ≦ x (0) ≦ | R | −√ ｛(| R | −D) ^Two -Y ^Two 十分, and a sufficiently small T0 that satisfies 0 <y (0), y (T0) ≦ ymax is repeatedly obtained. It can be determined that the vehicle is moving to the lane.
[Equation 59]
−y · tan θ ≦ x (T0) ≦ y · tan θ (Equation 59)
[0110]
(N) Moving out of detectable area in own lane (flgSTATE = 40)
−y · tan θ ≦ x (T0) ≦ y · tan θ A sufficiently small T0 is repeatedly calculated, and if the traveling state of the forward obstacle satisfies the following (Equation 60), the forward obstacle can be detected in the own lane. It can be determined that the user is moving outside.
[Equation 60]
| R | -√ ｛(| R | + D) ^Two -Y ^Two ｝ ≦ x (T0) ≦ | R | −√ ｛(| R | −D) ^Two -Y ^Two ｝ (Equation 60)
In the case of the left curve, the obstacle state can be calculated in the same manner.
After estimating the obstacle state in step S1600, the process proceeds to step S1650.
[0111]
In step S1650, a driver intention determination process is performed based on the road parameters read in step S1100 and the obstacle state estimated in step S1600. How to estimate the driver's intention will be described in detail with reference to the flowchart in FIG.
[0112]
In step S1651, based on the traveling lane determination signal input from the lane recognition camera 40, it is determined whether or not the own vehicle is currently traveling in the traveling lane among the overtaking lane and the traveling lane. If an affirmative determination is made in step S1651, the process proceeds to step S1652.
[0113]
In step S1652, it is determined whether the own vehicle is changing lanes from the traveling lane to the overtaking lane. The method for determining whether or not the lane change is being performed here will be described later. If a negative determination is made in step S1652, and the host vehicle is traveling in the traveling lane without changing lanes, the process proceeds to step S1660. In step S1660, a driver intention determination process A1 (described later with reference to FIG. 21) is performed to estimate a driving operation intention of the driver of the own vehicle. If the determination in step S1652 is affirmative, and the own vehicle is moving from the traveling lane to the overtaking lane, the process proceeds to step S1670 to perform driver intention determination processing A2 (described later using FIG. 22).
[0114]
On the other hand, if step S1651 is negatively determined and the vehicle is not traveling in the traveling lane, the process proceeds to step S1655. In step S1655, it is determined whether or not the own vehicle is changing lanes from an overtaking lane to a traveling lane. If a negative determination is made in step S1655, and the vehicle is traveling in the passing lane without changing lanes, the process proceeds to step S1680. In step S1680, driver intention determination processing B1 (described later with reference to FIG. 23) is performed. If the result of the determination in step S1655 is affirmative, and the own vehicle is moving from the overtaking lane to the traveling lane, the process proceeds to step S1690 to perform a driver intention determination process B2 (described later using FIG. 24).
[0115]
Here, the details of the lane change determination process of the own vehicle in step S1652 and step S1655 will be described with reference to FIGS. 20 (a) to (d) show how the host vehicle changes lanes from the traveling lane to the overtaking lane in the order of time.
[0116]
FIGS. 20A and 20B show a state in which the host vehicle is traveling in the traveling lane. In FIG. 20A, the host vehicle is traveling straight in the traveling lane. The lateral displacement yc of the host vehicle at this time is yc <D−W using the lane width 2D and the host vehicle width 2W. Further, the lateral displacement after a predetermined time T calculated using the above (Equation 42), that is, the forward fixation point lateral displacement ys is ys <D−W. In FIG. 20B, the own vehicle is not traveling straight, but the yaw angle φr with respect to the own lane is still sufficiently small, and the lane has not been changed. At this time, the lateral displacement yc of the host vehicle is yc <DW. Further, the forward fixation point lateral displacement ys is ys <D.
[0117]
Therefore, when the current lateral displacement yc and the forward gazing point lateral displacement ys of the host vehicle satisfy the following (Equation 61), it is determined that the host vehicle is not changing lanes and is running in the driving lane.
[Equation 61]
ys <D and yc <D−W (Equation 61)
[0118]
As described above, in a state where the own vehicle does not cross the lane marking line (white line) and the forward gazing point lateral displacement ys exists in the traveling lane, the own vehicle is still in the lane change operation. You can determine that there is no. Therefore, when the traveling state of the host vehicle satisfies (Equation 61), a negative determination is made in step S1652.
[0119]
FIG. 20C shows a situation in which the host vehicle is crossing a white line while the host vehicle is changing lanes from a traveling lane to a passing lane. When the current lateral displacement yc and the forward gazing point lateral displacement ys of the own vehicle satisfy the following (Equation 62), it is determined that the own vehicle is changing lanes from the traveling lane to the overtaking lane.
(Equation 62)
D−W ≦ yc ≦ D + W and ys ≧ D (Equation 62)
[0120]
FIG. 20D illustrates a state where the own vehicle has completed the lane change to the overtaking lane. When the current lateral displacement yc and the forward gazing point lateral displacement ys of the own vehicle satisfy the following (Equation 63), it is determined that the lane change from the traveling lane to the overtaking lane has been completed.
