JP3596015B2 - Automatic piano - Google Patents

Description

この数８によって離鍵開始時刻ｔ_０Ｎを求め、この時刻から、数６で示される軌道に従って鍵を駆動すれば、鍵は離鍵時刻ｔｋＮにおいて離鍵リファレンスポイントＸｒＮに達し、記録時の離鍵状態を忠実に再現することができる。
なお、時刻ｔ_０から速度Ｖ_０Ｎ（＝ｖｋＮ：離鍵速度）で鍵駆動するように制御（速度制御）しても上記と同様の結果を得ることができる。
【００５１】
▲３▼交差時の軌道データ作成
押鍵軌道および離鍵軌道は上述のようにして作成されるが、鍵の操作には、離鍵の途中から次の押鍵に移ったり、あるいは、押鍵の途中から離鍵される場合がある。このような場合においては、作成した押鍵軌道と離鍵軌道とが交差する。例えば、図９はこのような軌道の交差状態を示しており、図示の状態では、時刻ｔ_０から時刻ｔｃまで押鍵が行われ、時刻ｔｃから時刻ｔ_４まで離鍵が行われている。このとき、上述の方法によって生成される押鍵軌道は、時刻ｔ_０にレスト位置Ｘ_０を離れ、時刻ｔ_３においてエンド位置Ｘｅに達する軌道であり、また、離鍵軌道は時刻ｔ_０Ｎにエンド位置Ｘｅを離れ、時刻ｔ_４においてレスト位置Ｘ_０に達する軌道である。
【００５２】
ここで、交差する時刻ｔｃを求めることができれば、ｔ_０〜ｔｃまでは押鍵軌道に基づいて鍵１を制御し、ｔｃ〜ｔ_４までは離鍵軌道に基づいて鍵を制御すればよい。ここで、図９に示すような、押鍵の後に発生した離鍵の軌道が交差する場合は、交差時刻ｔｃは次のようにして求めることができる。
【００５３】
【数９】

なお、数９におけるｔ_３は、次式により算出される。
【００５４】
【数１０】
ｔ_３＝ｔ_０＋（Ｘｅ−Ｘ_０）／Ｖ_０
また、離鍵の後に発生した押鍵の軌道が交差する場合も、２つの直線軌道の交点を求めればよいので、上記と同様の考え方により交差時刻を求めることができる。
このようにして、交差時刻を求め、押鍵軌道と離鍵軌道を組み合わせることにより、交差時の軌道データを作成する。
以上が、再生前処理部１０における軌道データの作成であり、このようにして作成された軌道データは、図６に示すモーションコントローラ１１に供給される。モーションコントローラ１１においては、作成された軌道データに基づいて、各時刻における鍵１の位置に対応した位置制御データ（Ｘ）を作成し、サーボコントローラ１２に供給する。
【００５５】
サーボコントローラ１２は、位置制御データ（Ｘ）に応じた励磁電流をソレノイド５に供給するとともに、ソレノイド５から供給されるフィードバック信号と制御データ（Ｘ）を比較し、両者が一致するようにサーボ制御を行う。
【００５６】
（ロ）第２実施例の動作
始めに、記録動作について説明する。まず、演奏者によって演奏が行われると、
演奏記録部３０がセンサＳＥ１，ＳＥ２の出力信号に基づいて打弦速度および打弦時刻を検出するとともに、センサ２５の出力信号に基づいて離鍵時刻および離鍵速度を検出する。これらの情報は、記録後処理部３１において正規化処理された後に、演奏情報としてフロッピーディスク等の記録媒体に記録される。
【００５７】
次に、再生動作について説明すると、まず、再生前処理部１０は、記録媒体から演奏情報を読み出し、その中の打弦時刻データおよび打弦速度データに基づいて、押鍵軌道を作成する。
作成された押鍵軌道データは、モーションコントローラ１１に供給され、ここで、位置制御データ（Ｘ）に変換される。すなわち、押鍵開始時刻ｔ_０になると、数３に示される軌道データがモーションコントローラ１１に供給され、モーションコントローラ１１は、数３のＸを時間経過とともに順次演算し、位置制御データ（Ｘ）を作成する。この位置制御データ（Ｘ）は、サーボコントローラ１２に供給され、これにより、数３のＸに対応した励磁電流がソレノイド５に供給される。この場合、サーボコントローラ１２は、ソレノイド５のフィードバック信号と位置制御データ（Ｘ）とを比較し、両者が一致するように励磁電流を制御するから、ソレノイド５のプランジャの突出量は、数３のＸに対応したものとなる。したがって、鍵１は数３で示される直線軌道に従って押下されていき、リファレンスポイントＸｒにおいてリファレンス速度Ｖｒを有する運動を行う。これにより、記録時の打弦強度を忠実に再現する打弦が行われる。
【００５８】
次に、再生前処理部１０は、演奏情報の中の離鍵時刻データ、離鍵速度データに応じて、離鍵軌道を作成し、モーションコントローラ１１に供給する。モーションコントローラ１１は、上述の場合と同様にして、数６のＸＮを時間の経過に応じて順次演算し、位置制御データ（Ｘ）を作成し、サーボコントローラ１２に供給する。この結果、サーボコントローラ１２は数６に対応した励磁電流制御を行い、鍵１は数６で示される直線軌道に従ってレスト位置Ｘ_０に戻っていく。これにより、鍵１の運動は、離鍵リファレンスポイントＸｒＮにおいて離鍵リファレンス速度ＶｒＮを有するものとなり、記録時の離鍵状態が忠実に再現される。一方、連打等が行われ、押鍵軌道と離鍵軌道が交差するときは、再生前処理部１０が数１０によって交差時刻ｔｃを演算し、この時刻を境に、押鍵軌道と離鍵軌道を切り換えてモーションコントローラ１１に供給する。これにより、鍵１は押鍵軌道の途中から離鍵軌道に、あるいは離鍵軌道の途中から押鍵軌道に切り換えられ、いわゆる、ハーフストロークの奏法に従った運動を行う。
【００５９】
Ｃ：第３実施例
（イ）第３実施例の構成
次に、この発明の第３の実施例について説明する。この実施例が前述した第２の実施例と異なる点は、演奏記録部３０において、打弦速度とともにキーオン速度も検出する点と、再生前処理部１０において放物線の軌道データを作成する点である。そこで、説明の簡略化のため、第３実施例の構成については、第２実施例の構成を示す図６を兼用して説明する。
【００６０】
この実施例における演奏記録部３０は、キーセンサ２５内の上方のフォトセンサが遮光されてから下方のフォトセンサが遮光されまでの時間を計測し、ここからキーオン速度Ｖｋを検出する。また、下方のフォトセンサが遮光された時刻をキーオン時刻ｔｋ_２として検出する。これらのデータは、打弦速度等のデータと共に、記録後処理部３１を介して記録媒体に書き込まれる。
また、この実施例における再生前処理部１０は、押鍵時の鍵軌道として放物線、離鍵の鍵軌道として直線を想定するので、次のような手法で軌道データの作成を行う。
【００６１】
▲１▼押鍵時の軌道データ作成
押鍵軌道を次のように規定する。
【００６２】
【数１１】
Ｘ＝ａ／２・ｔ^２＋ｂ・ｔ＋ｃ
ここで、ａは加速度であり、次式によって求める。
【００６３】
【数１２】
ａ＝（Ｖｒ−Ｖｋ）／（ｔｒ−（ｔｋ_１＋ｔｋ_２）／２）
数１２におけるリファレンス速度Ｖｒは、前述の実施例と同様に、数１を用いて打弦速度から求める。また、ｔｋ_１は、次式によって求めることができる。
【００６４】
【数１３】
ｔｋ_１＝ｔｋ_２−Ｘｄ／Ｖｋ
ここで、Ｘｄは、キーセンサ２５内の２つのセンサの取り付け間隔である。また、図１０は、この実施例における放物線軌道を示す図であり、図において、Ｘｋ_２、Ｘｋ_１はキーセンサ２５内の２つのセンサの取り付け位置である。この図からも判るように、キーオン速度Ｖｋは、シャッタ２６がＸｋ_１とＸｋ_２の間を通過する間の平均速度であり、放物線軌道においては、中間時刻である時刻（ｔｋ_１＋ｔｋ_２）／２における速度である。
前述した数１２は、リファレンス速度Ｖｒとキーオン速度Ｖｋの速度差を、リファレンス時刻ｔｒと中間時刻（ｔｋ_１＋ｔｋ_２）／２の時間差で除したもので、言い替えれば、リファレンスポイントＸｒとセンサ中間点との間の速度変化から加速度を算出するものである。なお、加速度一定という推定のもとでは、任意の２点間の速度変化を基にして加速度を検出することができる。
【００６５】
以上のことから判るように、演奏データ中の打弦時刻と打弦速度から、リファレンス時刻ｔｒとリファレンス速度Ｖｒが求められ、さらに、キーオン速度Ｖｋとキーオン時刻ｔｋ_２を参照して加速度ａが求められる。
したがって、あとは押鍵開始時刻と初速度が求められれば、図１０に示す放物線軌道に沿ってキーを駆動できることになる。次に、これらの求め方について説明する。
まず、図１１に示すように、押鍵開始時刻をｔ_０、初速度をＶ_０とすれば、数１１における係数ｂは、
【００６６】
【数１４】
ｂ＝Ｖ_０−ａ・ｔ_０
と表され、また、数１１における定数ｃは、
【００６７】
【数１５】