[Equation 63]
yc> D + W and ys> D + W (Equation 63)
[0121]
Therefore, when the current lateral displacement yc and the forward gazing point lateral displacement ys of the own vehicle satisfy the following (Equation 64), it is determined that the own vehicle is changing lanes from the traveling lane to the overtaking lane, and the result in step S1652 is affirmative. Is determined.
[Equation 64]
yc ≧ D−W and ys ≧ D (Equation 64)
Note that the lane change from the overtaking lane to the traveling lane can be similarly determined.
[0122]
Next, the driver intention determination processing in steps S1660, S1670, S1680 and S1690 will be described. Here, the driver's intention is determined in accordance with the state of the obstacle ahead determined in step S1600 and the traveling state of the host vehicle determined in steps S1652 and S1655. First, the driver intention determination processing A1 in step S1660 will be described with reference to FIG. Note that the process A1 is a process in a case where the own vehicle keeps traveling in the traveling lane.
[0123]
In step S1661, it is determined whether or not the obstacle state flag flgSTATE = 10 set in step S1600. When step S1661 is determined to be affirmative, for example, as shown in FIG. 25, the preceding vehicle is moving further forward while the own vehicle keeps traveling in the traveling lane. Therefore, the process proceeds to step S1662, and the intention determination flag flgAIM indicating the intention of the driver is set to 0 (cruise). If a negative determination is made in step S1661, the process proceeds to step S1663.
[0124]
In the step S1663, it is determined whether or not the obstacle state flag flgSTATE = 20. When the determination in step S1663 is affirmative, for example, as shown in FIG. 26, it is a state in which the preceding vehicle has changed lanes to the overtaking lane while the own vehicle keeps traveling in the traveling lane. Therefore, the process proceeds to step S1664, and the intention determination flag flgAIM is set to 0 (cruise). If a negative determination is made in step S1663, the process proceeds to step S1665.
[0125]
In step S1665, it is determined whether or not the obstacle state flag flgSTATE = 30. When step S1665 is determined to be affirmative, for example, as shown in FIG. 27, the preceding vehicle enters the left branch while the own vehicle keeps traveling in the traveling lane. Therefore, the process proceeds to step S1666, and the intention determination flag flgAIM is set to 0 (cruise). If a negative determination is made in step S1665, the process proceeds to step S1667.
[0126]
In the processing after step S1667, the intention determination flag flgAIM is set to 0 (cruise) regardless of the value of the obstacle determination flag flgSTATE.
[0127]
As described above, when the own vehicle is traveling in the traveling lane without changing lanes, the driver maintains traveling in the traveling lane, presumes that the driver intends to travel in a steady manner, and recognizes that the driver Regardless of the state, the intention determination flag flgAIM is set to 0.
[0128]
Next, the driver intention determination processing A2 in step S1670 will be described with reference to FIG. Note that the process A2 is a process when the own vehicle is changing lanes from the traveling lane to the overtaking lane.
In step S1671, it is determined whether or not the obstacle determination flag flgSTATE = 10, that is, whether or not the front obstacle is moving far. If the determination in step S1671 is affirmative, it is estimated that the driver intends to reach the preceding vehicle as the driver intends to go ahead because the obstacle ahead is moving away at the same time as the driver changes lanes to the passing lane. Therefore, the process proceeds to step S1672, and the intention determination flag flagAIM is set to 20 (following). If a negative determination is made in step S1671, the process proceeds to step S1673.
[0129]
In step S1673, it is determined whether or not the obstacle determination flag flgSTATE = 20, that is, whether or not the preceding obstacle is moving to the right lane. If an affirmative determination is made in step S1673, the preceding obstacle moves further rightward while the own vehicle is moving to the overtaking lane, and is not detected. This may be due to the case where the preceding vehicle has made a right branch or an erroneous detection of the laser radar 10. Therefore, it is estimated that the driver intends to maintain the current state, and the process proceeds to step S1674 to set 0 (cruise) in the intention determination flag flagAIM. If a negative determination is made in step S1673, the flow shifts to step S1675.
[0130]
In step S1675, it is determined whether or not the obstacle determination flag flgSTATE = 30, that is, whether or not the front obstacle is moving to the left lane. When step S1675 is affirmatively determined, for example, as shown in FIG. 28, it is considered that the preceding vehicle is maintaining the traveling lane and only the own vehicle is moving to the overtaking lane. Therefore, it is estimated that the driver has an intention to pass, and the flow shifts to step S1676 to set 1 (overtaking) in the intention determination flag flagAIM. If a negative determination is made in step S1675, the flow advances to step S1677.
[0131]
In the processing after step S1677, the intention determination flag flgAIM is set to 0 (cruise) regardless of the value of the obstacle determination flag flgSTATE.
[0132]
Next, the driver intention determination processing B1 in step S1680 will be described with reference to FIG. Note that the process B1 is a process in a case where the own vehicle keeps running in the overtaking lane.
[0133]
In step S1681, it is determined whether or not the obstacle determination flag flgSTATE = 10, that is, whether or not the forward obstacle is moving far. When step S1681 is affirmatively determined, for example, as shown in FIG. 29, the vehicle traveling ahead of the own vehicle is in a situation of moving further forward, but the driver tries to maintain the overtaking lane. It is in the state of being. Therefore, it is estimated that the driver intends to arrive at the preceding vehicle as the driver's intention, and the flow shifts to step S1682 to set 2 (follow-up) in the intention determination flag flagAIM. If a negative determination is made in step S1681, the process moves to step S1683.
[0134]
In step S1683, it is determined whether or not the obstacle determination flag flgSTATE = 20, that is, whether or not the front obstacle is moving rightward. If an affirmative determination is made in step S1683, the obstacle in front of the host vehicle is moving further to the right while traveling in the passing lane, and is not detected. This may be due to the preceding vehicle entering the right branch, erroneous detection of the laser radar 10, or the like. Therefore, it is estimated that the driver's intention is to maintain the current state, and the flow shifts to step S1684 to set the intention determination flag flagAIM to 0 (cruise). If a negative determination is made in step S1683, the process proceeds to step S1685.
[0135]
In step S1685, it is determined whether or not the obstacle determination flag flgSTATE = 30, that is, whether or not the front obstacle is moving leftward. When step S1685 is affirmatively determined, for example, as shown in FIG. 30, the preceding vehicle is moving from the overtaking lane to the traveling lane. Since the own vehicle keeps traveling in the overtaking lane, it is estimated that the driver intends to overtake, and the flow shifts to step S1686 to set the intention determination flag flagAIM to 1 (overtaking). If a negative determination is made in step S1685, the process proceeds to step S1687.
[0136]
In the processing after step S1687, the intention determination flag flgAIM is set to 0 (cruise) regardless of the value of the obstacle determination flag flgSTATE.
[0137]
Next, the driver intention determination processing B2 in step S1690 will be described with reference to FIG. The process B2 is a process in a case where the own vehicle is changing lanes from an overtaking lane to a traveling lane.
[0138]
In step S1691, it is determined whether or not the obstacle determination flag flgSTATE = 10, that is, whether or not the front obstacle is moving far. When step S1691 is affirmatively determined, the vehicle traveling ahead of the host vehicle is moving further forward, but the driver stops overtaking and is returning to the traveling lane. . Therefore, it is determined that the driver's intention is to maintain the current state, and the flow shifts to step S1692 to set the intention determination flag flagAIM to 0 (cruise). If a negative determination is made in step S1691, the process moves to step S1693.
[0139]
In step S1693, it is determined whether or not the obstacle determination flag flgSTATE = 20, that is, whether or not the front obstacle is moving rightward. If the determination in step S1693 is affirmative, for example, as shown in FIG. 31, it is estimated that the own vehicle is about to pass a vehicle traveling in the overtaking lane from the traveling lane. Therefore, in order to inform the driver of the current driving situation and to suppress positive acceleration, the flow shifts to step S1694 to set 3 (non-acceleration) in the intention determination flag flagAIM. If a negative determination is made in step S1693, the process proceeds to step S1695.
[0140]
In the processing after step S1695, the intention determination flag flgAIM is set to 0 (cruise) regardless of the value of the obstacle determination flag flgSTATE.
After performing the driver intention determination processing in step S1650 as described above, the process proceeds to step S1700.
[0141]
In step S1700, based on the movement of the obstacle estimated in step S1600 and the driver's intention estimated in step S1650, the reaction force control calculated in step S1400 according to the state when the obstacle is excluded from the target. The command value FA is corrected, and a reaction force command correction value FAout is calculated. The process of calculating the reaction force command correction value FAout in step S1700 will be described with reference to the flowchart in FIG.
[0142]
In step S1701, the obstacle exists in the detectable area in the own lane based on the position (x (0), y (0)) of the forward obstacle detected by the laser radar 10 and the detectable area in the own lane. It is determined whether or not to perform. If an affirmative determination is made in step S1701, the process proceeds to step S1702. In step S1702, a lost elapsed time counter Cnt_lost indicating the elapsed time from the time when the forward obstacle is no longer detected (lost) is cleared to zero. Further, the reaction force control command value FA calculated in step S1400 is set as a reaction force command correction value FAout.
[0143]
If a negative determination is made in step S1701, the process advances to step S1703 to determine whether the obstacle state flag flgSTATE is 10, 20, or 30. If the result of the determination in step S1703 is affirmative, and the obstacle in front is out of the target range because it has moved to the distant, right or left lane, the process proceeds to step S1720. In step S1720, a driving operation reaction force correction process A is performed as shown in the flowchart of FIG.
[0144]
In the driving operation reaction force correction processing A in step S1720, first, in step S1721, it is determined whether the intention determination flag flgAIM is 1. If the determination in step S1721 is affirmative, and the driver's intention is to overtake, the process advances to step S1722. In step S1722, ΔFA5 (for example, 10 [kgf / s]) is set as the reaction force control command value change rate ΔFA. If a negative determination is made in step S1721, the process moves to step S1723.
[0145]
In step S1723, it is determined whether the intention determination flag flgAIM is 2. If the determination in step S1723 is affirmative, and the driver intends to reach the preceding vehicle, the process proceeds to step S1724. In step S1724, ΔFA6 (for example, 8 [kgf / s]) is set as the reaction force control command value change rate ΔFA. If a negative determination is made in step S1723, the process moves to step S1725.
[0146]
In step S1725, it is determined whether the intention determination flag flgAIM is 3. If the result of the determination in step S1725 is affirmative, and the own vehicle is in a situation where the vehicle traveling on the overtaking lane is overtaking the traveling lane, the process proceeds to step S1726. In step S1726, ΔFA7 (for example, 4 [kgf / s]) is set to the reaction force control command value change rate ΔFA in order to notify the driver of the current driving situation and suppress positive acceleration. If a negative determination is made in step S1725, the flow shifts to step S1727 to set ΔFA8 (for example, 8 [kgf / s]) as the reaction force control command value change rate ΔFA.