ｃ＝Ｘ_０−（ａ／２）・ｔ_０ ^２＋ｂ・ｔ_０
と表される（ただし、数１５におけるＸ_０は前述のようにレスト位置）。
ここで、押鍵開始時刻を基準（＝０）にした場合のリファレンス時刻をｔｒ’とし、さらに、数１４、数１５を用いて、数１１をリファレンスポイントＸｒにおける式に書き直すと次式になる。
【００６８】
【数１６】
Ｘｒ＝（ａ／２）・ｔｒ’^２＋Ｖ_０・ｔｒ’＋Ｘ_０
ここで、リファレンス速度Ｖｒは、
【００６９】
【数１７】
Ｖｒ＝ａ・ｔｒ’＋Ｖ_０
と表すことができるから、この関係を数１６に代入して整理すると、
【００７０】
【数１８】
０＝（ａ／２）・ｔｒ^２−Ｖｒ・ｔｒ’−（Ｘ_０−Ｘｒ）
となり、ここから、ｔｒ’を求めると、
【００７１】
【数１９】
ｔｒ’＝（Ｖｒ−（Ｖｒ^２＋２ａ（Ｘ_０−Ｘｒ））^１／２）／ａ
となる。したがって、加速度ａ、リファレンス速度Ｖｒ、リファレンスポイントＸｒ、およびレスト位置Ｘ_０が既知であれば、鍵が押鍵開始時からリファレンスポイントＸｒに至るまでの時刻ｔｒ’が求められる。また、リファレンス時刻ｔｒと押鍵開始時刻ｔ_０の関係は、
【００７２】
【数２０】
ｔｒ’＝ｔｒ−ｔ_０
であるから、数２０を用いて、押鍵開始時刻ｔ_０が求められる。
また、数１６に数１７を代入して初速度Ｖ_０について整理して解けば、
【００７３】
【数２１】
Ｖ_０＝（Ｖｒ^２＋２ａ（Ｘ_０−Ｘｒ））^１／２
となり、これにより初速度Ｖ_０を求めることができる。
したがって、以上のようにして求めた初速度Ｖ_０、加速度ａを、数１１に代入して軌道を求め、押鍵開始時刻ｔ_０からその軌道に従って鍵を駆動することにより、打弦時刻と打弦速度とを正確に再現することができる。しかも、人間の鍵操作に近い放物線軌道なので、演奏者の微妙なニュアンスまで表現することが可能になる。
なお、時刻ｔ_０から初速度Ｖ_０で鍵を駆動し、後は、加速度ａに対応した速度変化分を用いて速度制御を行っても、上記と同様の効果が奏することができる。
【００７４】
▲２▼離鍵時の軌道データ作成
離鍵については、直線軌道を想定するので、前述した第２実施例と同様の離鍵軌道データ作成を行う。
【００７５】
▲３▼交差時の軌道データ作成
この実施例における押鍵軌道と離鍵軌道の交差は、放物線軌道と直線軌道との交差であるので、交差時刻ｔｃは、次のようにして求めることができる。
【００７６】
【数２２】
ｔｃ＝（−Δｂ＋（Δｂ^２−２・Δａ・Δｃ）^１／２）／Δａ
ただし、数２２におけるΔａは、
【００７７】
【数２３】
Δａ＝ａ−ａＮ
であり、ａＮは、離鍵時の加速度である。この実施例の場合は、離鍵時の加速度は０であるので、Δａ＝ａ（押鍵時の加速度）となる。
また、数２２におけるΔｂは、
【００７８】
【数２４】

であり、Δｃは、
【００７９】
【数２５】

である。
このようにして、交差時刻ｔｃを求め、押鍵軌道と離鍵軌道を組み合わせることにより、交差時の軌道データを作成する。
【００８０】
以上が、第３実施例における再生前処理部１０の軌道データ作成処理である。このようにして作成された軌道データは、図６に示すモーションコントローラ１１に供給され、モーションコントローラ１１においては、作成された軌道データに基づいて、各時刻における鍵１の位置に対応した位置制御データ（Ｘ）を作成し、サーボコントローラ１２に供給する。このモーションコントローラ１１とサーボコントローラ１２の構成は、第２実施例と同様になっている。
【００８１】
（ロ）第３実施例の動作
次に、第３実施例の動作について説明するが、概ね、第２実施例の動作と同じであるため、異なる点だけを説明する。
まず、記録動作は、演奏記録部３０がセンサ２５の出力信号に基づいてキーオン時刻およびキーオン速度をも検出し、記録後処理部３１において正規化処理された後に、演奏情報の一つとしてフロッピーディスク等の記録媒体に記録される。
【００８２】
次に、再生動作について説明すると、まず、再生前処理部１０は、記録媒体から演奏情報を読み出し、その中の打弦時刻データ、打弦速度データ、キーオン速度データおよびキーオン時刻データに基づいて、放物線の押鍵軌道を作成する。作成された放物線の押鍵軌道データは、モーションコントローラ１１に供給され、ここで、位置制御データ（Ｘ）に変換される。すなわち、押鍵開始時刻ｔ_０になると、数１１に示される軌道データがモーションコントローラ１１に供給され、モーションコントローラ１１は、数１１のＸを時間経過とともに順次演算し、位置制御データ（Ｘ）を作成する。この位置制御データ（Ｘ）は、サーボコントローラ１２に供給され、これにより、数３のＸに対応した励磁電流がソレノイド５に供給される。この場合、サーボコントローラ１２は、ソレノイド５のフィードバック信号と位置制御データ（Ｘ）とを比較し、両者が一致するように励磁電流を制御するから、ソレノイド５のプランジャの突出量は、数１１のＸに対応したものとなる。したがって、鍵１は数１１で示される放物線軌道に従って押下されていき、リファレンスポイントＸｒにおいてリファレンス速度Ｖｒおよび加速度ａを有する運動を行う。この結果、記録時の打弦強度を忠実に再現する打弦が行われる。しかも、人間の演奏状態に近い放物線軌道により、加速度をも再現するので、演奏の微妙なニュアンスも再現される。また、押鍵軌道と離鍵軌道が交差するときは、再生前処理部１０が数２１によって交差時刻ｔｃを演算し、この時刻を境に、押鍵軌道と離鍵軌道を切り換えてモーションコントローラ１１に供給する。これにより、鍵１は放物線の押鍵軌道の途中から直線の離鍵軌道に、あるいは直線の離鍵軌道の途中から放物線の押鍵軌道に切り換えられ、いわゆる、ハーフストロークの奏法に従った運動を行う。
【００８３】
ここで、図１２に本実施例によって鍵駆動した場合の実験例を示す。この図１２に示す３つのグラフは、いずれも横軸が時間であり、縦軸が鍵のレスト位置Ｘ_０からの移動量を示している。
この図に示す（イ）は、演奏者が実際に演奏を行った場合の鍵の軌道を示しており、図に示す時刻ｔ_１０、ｔ_１１の付近はハーフストローク奏法のために、鍵がレスト位置Ｘ_０に戻る前に次の押鍵動作に入っている。また、時刻ｔ_１２付近は、鍵は動いているが打弦は行われなかった部分である。
また、図１２（イ）に示す演奏から得られる打弦時刻、打弦速度、キーオン時刻、キーオン速度、離鍵時刻および離鍵速度を基にして、本実施例において再現した押鍵軌道および離鍵軌道が同図（ハ）に示す軌道である。また、同図（ロ）は、同図（イ）および（ハ）に示す２つの軌道を重ねたものであり、両者が良く一致していることが判る。例えば、ハーフストロークの部分については、再生軌道もハーフストローク軌道になっており、打弦が行われなかった時刻ｔ_１２の部分については、再生軌道は鍵を押し切った状態が継続されている。
【００８４】
また、図１３は、図１２の一部を拡大したものであり、この図からも実際の演奏による鍵軌道と、実施例において再現した鍵軌道との一致性が確認される。なお、実際の演奏による鍵軌道に対して、実施例で再現した鍵軌道は揺らぎが少なく一見単純に見えるが、図１２（イ）の軌道に含まれる揺らぎは、演奏者の意図とは違った部分（ミスによる部分、もしくは、アクション機構特性によって生じる演奏に関係しない部分）がほとんどである。したがって、実施例による軌道は、演奏者の意図とは違った部分を除外し、理想に近づいた軌道であると言える。
【００８５】
（ハ）第３実施例の変形
▲１▼ダンパー離弦タイミングの再現
鍵を押下していくと、まず、ダンパー６（図６参照）が弦から離れ、次いで、ハンマ２が打弦を行うことは周知の通りである。この場合、ダンパー６が弦から離れても、打弦が行われるまでは音は発生しないから、ダンパー６の離弦を正確に再現しても意味がないという考えもある。しかしながら、複数の鍵を同時あるいは近接したタイミングで押鍵する場合などには、他の弦の振動や共鳴の影響のために、打弦前であっても、ダンパーが離れていれば、その弦が振動することがある。したがって、演奏における他の弦の影響を忠実に再現するために、ダンパーの離弦タイミングを正確に再現することも重要であると言える。
そこで、以下のようにして、ダンパー離弦タイミングを推定する。まず、前述のように、キーオン時刻をｔｋ_２、キーオン速度をＶｋとし、キーオン位置（鍵１に設けられたシャッタ２６がキーセンサ２５内の下方のフォトセンサを遮光したときの鍵の位置）をＸｋ_２とする。次に、図１４に示すように、ダンパーの離弦に対応する鍵の位置をＸ_１とし、キーオン速度Ｖｋの傾きに沿って直線を引く。そして、この直線と位置Ｘ_１との交点の時刻をダンパー離弦時刻ｔ_１と推定する。すなわち、ダンパ離弦時刻ｔ_１は次式によって求められる。