[0147]
The reaction force control command value change rates ΔFA5 to ΔFA8 set in steps S1722, S1724, S1726, and S1728 are set to appropriate values in advance so as to satisfy the relationship of ΔFA5 ≧ ΔFA6 ≧ ΔFA8 ≧ ΔFA7.
[0148]
On the other hand, in the flowchart of FIG. 32, a negative determination is made in step S1703, and the forward obstacle moves outside the detectable area in the own lane and is not detected, or the forward obstacle is not detected due to a gradient of a road or the like. Or, if there is no obstacle ahead, the process proceeds to step S1740. In step S1740, the driving operation reaction force correction processing B is performed as shown in the flowchart of FIG.
[0149]
In the driving operation reaction force correction processing B in step S1740, first, in step S1741, it is determined whether or not the obstacle state flag flgSTATE is 40. If an affirmative determination is made in step S1741, and the obstacle ahead moves outside the detectable area in the own lane, the flow shifts to step S1742. In step S1742, it is determined whether the lost elapsed time counter Cnt_lost is smaller than a predetermined time T3 (for example, 1 [sec]). Here, the predetermined time T3 is the same as the value used in the driving operation reaction force correction processing (S708 in FIG. 11) of the above-described first embodiment.
[0150]
If an affirmative determination is made in step S1742, the process proceeds to step S1743, in which the reaction force control command value change rate ΔFA is set to 0 so that the reaction force reduction start timing is delayed by a predetermined time T3. If a negative determination is made in step S1742, it is estimated that the obstacle outside the detectable area in the own lane has completely moved to the adjacent lane, and the flow proceeds to step S1744. In step S1744, ΔFA3 (for example, 5 [kgf / s]) is set to the reaction force control command value change rate ΔFA.
[0151]
If a negative determination is made in step S1741, the process proceeds to step S1745. In step S1745, it is determined whether the lost elapsed time counter Cnt_lost is smaller than a predetermined time T4 (for example, 2 [sec]). If an affirmative determination is made in step S1745, the process proceeds to step S1746, in which the reaction force control command value change rate ΔFA is set to 0 so that the reaction force reduction start timing is delayed by a predetermined time T4. If a negative determination is made in step S1745, the process advances to step S1747 to set ΔFA4 (for example, 3 [kgf / s]) as the reaction force control command value change rate ΔFA. The reaction force control command values ΔFA3 and ΔFA4 are the same as the values used in the driving operation reaction force correction processing (S710 and S713 in FIG. 11) of the above-described first embodiment. Here, ΔFA5 ≧ ΔFA6 ≧ ΔFA3 ≧ ΔFA4.
[0152]
In the driving operation reaction force correction processing A in step S1720 or the driving operation reaction force correction processing B in step S1740, the process proceeds to step S1704 after setting the reaction force control command value change rate ΔFA.
[0153]
In step S1704, it is determined whether the previously set reaction force command correction value FAout is greater than the reaction force control command value change rate ΔFA set in step S1720 or S1740. If an affirmative determination is made in step S1704, the process advances to step S1705 to increment the lost elapsed time counter Cnt_lost by one. Further, a value obtained by subtracting the reaction force control command value change rate ΔFA from the previous reaction force command correction value FAout is set as a new reaction force command correction value FAout. If a negative determination is made in step S1704, the process advances to step S1706. In step S1706, the reaction force command correction value FAout is set to zero.
After calculating the reaction force command correction value FAout in step S1700 as described above, the process proceeds to step S1800.
[0154]
In step S1800, the reaction force command correction value FAout calculated in step S1700 is output to accelerator pedal reaction force control device 60, and the current process ends.
[0155]
FIG. 35 schematically shows a change in the operation reaction force FA according to the driver's intention. The horizontal axis in FIG. 35 indicates time t, and it is assumed that at time tl, the forward obstacle has departed from the own lane or the detectable area and has been excluded from the reaction force control.
[0156]
When the driver intends to overtake (flgAIM = 1), the operation reaction force FA is rapidly reduced at the reaction force control command value change rate ΔFA5 so that the overtaking operation can be easily performed. If the driver intends to follow (flgAIM = 2) or cruise (flgAIM = 0), the reaction force control is performed so that the operation reaction force FA does not suddenly change at the time t1 when the obstacle in front is out of the target. The operation reaction force FA is gradually reduced at the command value change rates ΔFA6 and ΔFA8. When the driver's intention is non-acceleration (flgAIM = 3), the operation reaction force FA is slowly reduced at the reaction force control command value change rate ΔFA7 to suppress the driver's acceleration operation.
[0157]
As described above, in the second embodiment described above, the following operational effects can be obtained.
(1) When the obstacle is out of scope, the change pattern of the pedal reaction force is corrected in consideration of the driver's intention estimated by the driver intention estimation unit 58A. Thereby, when the front vehicle stops existing in a state where the pedal reaction force FA is increasing in accordance with the inter-vehicle distance with the preceding vehicle, the change in the pedal reaction force is effectively corrected, and the driver's uncomfortable feeling is further improved. It can be further reduced.