【００８６】
【数２６】
ｔ_１＝ｔｋ_２−（Ｘｋ_２−Ｘ_１）／Ｖｋ
以上のようにして、ダンパー離弦時刻ｔ_１が求められれば、前述の各実施例と同様にしてリファレンス速度Ｖｒおよびリファレンス時刻ｔｒを求め、これらを満たす放物線軌道を求める。この放物線軌道を図１５に示す。この軌道は、次のように表される。
【００８７】
【数２７】
Ｘ＝（（（Ｘ_１−Ｘｒ）−Ｖｒ・（ｔ_１−ｔｒ））／（ｔ_１−ｔｒ）^２）・ｔ^２＋Ｖｒ・ｔ
したがって、数２７に示される軌道にしたがって、ソレノイドの励磁電流を制御すれば、ダンパー離弦時刻を正確に再現することができる。なお、励磁電流の制御は、前述した各実施例と同様に行えばよい。
【００８８】
▲２▼加速度、初速度の固定
第３実施例においては、押鍵時の加速度ａと初速度Ｖ_０の双方を演算によって求めるようにしたが、いずれか一方を固定値にして、計算を簡略化してもよい。この場合の固定値は、実験等を繰り返すことによって、統計的に適切な値を決めることが望ましい。
例えば、加速度ａを固定する場合には、ａ＝２．５ｍ／ｓ^２に設定すると、比較的良好な結果が得られることが判った。ここで、ａ＝２．５ｍ／ｓ^２にした場合の実験結果を図１６に示す。
【００８９】
この図に示す（イ）は、演奏者が実際に演奏を行った場合の鍵の軌道を示しており、（ハ）は同図（イ）に示す演奏から得られる打弦時刻、打弦速度を基にするとともに、加速度を固定して再現した押鍵軌道を示す。すなわち、前述した数１１に示す軌道における加速度ａの値を固定し、数１２に示す加速度算出を省略して押鍵軌道を求めたものである。なお、離鍵軌道は、直線軌道であるため、前述の実施例と同様である。
また、同図（ロ）は、同図（イ）および（ハ）に示す２つの軌道を重ねたものであり、両者が良く一致していることが判る。例えば、ハーフストロークの部分についても、良好な一致性が認められる。なお、図１７（イ）、（ロ）、（ハ）は、図１６（イ）、（ロ）、（ハ）の軌道を一部拡大したものである。
以上のように加速度を固定すると、演算が省略できるため、処理速度が早くなるとともに、キーオン速度Ｖｋおよびキーオン時刻ｔｋ２の検出が不要になるため、装置構成としては第２実施例の構成であっても実施することができる。
【００９０】
次に、初速度Ｖ_０を固定した場合について説明する。この場合には、数２０の演算を省略し、予め設定した初速度Ｖ_０を用いて数１１に示す軌道を演算すればよい。
ここで、初速度Ｖ_０を０．１ｍ／ｓにした場合の実験結果を図１８に示す。
この図に示す（イ）は、演奏者が実際に演奏を行った場合の鍵の軌道を示しており、（ハ）は同図（イ）に示す演奏から得られる打弦時刻、打弦速度を基にするとともに、初速度Ｖ_０を固定して再現した押鍵軌道を示す。すなわち、前述した数２０の初速度演算を省略して初速度Ｖ_０を固定し、この条件の基で数１１に示す押鍵軌道を求めたものである。なお、離鍵軌道は、直線軌道であるため、前述の実施例と同様である。そして、同図（ロ）は、同図（イ）および（ハ）に示す２つの軌道を重ねたものであり、両者が良く一致していることが判る。なお、図１９（イ）、（ロ）、（ハ）は、図１８（イ）、（ロ）、（ハ）の軌道を一部拡大したものである。
【００９１】
Ｄ：変形例
この発明においては、上述した各実施例に対し、以下に述べる種々の変形が可能である。
▲１▼サーボ制御の変形
上述した各実施例においては、モーションコントローラ１１とサーボコントローラ１２によって位置サーボ制御を行っていたが、これに代えて、第２実施例では速度を指示する速度サーボ制御を行っても良い。すなわち、モーションコントローラ１１が押鍵（あるいは離鍵）開示時刻において初速度を指示し、サーボコントローラ１２は鍵１が与えられた速度を保つようにサーボ制御を行うようにしてもよい。また、第３実施例においては、加速度制御を行うようにしてもよい。すなわち、モーションコントローラ１１が押鍵開始時刻において初速度を指定し、以後は時間の経過とともに速度の変化分を順次指示する。そして、サーボコントローラ１２は、速度変化分を累算して、現時点の速度を算出し、鍵１の速度が累算速度に一致するようにサーボ制御を行う。
【００９２】
▲２▼推定した加速度情報の電子楽器への応用
第３実施例において推定した加速度ａは、自動ピアノの押鍵制御に限らず、電子楽器等の楽音制御に用いることができる。すなわち、加速度の推定は、押鍵速度情報と打弦速度情報がそれぞれ１以上あれば可能であるから、これらの情報を基に加速度を推定し、それを楽音制御情報として用いることができる。例えば、楽音波形を複数記憶し、これらの波形を音の強さや、高さに応じて選択して読み出す電子楽器があるが、この電子楽器に、さらに加速度情報に応じた波形選択を行わせると、発生楽音の表情がいっそう豊かになるという利点が得られる。
【００９３】
さらに、第３実施例においては、キーオン速度Ｖｒとリファレンス速度Ｖｒの偏差に基づいて加速度を推定したが、打弦速度とキーオン速度の差から推定するようにしてもよい。また、打弦速度を２カ所以上で検出するように、これらの速度差から推定してもよく、さらに、押鍵速度を２カ所以上で検出するようにし、これらの速度差から検出してもよい。
【００９４】
また、加速度の推定は、記録時に行っても、再生時に行ってもよく、これらの中間において行っても良い。例えば、記録媒体から演奏情報を読み取る際に、加速度推定を行って他の記録媒体に記録するようにしてもよい。
【００９５】
▲３▼リファレンスポイントＸｒにおける運動属性の変形
上述した各実施例においては、リファレンスポイントＸｒにおける鍵の速度や加速度を再現するようにしたが、鍵の運動を一意的に再現できるのであれば、その他の運動属性を再現するようにしてもよい。例えば、速度、加速度、力のいずれか、あるいは、これらの組み合わせを用いても良い。
【００９６】
▲４▼離鍵時の加速度軌道
上述した各実施例においては、離鍵時の軌道は全て直線軌道であったが、これを加速度軌道としてもよい。この場合には、離鍵速度を２カ所以上で測定するようにセンサを追加し、得られた速度の変化から加速度を推定するように構成すればよい。例えば、キーセンサ２５内のフォトセンサの数を増やし、演奏記録部３０がこれらのセンサの出力信号から２カ所以上の離鍵速度を検出するようにすればよい。
さらに、押鍵時と離鍵時の軌道を直線とするか放物線とするかは、任意に組み合わせることが可能である。
【００９７】
▲５▼開平演算態様
第３実施例における初速算出演算（数２０）および押鍵開始時刻算出演算（数１８、１９）は、開平演算が入るが、ソフトウエア上の演算速度が問題になる場合は、例えば、２分探索法を用いて、正数演算をしてもよい。
【００９８】
▲６▼弱音の再生
実際の押鍵操作においては、強打よりも弱打において放物線軌道をとる傾向が強く、直線軌道での再現では再現性が悪化してくる。特に、最弱打（ｐｐｐｐ）に近い押鍵を直線軌道で再現しようとすると、ピアノのアクション部の構造などの理由から、ハンマへの力伝達が行われず不安定な打弦となることがある。そこで、第２実施例においては、弱音だけを検出して放物線軌道で再現するようにし、その他の音は直線軌道で再現するように構成してもよい。すなわち、再生前処理部１０において、打弦速度データを所定のしきい値で振り分け、弱音と判定された音に対しては、予め設定した加速度ａを用いて放物線軌道を算出し、これによって鍵を駆動する。
【００９９】
▲７▼打弦時刻、打弦速度の代用
例えば、特開平１−２３９５９４号では、押鍵速度から打弦速度を推定して記録するようにしているが、このように、打弦速度に代わるデータが記録されている場合は、前述した各実施例において、それを用いることも可能である。したがって、ＭＩＤＩ信号中のキーオン速度（キーベロシティ）のように、打弦速度に対応するデータが記録されている場合においては、これを用いて軌道演算を行うことができる。打弦時刻についても、これに代わるデータがあれば、代用することができる。要は、発音時刻や発音強度に関連したデータ（発音時刻を示す発音時刻情報および発音強度を示す発音強度情報）であれば、用いることができる。
【０１００】
【発明の効果】
以上説明したように、この発明によれば、鍵の軌跡の所定点（リファレンスポイント）における運動属性が再現されるように鍵を駆動するので、ハンマの挙動を忠実に再現することができ、打弦速度を正確なものとすることができる。また、前記所定点を通る直線軌道あるいは放物線軌道に沿って鍵を駆動すれば、所定点における鍵の運動属性は確実に再現されるとともに、特に、放物線軌道を採用した場合は、人間の鍵操作軌道に近いため、演奏のニュアンスをも再現することができる。
【図面の簡単な説明】
【図１】この発明の第１実施例の構成を示すブロック図である。
【図２】図２はリファレンスポイントを９．５ｍｍに設定したときの鍵速度と打弦速度の関係を示す図である。
【図３】リファレンス時間差Ｔｒと打弦速度との関係を示す図である。
【図４】図３を縮尺２倍にした図である。
【図５】図３を縮尺４倍にした図である。
【図６】第２実施例の構成を示すブロック図である。
【図７】鍵の押鍵軌道（直線軌道）を示す図である。
【図８】数６で示される軌道を示す図である。
【図９】押鍵の後に発生した離鍵の軌道が交差する場合を示す図である。
【図１０】第３実施例で用いる放物線軌道を示す図である。
【図１１】第３実施例における押鍵開始時刻の算出を説明するための図である。
【図１２】第３実施例において、鍵駆動した場合の実験例を示す図である。
【図１３】図１２の一部を拡大した図である。
【図１４】ダンパーの離弦時刻推定方法を説明するための図である。
【図１５】ダンパー離弦時刻を再現した場合の放物線軌道を示す図である。
【図１６】第３実施例において加速度を固定した場合の実験結果を示す図である。
【図１７】図１６の一部を拡大した図である。
【図１８】第３実施例において初速度を固定した場合の実験結果を示す図である。
【図１９】図１８の一部を拡大した図である。
【図２０】一般的な自動ピアノの構成を示す概略図である。
【符号の説明】
５……ソレノイド（鍵駆動手段：サーボ駆動手段）、１０……再生前処理部（運動属性算出手段：軌道算出手段：弱音抽出手段）、１１……モーションコントローラ（鍵駆動手段：指令値出力手段）、１２……サーボコントローラ（鍵駆動手段：サーボ駆動手段）。[0001]
[Industrial applications]
The present invention relates to, for example, an automatic piano for automatically driving a keyboard to perform.ToRelated.
[0002]
[Prior art]
In an automatic piano, when a key is driven by exciting a solenoid, a hammer is rotated and a string is struck accordingly. The strength of the hammer striking corresponds to the driving speed of the key, and the driving speed of the key corresponds to the current supplied to the solenoid. Therefore, by controlling the amount of power supplied to the solenoid, it is possible to control the strength of the string striking, that is, the magnitude of the generated musical sound.
[0003]
By the way, in an automatic piano, when recording performance information, the speed of a hammer immediately before striking is detected, and this is recorded as data indicating the striking strength (hereinafter referred to as striking strength data). The time of passing the string striking position is recorded as string striking time data. Note that the string striking time data is generally recorded as time data (relative time data) indicating an interval from the immediately preceding sound, but an absolute time from the start of the performance may be recorded.
When reproducing the recorded performance information, a current corresponding to the stringing strength data in the performance information is supplied to the solenoid. Further, the power supply amount control to the solenoid is generally performed by pulse width modulation (PWM).
[0004]
In this case, power is supplied to the solenoid a little before the stringing timing indicated by the stringing time data, in anticipation of the time difference from the start of driving the key to the actual stringing of the hammer. Also, since the time from the start of key depression to the striking of a strong sound differs from that of a weak sound, an automatic piano has been developed in which the power supply timing to the solenoid is adjusted in accordance with the string striking strength data.
[0005]
It should be noted that there is a type in which the hammer speed is estimated from the key pressing speed when recording the performance data (Japanese Patent Laid-Open No. 1-239594). In this case, the estimated hammer speed is recorded as stringing strength data.
[0006]
[Problems to be solved by the invention]
By the way, the above-described conventional automatic piano performs an open loop control in which a current corresponding to the stringing strength data is supplied to the solenoid at a timing corresponding to the stringing time data. At times, it was as simple as depressing a key with a force corresponding to the stringing strength data.