(2) The driver intention estimating unit 58A estimates the driver's intention based on the road condition detected by the lane recognition camera 40 and the traveling position of the own vehicle detected by the traveling position recognition unit 57A. Intention can be accurately estimated.
(3) The driver intention estimating unit 58A estimates whether the own vehicle is traveling in a fixed lane or changing lanes. Based on the estimation result and a signal from the laser radar 10, an obstacle is estimated. Estimate the driver's intention when is excluded from the target. This makes it possible to more accurately estimate the driver's intention from the viewpoint of whether the obstacle is excluded from the target due to the behavior of the obstacle or the driver's intention.
(4) When the obstacle is not detected in the (a) detectable area, the operation reaction force correction unit 56A uses the fifth reduction pattern to move the obstacle out of the detectable area in the own lane. When the vehicle departs (flgSTATE = 40), the sixth decrease pattern indicates (b) when the vehicle departs to the right lane or left lane of the detectable area (flgSTATE = 20, 30), or (c) detectable When the vehicle has left the area (flgSTATE = 10), the accelerator pedal reaction force FA is reduced in a decreasing pattern according to the driver's intention. Accordingly, the pedal reaction force control that effectively reduces the driver's discomfort can be performed in consideration of the obstacle state and the driver's intention when the obstacle is out of the target. If it is detected that the forward obstacle has left the detectable area farther or in the left-right direction, it is considered that the risk potential for the obstacle is small. Therefore, by setting the decrease pattern of the pedal reaction force FA based on the driver's intention, it is possible to perform the reaction force control that meets the driver's intention.
(5) (a) If it is determined that the detection is not performed in the detectable area, the non-detection may occur due to a temporary performance drop or a gradient of the laser radar 10 despite the presence of an obstacle in front of the own lane. It may have been detected. Therefore, after a delay of a predetermined time T4, the pedal reaction force FA is gradually reduced at a slow speed (fifth speed) ΔFA4. (D) If it is determined that the vehicle has departed outside the detectable area in the own lane, for example, after a delay of a predetermined time T3 set as an estimated time until the obstacle departs out of the own lane, ΔFA4 At a high speed (sixth speed) ΔFA3, the pedal reaction force FA is gradually reduced. By providing the delay times T3 and T4, even when an obstacle becomes out of target, the driver can determine the state of the system with a margin and perform an appropriate operation. In addition, if the time when the obstacle is estimated to have left the lane is set to the predetermined time T3, the timing to start decreasing the pedal reaction force FA is not unnecessarily delayed, and matches the driver's feeling. Reaction force control can be performed.
(6) The driver intention estimating unit 58A determines whether the driver has left the obstacle in the (b) right lane or left lane of the detectable area, or (c) the driver has left the obstacle far away from the detectable area. Is intended to be any one of (A) cruising while maintaining the current running state, (B) overtaking obstacles, (C) following along obstacles, and (D) non-acceleration. When the driver's intention is (A) cruising, the operation reaction force correction unit 56A uses the seventh reduction pattern, (B) overtakes the vehicle using the eighth reduction pattern, (C) In this case, the accelerator pedal reaction force FA is reduced in the ninth decrease pattern, and (D) in the case of non-acceleration, in the tenth decrease pattern. Thus, effective pedal reaction force control can be performed according to the driver's intention estimated with high accuracy.
(7) If the driver's intention is (A) cruising, it is determined that the driver has no intention of overtaking or following and has an intention of maintaining the current traveling state. Therefore, the pedal reaction force FA is gradually reduced at ΔFA8 (seventh speed) so that the pedal reaction force is not suddenly decreased and stable cruising traveling is easily maintained. (B) In the case of overtaking, it is determined that the driver intends to actively accelerate. Therefore, the pedal reaction force FA is gradually reduced at a speed (eighth speed) ΔFA5 higher than ΔFA8 so that the pedal reaction force is quickly reduced and the operation of the driver is surely reflected in the vehicle behavior. (C) In the case of following, the pedal reaction force FA gradually decreases at a speed (a ninth speed) ΔFA6 higher than ΔFA8. (D) In the case of non-acceleration, it is determined that an unfavorable situation such as overtaking a vehicle traveling in the overtaking lane from the traveling lane side in a state where the own vehicle has moved from the overtaking lane to the traveling lane is determined. Then, in order to suppress the acceleration operation by the driver and suppress the overtaking action, the pedal reaction force FA is gradually reduced at a slow speed (tenth speed) ΔFA7. Here, since the reaction force control command value change rate ΔFA is set to satisfy ΔFA5 ≧ ΔFA6 ≧ ΔFA8 ≧ ΔFA7, it is possible to perform an effective reaction force control that meets the driver's intention. Further, by setting the reaction force control command value change rate ΔFA so as to satisfy ΔFA5 ≧ ΔFA6 ≧ ΔFA3 ≧ ΔFA4, it is possible to perform effective reaction force control that meets the driver's intention.
[0158]
In the above-described first and second embodiments, the reaction force control command value FA is reduced in a predetermined decrease pattern (reaction force control command value change rate ΔFA). , Can be reduced in a curved manner. Further, the decrease pattern (reaction force control command value change rate ΔFA) may be determined according to, for example, the time until the reaction force control command value FA becomes a predetermined value, for example, 0. In other words, the reaction force control command value change rate ΔFA is set such that the pedal reaction force FA becomes equal to or less than a predetermined value a predetermined time after the obstacle is excluded from the target. Assuming that the reaction force control command value FAd and the reaction force control command value FA when the obstacle is out of target become 0 after a predetermined time Td, the reaction force control command value change rate ΔFA is expressed by the following (Equation 64). Can be calculated.
[Equation 65]
ΔFA = FAd / Td (Equation 64)
[0159]
As described above, the decrease pattern when the operation reaction force is reduced is changed according to the magnitude of the pedal reaction force when the obstacle is excluded from the target. When the front vehicle stops being present in the state where the reaction force is increasing, the reaction force of the pedal can be promptly reduced, and the reaction force control suited to the driver's feeling can be performed. Since the reduction pattern is changed so that the pedal reaction force becomes a predetermined value or less after a predetermined time after the obstacle is excluded, regardless of the magnitude of the pedal reaction force when the obstacle is excluded from the target, The time required for the pedal reaction force to decrease to the predetermined value becomes equal, and the reaction force control more suited to the driver's feeling can be performed.
[0160]
In the above-described embodiment, the accelerator pedal reaction force control is performed according to the risk potential RP with respect to the forward obstacle. However, the invention is not limited thereto, and the brake pedal reaction force control may be performed. The method of calculating the risk potential RP is not limited to the above-described embodiment. For example, a function of an inter-vehicle time THW obtained by dividing the inter-vehicle distance by the own vehicle speed or the preceding vehicle speed, or a function of the time to contact TTC and the inter-vehicle time THW may be used. It is also possible to calculate the risk potential RP by combining with the function of The characteristic of the accelerator pedal reaction force control command value FA with respect to the risk potential RP is not limited to FIG.
[0161]
In the above-described embodiment, the method of calculating the detectable area and the method of determining the state of the obstacle by the laser radar 10 have been described using mathematical expressions. However, when the obstacle leaves the own lane or outside the detectable area, the target The method is not limited to the above-described method as long as the state when the vehicle goes outside can be accurately estimated.
[0162]
Furthermore, the obstacle state is estimated as one of departure to a distant place, departure to the right or left lane, and departure outside the detectable area in the own lane, and cruise, follow, overtake and Estimated as either non-accelerated. However, the present invention is not limited to this, and it is also possible to set other obstacle states and driver intentions, and to set a reduction pattern of the pedal reaction force according to them.
[0163]
In the above embodiment, the laser radar 10, the vehicle speed sensor 20, and the steering angle sensor 30 are used as obstacle detecting means, the accelerator pedal reaction force control device 60 is used as operation reaction force generating means, and the lane is used as road condition recognition means. A recognition camera 40 was used. However, the present invention is not limited to these. For example, instead of the laser radar 10, another type of millimeter wave radar or a CCD or CMOS camera can be used as the obstacle detecting means.
[Brief description of the drawings]
FIG. 1 is a system diagram of a vehicle driving assist system according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a vehicle equipped with the vehicle driving assist system shown in FIG.
FIG. 3 is a block diagram showing an internal configuration of a controller.
FIG. 4 is a flowchart illustrating a processing procedure of a driving assist control process in the controller according to the first embodiment;
FIG. 5 is a map showing characteristics of an accelerator control reaction force command value with respect to a longitudinal risk potential.
FIG. 6 is a diagram illustrating a method for calculating a detectable area on a straight road.
FIG. 7 is a diagram illustrating a method for calculating a detectable area on a curved road.
FIG. 8 is a flowchart showing a processing procedure of processing performed in the obstacle state estimation processing.
FIG. 9 is a diagram illustrating a method for estimating an obstacle state on a straight road.
FIG. 10 is a diagram illustrating a method for estimating an obstacle state on a curved road.
FIG. 11 is a flowchart showing a processing procedure of processing performed in the driving operation reaction force correction processing.
FIG. 12 is a system diagram showing a configuration of a vehicle driving assist system according to a second embodiment.
FIG. 13 is a configuration diagram of a vehicle equipped with the vehicle driving assist device shown in FIG. 1;
FIG. 14 is a block diagram showing an internal configuration of a controller.
FIG. 15 is a flowchart illustrating a processing procedure of a driving assist control process in the controller according to the second embodiment;
FIG. 16 is a diagram illustrating a method of calculating a detectable area on a straight road and a method of estimating an obstacle state.
FIG. 17 is a diagram illustrating a method for calculating a detectable area on a curved road and a method for estimating an obstacle state.
FIG. 18 is a flowchart illustrating a processing procedure of processing performed in the obstacle state estimation processing.
FIG. 19 is a flowchart illustrating a processing procedure of a process performed in a driver intention estimation process.
20A to 20D are diagrams for explaining a method of estimating a driver intention.
FIG. 21 is a flowchart showing a processing procedure in a driver intention determination processing A1.
FIG. 22 is a flowchart showing a processing procedure in driver intention determination processing A2.
FIG. 23 is a flowchart showing a processing procedure in driver intention determination processing B1.
FIG. 24 is a flowchart showing a processing procedure in a driver intention determination processing B2.
FIG. 25 is a diagram showing a traveling state when the driving intention is cruising.
FIG. 26 is a diagram showing a traveling state when the driving intention is cruising.
FIG. 27 is a diagram showing a traveling state when the driving intention is cruising.
FIG. 28 is a diagram showing a traveling state when the driving intention is overtaking.