However, the keyOrbit(In this caseOrbitConsidering the position change with the passage of time), controlling only the pressing force at the start of key pressing does not mean that the key trajectory at the time of performance is reproduced, and therefore, the string striking at the time of recording is performed. The speed could not be accurately reproduced.
[0007]
In addition, the performance by the performer does not merely control the pressing force at the start of key pressing, but also expresses the musical tone from the start of key pressing to key release to express the subtle nuance of the music. Perform the operation according to. Therefore, simply controlling the pressing force at the start of key depression cannot accurately reproduce the expression of the musical tone, resulting in a mechanically dull performance.
[0008]
The present invention has been made in view of the above-described circumstances, and has as its first object to provide an automatic piano that can accurately reproduce a string striking speed. Another object of the present invention is to provide an automatic piano capable of expressing a subtle nuance of performance..
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the invention described in claim 1,An automatic piano in which a hammer is rotated by pressing a key and a sound is produced by striking a string by the hammer.Pronunciation time information indicating the pronunciation time andAs the strength of the hammer striking the stringsSupply means for supplying pronunciation intensity information indicating pronunciation intensity;The motion attribute of the key at a predetermined point within a range from the key rest position to the end position, where the key speed and the sounding intensity of the hammer striking a string indicate a specific correspondence. From the sounding intensity indicated by the sounding intensity information and the sounding time indicated by the sounding time information, using the correspondence.Exercise attribute calculating means,SaidDriving means for driving the key;Control means for controlling driving of the key by the driving means so that the key has the motion attribute determined at the predetermined point; andIt is characterized by having.
[0010]
In the invention described in claim 2,An automatic piano in which a hammer is rotated by pressing a key and a sound is produced by striking a string by the hammer.Pronunciation time information indicating the pronunciation time andAs the strength of the hammer striking the stringsSupply means for supplying pronunciation intensity information indicating pronunciation intensity;The passing speed of the key at a predetermined point within a range from the key rest position to the end position, where the speed and the sounding intensity of the hammer striking the string show a specific correspondence, Using the correspondence relationship, the key is obtained from the sound intensity indicated by the sound intensity information, and the passing time of the key at the predetermined point is obtained from the obtained passing speed and the sound time indicated by the sound time information.Motion attribute calculation means, and the passing speed and the passage time obtained by the motion attribute calculation means are satisfied.The key trajectory is calculated as a relationship between the key position with respect to time andTrajectory calculating means for calculating a key pressing start time;SaidDriving means for driving the key;The key starts key depression from the determined key depression start time, reaches the predetermined point at the determined passage time, and has a passage speed determined when the key reaches the predetermined point. Control means for controlling driving of the key by the driving means;It is characterized by having.