FIG. 29 is a diagram showing a traveling state in a case where the driving intention is pursuit.
FIG. 30 is a diagram showing a traveling state in a case where the driving intention is overtaking.
FIG. 31 is a diagram showing a traveling state when the driving intention is non-acceleration.
FIG. 32 is a flowchart showing a processing procedure in driving operation reaction force correction processing.
FIG. 33 is a flowchart showing a processing procedure in driving operation reaction force correction processing A;
FIG. 34 is a flowchart showing a processing procedure in driving operation reaction force correction processing B;
FIG. 35 is a diagram schematically showing a change in an operation reaction force after an obstacle is excluded from a target.
[Explanation of symbols]
10: Laser radar
20: Vehicle speed sensor
30: steering angle sensor
40: Vehicle speed sensor
50, 50A: Controller
60: accelerator pedal reaction force control device
70: Servo motor

Claims (25)

Obstacle detection means for detecting an obstacle present around the own vehicle;
Risk potential calculation means for calculating a risk potential of the own vehicle with respect to the obstacle, based on a signal from the obstacle detection means,
Based on a signal from the risk potential calculation means, according to a preset change pattern, operation reaction force determination means for determining an operation reaction force to be generated in the vehicle operation device,
An operation reaction force generation unit that generates an operation reaction force on the vehicle operation device based on a signal from the operation reaction force determination unit,
An operation reaction assisting device for a vehicle, comprising: an operation reaction force correction unit that corrects the change pattern when an obstacle detected by the obstacle detection unit is excluded from the target. The vehicle driving assist system according to claim 1,
The operation reaction force correction unit is configured to delay the operation reaction force of the vehicle operating device for a predetermined time and then reduce the change when the obstacle detected by the obstacle detection unit is excluded from the target. A vehicle driving assist system for correcting a pattern. The vehicle driving assist system according to claim 1,
The operation reaction force correction unit corrects the change pattern so as to gradually reduce the operation reaction force of the vehicle operation device when the obstacle detected by the obstacle detection unit is excluded from the target. A driving assistance device for a vehicle, comprising: The vehicle driving assist device according to claim 2 or 3,
The operation reaction force correction unit reduces the operation reaction force according to the magnitude of the operation reaction force of the vehicle operation device when the obstacle detected by the obstacle detection unit is excluded from the target. A driving operation assisting device for a vehicle, characterized by changing a decrease pattern at the time. The vehicle driving assist device according to claim 4,
The vehicle driving assist system according to claim 1, wherein the operation reaction force correction means sets the change pattern such that the operation reaction force becomes a predetermined value or less after a predetermined time from when the obstacle is excluded from the target. apparatus. The vehicle driving assist system according to claim 1,
Obstacle recognizing means for recognizing a traveling state of the obstacle based on a signal from the obstacle detecting means,
Based on a signal from the obstacle recognition means, further comprising an obstacle state estimation means for estimating an obstacle state when the obstacle is excluded from the target,
The driving reaction assisting device for a vehicle, wherein the operation reaction force correcting unit corrects the change pattern based on a signal from the obstacle state estimating unit when the obstacle is out of target. . The vehicle driving assist system according to claim 6,
Further comprising a detectable area calculating means for calculating a detectable area in the own lane which can be detected by the obstacle detecting means,
The obstacle state estimating means is configured to detect the obstacle when the obstacle is excluded from the target based on the signal from the obstacle recognizing means and the detectable area calculated by the detectable area calculating means. A vehicle driving assist system for estimating a state. The vehicle driving assist system according to claim 7,
The obstacle state estimating means may detect the obstacle state when the obstacle is out of the target by (a) not detecting the object in the detectable area, and (b) the right lane of the detectable area. Or (c) departed far away from the detectable area, (d) departed out of the detectable area in the own lane,
The operation reaction force correction means reduces the operation reaction force of the vehicle device in a first decrease pattern when the obstacle is not detected in the detectable region (a). When the vehicle departs to the right lane or the left lane of the detectable region, the operation reaction force of the vehicle device is reduced in the second decrease pattern, and (c) when the vehicle departs far from the detectable region, the third (D) reducing the operation reaction force of the vehicle equipment in a fourth reduction pattern when the vehicle departs outside the detectable area in the own lane. Driving assist device for vehicles. The driving assistance device for a vehicle according to claim 8,
The first reduction pattern is characterized in that the operation reaction force is gradually reduced at a first speed after a delay of a predetermined time after the obstacle is excluded from the target, and the driving operation assistance device for a vehicle is characterized in that: . The vehicle driving assist system according to claim 9,
The vehicle, wherein the operation reaction force correction unit sets the predetermined time in the first decrease pattern in accordance with an operation reaction force of the vehicle operation device when the obstacle is out of target. Driving operation assist device. The driving assistance device for a vehicle according to claim 8,
The vehicle driving assist system according to claim 2, wherein the second reduction pattern gradually reduces the operation reaction force at a second speed higher than the speed according to the first reduction pattern. The driving assistance device for a vehicle according to claim 8,
The vehicle driving assist system according to claim 3, wherein the third reduction pattern gradually reduces the operation reaction force at a third speed higher than the speed according to the first reduction pattern. The driving assistance device for a vehicle according to claim 8,