[0011]
In the invention according to claim 3,An automatic piano in which a key is pressed to produce a sound by striking a string, while a key is released by a damper to suppress the string and mute the sound.Supply means for supplying key release time information indicating key release time and key release speed information indicating key release speed;The key is set in advance within a range from the key end position to the rest position, and the key is set at a predetermined point corresponding to the string suppression start point by the damper at the key release time indicated by the key release time information. Trajectory calculating means for calculating a key trajectory passing at a key release speed represented by the following equation as a relationship of a key position with respect to time, and obtaining a key release start time in the key trajectory.When,SaidDriving means for driving the key;The key is started to be released from the obtained key release start time, and at the predetermined point, at the key release time indicated by the key release time information, the key release speed is indicated by the key release speed information. Control means for controlling the driving of the key by the driving means;It is characterized by having.
[0014]
Claim4In the automatic piano according to the present invention, in the automatic piano according to the second or third aspect, the trajectory calculating means calculates a parabolic trajectory of a key that satisfies a predetermined acceleration, a passing time and a passing speed calculated by the motion attribute calculating means. It is characterized in that it is calculated.
[0015]
Claim5In the invention described in the above, the claim4In the automatic piano described above, the trajectory calculating means calculates the initial velocity of the key when calculating the parabolic trajectory.ToIt is characterized in that a preset value is used.
[0016]
Claim6In the automatic piano according to the second aspect, the automatic piano according to the second aspect further includes a weak sound extracting unit configured to compare the pronunciation intensity information with a reference value to extract a weak sound, and the trajectory calculating unit performs processing on the extracted weak sound. Calculates a parabolic trajectory of a key that satisfies a preset acceleration, the passing time and the passing speed determined by the motion attribute calculating means, and a key that satisfies the passing time and the passing speed determined by the motion attribute calculating means except for a weak sound. Is calculated.
[0018]
[Action]
Predetermined point of key locus (ReThe key is driven so that the motion attribute at the reference point is reproduced. Therefore, the behavior of the hammer can be accurately reproduced by selecting, as a predetermined point, a point having a deep correspondence with the movement of the hammer. In addition, when the key is driven along a straight orbit line or a parabola orbit passing through the predetermined point, the motion attribute of the key at the predetermined point is reliably reproduced..In addition, when a parabolic trajectory is adopted, the nuance of the performance can be reproduced because it is close to the key operation trajectory of a human..
[0019]
【Example】
A: First embodiment
(B) Control principle
(1) Reference point
FIG. 20 is a cross-sectional view showing a configuration of a main part of a general automatic piano. As shown in the figure, an automatic piano has a key 1, an action 3 for transmitting the movement of the key 1 to a hammer 2, a string 4 struck by the hammer 2, and a solenoid 5 for driving the key 1. are doing. When the plunger of the solenoid 5 protrudes, the key 1 rotates around the balance pin P, and the player's side is lowered (hereinafter, this state is called a key pressed state). Actuation causes the damper 6 to move away from the string 4 and the hammer 2 to rotate and strike the string.
On the other hand, when the player plays the string, pressing the key 1 with a finger causes the same operation as described above to be performed and the string is struck.
[0020]
In the figure, SE1 and SE2 are sensors for measuring the string striking speed. By measuring the time when the hammer 2 passes between these sensors SE1 and SE2, the speed of the hammer 2, that is, The striking speed is measured. The time at which the hammer 2 passes through the sensor SE1 is measured as the string striking time. In order to make the stringing time detected by the sensor SE1 closer to the time when the hammer 2 actually strikes the string, the sensor SE1 is provided at a position close to the stringing position of the hammer 2.
By the way, the striking speed of the hammer 2 is determined according to the speed at which the key 1 is pressed down, but the speed of the key 1 may be slow at first and gradually increased, or vice versa, and furthermore, at a substantially constant speed. It may be pushed. In this case, what is the relationship between the speed from the rest position of the key 1 (the initial position when the key 1 is not pressed) to the end position (the position where the key is fully pressed) and the stringing speed of the hammer 2? Is important. This is because, even if the key velocity (such as the initial velocity) is controlled in accordance with the string striking strength data without considering the relationship, the string striking velocity during recording cannot be reproduced.
[0021]
According to an experiment, it was found that the velocity at a certain position of the key 1 and the stringing velocity of the hammer 2 showed an extremely good correspondence. Although this position depends on the individual difference of the piano, it was a position which was pushed down about 9.0 mm to 9.5 mm from the rest position. Therefore, if the speed at which the key 1 reaches this position is controlled according to the string striking strength data, the string striking speed during recording can be faithfully reproduced. Hereinafter, the above-mentioned predetermined position is referred to as a reference point Xr.
[0022]
(2) Reference speed
Next, at the reference point Xr obtained as described above, it is necessary to set what key speed should be used to reproduce the string striking speed faithfully. In the following, the key speed at the reference point Xr is referred to as a reference speed Vr.
[0023]
Here, FIG. 2 is a diagram showing the relationship between the key speed and the string striking speed when the reference point Xr is set to 9.5 mm. In the figure, the white dots indicate the results in the case of performing the single-stroke playing method in which the key is pushed to the end position, and the black dots indicate the results in the case of performing the continuous striking method in which the key is struck without pushing the key to the end position. C1 indicates a straight line based on the first-order least squares approximation, and C2 indicates a curve based on the sixth-order least squares method.
[0024]
As is apparent from FIG. 2, the reference speed Vr can be approximated by either the straight line C1 or the curve C2. Therefore, if a function with good approximation is appropriately selected, the reference speed Vr can be determined from arbitrary stringing strength data (stringing speed information at the time of recording) using this function.
In this embodiment, a linear function approximation which is simple in calculation and has few errors is adopted. Therefore, the reference speed vr is obtained by the following equation.
[0025]
(Equation 1)
vr = α · vH + β
In Equation 1, vH is a string striking speed (string striking strength data), and α and β are constants. The constants α and β are determined by experiments or the like according to the type of piano or the like. Note that α and β fluctuate depending on where the reference point Xr is set even for the same piano.
[0026]
(3) Reference time difference
Now, the stringing time data included in the performance information is recorded as a relative time or an absolute time, as described above. The absolute string striking time of each sound at the time of reproduction is obtained. Therefore, in order to accurately perform string striking at the absolute string striking time obtained in this manner, it is necessary to determine when the key should pass through the reference point Xr.