The fourth reduction pattern is faster than the speed according to the first reduction pattern and is faster than the speed according to the second and third reduction patterns after a predetermined time delay after the obstacle is excluded from the target. A driving assist system for a vehicle, wherein the operation reaction force is gradually reduced at a fourth slow speed. The vehicle driving assist device according to claim 13,
The operation reaction force correction unit is configured to determine, based on a signal from the obstacle recognition unit, a time period from when the obstacle becomes out of target to when it is estimated that the obstacle has left the adjacent lane, in the fourth decrease pattern. The driving operation assisting device for a vehicle, characterized in that the predetermined time is set according to the following. The vehicle driving assist system according to claim 1,
Further comprising intention estimating means for estimating the intention of the driver driving the own vehicle,
The vehicle driving method, wherein the operation reaction force correction unit corrects the change pattern in accordance with a driver's intention estimated by the intention estimation unit when the obstacle becomes out of target. Operation assistance device. The vehicle driving assist device according to claim 15,
Road condition recognition means for recognizing the road condition ahead of the vehicle;
A traveling position recognition unit that detects a traveling position of the host vehicle based on a recognition state by the road state recognition unit;
The driving operation assisting device for a vehicle, wherein the intention estimating means estimates a driver's intention based on a signal from the traveling position recognizing means. The vehicle driving assist device according to claim 16,
The intention estimating means estimates whether the vehicle is traveling in a lane or changing lanes based on a signal from the traveling position recognizing means. A driving assist system for a vehicle, which estimates a driver's intention when the obstacle is out of the target based on a signal from a detecting unit. The driving assistance device for a vehicle according to claim 17,
Obstacle recognizing means for recognizing a traveling state of the obstacle based on a signal from the obstacle detecting means,
Detectable area calculating means for calculating a detectable area in the own lane which can be detected by the obstacle detecting means,
Based on the signal from the obstacle recognizing means and the detectable area calculated by the detectable area calculating means, an obstacle state when the obstacle is excluded from the target is determined by: (B) departure to the right lane or left lane of the detectable area, (c) departure far from the detectable area, (d) detection in the own lane Further comprising an obstacle state estimating means for estimating that the vehicle has left the possible area,
The operation reaction force correction means reduces the operation reaction force of the vehicle operation device in a fifth decrease pattern when the obstacle is not detected in the detectable region (a). When the vehicle departs outside the detectable area in the own lane, the operation reaction force of the vehicle operating device is reduced in the sixth decreasing pattern, and (b) the vehicle departs to the right or left lane in the detectable area. Or (c) when the vehicle departs far from the detectable region, the operation reaction force of the vehicle device is reduced in a decrease pattern according to the driver's intention estimated by the intention estimating means. Driving operation assist device. The vehicle driving assist device according to claim 18,
The fifth decrease pattern is such that the operation reaction force is gradually decreased at a fifth speed after a predetermined time delay after the obstacle becomes out of target,
The sixth decrease pattern is that the operation reaction force is gradually reduced at a sixth speed higher than the fifth speed after a predetermined time delay after the obstacle is excluded from the target. Driving operation assisting device for vehicles. The vehicle driving assist device according to claim 18,
The intention estimating means is configured to determine whether the obstacle is (b) a right lane or a left lane of the detectable area based on a signal from the obstacle state estimating means and an estimation result by the traveling position recognizing means. When the driver departs from the lane or (c) departs far from the detectable area, the driver's intention is determined by (A) cruising to maintain the current driving state, (B) passing the obstacle, (C) ) It is estimated that the vehicle follows the obstacle, or (D) non-acceleration.
The operation reaction force correction means reduces the operation reaction force of the vehicle operation device in a seventh decreasing pattern when the driver's intention is (A) cruising, and (B) when the driver intends to overtake, In a decrease pattern, the operation reaction force of the vehicle operation device is reduced in a ninth decrease pattern. In the case of (C) following, the operation reaction force of the vehicle operation device is reduced in a ninth reduction pattern. A vehicle driving assist system for reducing an operation reaction force of the vehicle equipment in a tenth decreasing pattern. The vehicle driving assist device according to claim 20,
The seventh decreasing pattern gradually reduces the operation reaction force at a seventh speed when the obstacle is out of target.
The eighth decrease pattern is such that, when the obstacle is out of target, the operation reaction force is gradually reduced at an eighth speed higher than the seventh speed,
The ninth decrease pattern is such that when the obstacle is out of target, the operation reaction force is gradually increased at a ninth speed higher than the seventh speed and lower than the eighth speed. Drop,
The tenth decrease pattern is characterized in that, when the obstacle is out of scope, the operation reaction force is gradually reduced at a tenth speed lower than the seventh speed. Operation assistance device. The vehicle driving assist device according to claim 15,
The operation reaction force correction unit reduces the operation reaction force according to the magnitude of the operation reaction force of the vehicle operation device when the obstacle detected by the obstacle detection unit is excluded from the target. A driving operation assisting device for a vehicle, characterized by changing a decrease pattern at the time. The vehicle driving assist system according to claim 22,
The operation reaction force correction means sets the decrease pattern so that the operation reaction force becomes equal to or less than a predetermined value after a predetermined time from when the obstacle is excluded from the target. apparatus. The vehicle driving assist system according to any one of claims 1 to 23,
The vehicle operation device is an accelerator pedal, wherein the vehicle operation device is an accelerator pedal. A vehicle comprising the vehicle driving assist system according to any one of claims 1 to 24.

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