[0027]
Here, the time difference between the time when the key 1 passes through the reference point Xr (hereinafter referred to as reference time tr) and the string striking time (more precisely, the time when the hammer passes the sensor SE immediately before the string striking position) is referred to. FIG. 3 shows the relationship between the time difference Tr and the string striking speed obtained by experiments. In FIG. 3, the white dots indicate the results obtained by the single hitting technique, and the black dots indicate the results obtained by the continuous playing technique. FIG. 4 is a diagram in which FIG. 3 is doubled in scale, and FIG. 5 is a diagram in which the scale is quadrupled. As can be seen from these figures, the relationship between the reference time difference Tr and the string striking speed is very well approximated by a hyperbola. In other words, the reference time difference Tr can be approximated by a one-variable equation using the stringing speed vH as a denominator, and is calculated by the following equation.
[0028]
(Equation 2)
Tr = − (γ / vH) + δ
Note that the constants γ and δ in Equation 2 are determined by experiments or the like according to the type of piano or the like. Note that γ and δ vary depending on where the reference point Xr is, even for the same piano. This is similar to the case of α and β in Equation 1.
[0029]
By the way, if the reference time difference Tr is obtained by the equation 2, the reference time difference Tr is obtained by subtracting the reference time difference Tr from the absolute stringing time on the reproduction side. By the process of (3), the reference point Xr, the reference speed Vr, and the reference time tr are obtained. Therefore, if the key 1 is driven so that the reference point Xr is reached at the reference time tr and the speed at that time becomes the reference speed Vr, the string striking state at the time of recording can be faithfully reproduced.
If the string is hit when the key 1 reaches the reference point Xr, the process of obtaining the reference time difference Tr becomes unnecessary.
[0030]
(4) Outline of control
As described above, if the reference speed Vr at the preset reference point Xr is obtained, the string striking speed at the time of recording can be reproduced by controlling the behavior of the key 1 accordingly.
[0031]
In this case, if the trajectory of the key from the rest position to the end position (key position with respect to the passage of time) is set, the relationship between each position and the time from the key press start position to the reference point Xr (the speed and the time) Relationship, etc.), it is understood that the position of the key may be feedback-controlled in accordance with this. In this case, for the key trajectory, for example, an arbitrary trajectory other than a linear trajectory (in the case of constant velocity motion) or a parabolic trajectory (in the case of constant acceleration motion) passing through the reference point Xr can be set. However, it is preferable to select a trajectory that has good reproducibility of the string striking state and is easy to control. In addition, depending on the trajectory to be set, it is necessary to obtain the acceleration or the like (other elements that determine the motion) at the reference point, but this may be calculated as appropriate according to the type of the trajectory.
The above is the control principle of this embodiment.
[0032]
(B) Configuration and operation of the first embodiment
Hereinafter, a configuration of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of this embodiment. The same reference numerals are given to the portions corresponding to the respective portions in FIG. 20 described above, and description thereof will be omitted.
[0033]
In FIG. 1, reference numeral 10 denotes a pre-reproduction processing unit, which is a circuit for creating key trajectory data based on performance data supplied from a recording medium or a real-time communication device. First, a reference time tr and a reference speed vr are obtained. If it is necessary to estimate the acceleration, this is calculated. Then, data indicating the key trajectory for each sound is generated according to the type of the trajectory (straight line, parabola, or any other trajectory).
Reference numeral 11 denotes a motion controller that creates data indicating the movement of the plunger of the solenoid 5 based on the trajectory data created by the playback preprocessing unit 10. Reference numeral 12 denotes a servo controller, which controls an exciting current of the solenoid 5 according to data supplied from the motion controller 11. In this case, the solenoid 5 is provided with a detection mechanism for detecting the position of the plunger, and the detected plunger position is fed back to the servo controller 12 as a feedback signal. Then, the servo controller 12 checks the data supplied from the motion controller 11 and the feedback signal from the solenoid 5 and controls the exciting current so that they match.
[0034]
According to the above-described configuration, a key trajectory passing through the reference point Xr is generated according to the string striking strength data in the performance data, and the exciting current of the solenoid 5 is controlled so that the key reproduces this trajectory.
As a result, the speed when the key 1 reaches the reference point Xr becomes a speed corresponding to the string striking speed at the time of recording (that is, the reference speed Vr), and the hammer 2 strikes the string at the same speed as at the time of recording. .
As described above, in this embodiment, a control point called a reference point is introduced, and the motion attribute of the key at this point is reproduced. Therefore, the string striking speed is faithfully reproduced without increasing the number of sensors and the like. be able to.
[0035]
B: Second embodiment
Next, a second embodiment of the present invention will be described. The control principle in the second embodiment is the same as that in the first embodiment. However, in the second embodiment, a linear trajectory is set as the key trajectory, and not only when the key is pressed but also when the key is released. Even the key is servo driven.
[0036]
(A) Configuration of the second embodiment
FIG. 6 is a block diagram showing the configuration of the second embodiment. Parts corresponding to the respective parts in FIG. 1 are denoted by the same reference numerals.
Reference numeral 26 shown in FIG. 6 is a plate-shaped shutter attached to the lower surface of the key 1. Reference numeral 25 denotes a key sensor constituted by two sets of photo sensors provided at a predetermined distance in the vertical direction. When the key 1 starts being pressed, the upper photo sensor is first shielded from light, and then the lower photo sensor is shielded from light. Is done. When the key is released, the lower photo sensor is in a light receiving state, and then the upper sensor is in a light receiving state.
[0037]
The output signal of the key sensor 25 is supplied to the performance recording unit 30, and the performance recording unit 30 measures the time from when the lower photo sensor in the key sensor 25 is in the light receiving state to when the upper photo sensor is in the light receiving state. From this, the key release speed is detected. The performance recording unit 30 processes the time at which the upper photo sensor enters the light receiving state as the key release time. Further, the performance recording unit 30 measures the time from when the sensor SE2 is shielded to when the sensor SE1 is shielded, and detects the stringing speed therefrom. Also, the time when the sensor SE1 is shielded from light is processed as the string striking time.
[0038]
That is, when the performance is started, the performance recording unit 30 detects the stringing time and the stringing speed based on the output signals of the sensors SE1 and SE2, and detects the key release time based on the output signal of the key sensor 25. And a key release speed. Each piece of information detected as described above is supplied to the post-recording processing unit 31.
[0039]
In the post-recording processing unit 31, various information supplied from the performance recording unit 30 are
After performing the normalization processing, it is supplied as performance information to an external recording medium. Here, the normalization process is a process for absorbing individual differences between pianos. In other words, the stringing speed, the stringing time, the key release speed, the key release time, and the like have a unique tendency due to the position of the sensor in each piano, a structural difference, or a mechanical error. This is processing for assuming and converting the string striking speed, string striking time, and the like in the piano.
Next, the pre-reproduction processing unit 10 according to the present embodiment will be described. In this embodiment, since a straight line is assumed as the key trajectory, the trajectory data is created by the following method.
[0040]
(1) Creating trajectory data when key is pressed
FIG. 7 is a view showing a key pressing trajectory (linear trajectory) of the key, and the rest position X₀, And reaches the end position Xe. Here, the initial velocity of the key is V₀If the position of the key is X and the time from the start of driving the key is t, the trajectory of the key is
[0041]
(Equation 3)
X = V₀・ T + X₀
It is expressed as
Also, assuming that the time when the key reaches the reference point Xr is tr ',
[0042]
(Equation 4)
Xr = V₀・ Tr '+ X₀
Since the following expression holds, the time tr 'can be obtained from the equation (4). Therefore, an absolute time at which key pressing is started (hereinafter referred to as a key pressing start time) t₀Can be obtained by the following equation.
[0043]
(Equation 5)
t₀= Tr-tr '= tr- (Xr-X₀) / V₀
Note that the reference time tr is obtained by subtracting the reference time difference Tr from the string striking time as described above. The key pressing start time t is calculated by the above equation (5).₀From this time, if the key 1 is driven in accordance with the trajectory expressed by the equation 3, the key 1 accurately reaches the reference point Xr at the reference time tr, and the speed at that time corresponds to the string striking strength data. didReThe reference speed becomes Vr.
[0044]
Since the key behavior is assumed to be a linear trajectory (constant velocity motion), the reference velocity Vr and the initial velocity V₀Are equal. Then, since the reference speed Vr is obtained by the above equation 1, the key pressing start time t obtained by the equation 5₀Even if the control is performed such that the key is driven at a constant speed vr (speed control), the same result as described above can be obtained.
[0045]
(2) Creation of orbit data at key release
Next, creation of orbit data at the time of key release will be described.
First, the key position is XN and the initial key release speed is V₀If N (<0), the time from the key release start time is tN, and the end position is Xe, the key trajectory at the time of key release is expressed by the following equation.
[0046]
(Equation 6)
XN = V₀N ・ tN + Xe
Here, FIG. 8 is a diagram showing a trajectory represented by Expression 6.
As described above, the performance recording unit 30 (see FIG. 6) measures the time from when the lower photo sensor in the key sensor 25 is in the light receiving state to when the upper photo sensor is in the light receiving state. The key speed vkN is detected, and the time at which the upper photo sensor enters the light receiving state is detected as the key release time tkN. In this case, the damper 6 at the key release time tkN is in a state of coming into contact with the string 4 and starting to attenuate the sound (the position of the photosensor is adjusted to such a state). The key release speed VkN and key release time tkN detected in this manner are recorded as data constituting performance information, respectively, and are read out during reproduction.
[0047]
Here, if the position of the key when the damper 6 contacts the string 4 is defined as the key release reference point XrN, it can be said that the key 1 has entered the key release state when the key 1 has reached the key release reference point XrN. . Therefore, if the key position is controlled so that the time at which the key 1 reaches the key release reference point XrN (hereinafter, referred to as key release reference time trN) and the key release time tkN in the performance information, accurate key release is achieved. Timing control can be performed.
[0048]
Since the speed at which the damper 6 contacts the string 4 affects the sound attenuation state, it is desirable to faithfully reproduce this. Since this speed corresponds to the key release speed VkN, after all, if the key speed at the key release reference point XrN (hereinafter, referred to as the key release reference speed VrN) exactly matches the key release speed VkN, the sound is attenuated. The state is accurately reproduced.
Here, assuming that the time at which the driving of the key starts is a reference (= 0) and the time at which the key reaches the reference point XrN is trN ',
[0049]
(Equation 7)
XrN = V₀N · trN '+ XeN
(However, V₀N = VrN = VkN)
The following relationship holds, and the time trN 'can be obtained from the equation (7). Therefore, the key release start time t is given by the following equation.₀N can be determined.
[0050]
(Equation 8)

The key release start time t is calculated by the equation (8).₀If N is obtained and the key is driven from this time according to the trajectory shown in Equation 6, the key reaches the key release reference point XrN at the key release time tkN, and the key release state at the time of recording can be faithfully reproduced. .
Note that time t₀To speed V₀Even if control (speed control) is performed so that the key is driven at N (= vkN: key release speed), the same result as described above can be obtained.
[0051]
(3) Creating orbit data at the time of intersection
The key press trajectory and the key release trajectory are created as described above.However, in key operation, there are cases where the key is moved from the middle of the key release to the next key press or the key is released from the middle of the key press. is there. In such a case, the created key press trajectory and the key release trajectory intersect. For example, FIG. 9 shows such a crossing state of the trajectories.₀From the time tc to the time tc.₄Until the key is released. At this time, the key depression trajectory generated by the above-described method is the time t₀At rest position X₀At time t₃At the end position Xe, and the key release trajectory is the time t₀N leaves the end position Xe at time t₄At rest position X₀The orbit that reaches.
[0052]
Here, if the intersection time tc can be obtained, t₀Up to tc, the key 1 is controlled based on the key depression trajectory,₄Until then, the key may be controlled based on the key release trajectory. Here, when the trajectories of a key release that occurs after a key press as shown in FIG. 9 intersect, the intersection time tc can be obtained as follows.
[0053]
(Equation 9)

Note that t in Equation 9 is₃Is calculated by the following equation.
[0054]
(Equation 10)
t₃= T₀+ (Xe-X₀) / V₀
Also, when the trajectory of a key press generated after a key release intersects, the intersection of the two linear trajectories may be obtained, so that the intersection time can be obtained in the same way as described above.
In this way, the intersection time is determined, and the key depression trajectory and the key release trajectory are combined to create the trajectory data at the time of the intersection.
The above is the creation of the trajectory data in the pre-playback processing unit 10. The trajectory data thus created is supplied to the motion controller 11 shown in FIG. The motion controller 11 creates position control data (X) corresponding to the position of the key 1 at each time based on the created trajectory data, and supplies it to the servo controller 12.
[0055]
The servo controller 12 supplies an exciting current corresponding to the position control data (X) to the solenoid 5, compares a feedback signal supplied from the solenoid 5 with the control data (X), and performs servo control so that the two coincide. I do.
[0056]
(B) Operation of the second embodiment
First, the recording operation will be described. First, when a performance is performed by a performer,
The performance recording unit 30 detects a string-strike speed and a string-strike time based on output signals from the sensors SE1 and SE2, and detects a key-release time and a key-release speed based on an output signal from the sensor 25. After the information is normalized by the post-recording processing section 31, it is recorded as performance information on a recording medium such as a floppy disk.
[0057]
Next, the reproduction operation will be described. First, the pre-reproduction processing unit 10 reads out performance information from a recording medium and creates a key-depressed trajectory based on the stringing time data and the stringing speed data therein.
The created key depression path data is supplied to the motion controller 11, where it is converted into position control data (X). That is, the key press start time t₀Then, the trajectory data shown in Expression 3 is supplied to the motion controller 11, and the motion controller 11 sequentially calculates X in Expression 3 with the passage of time to create position control data (X). The position control data (X) is supplied to the servo controller 12, whereby the exciting current corresponding to X in Expression 3 is supplied to the solenoid 5. In this case, the servo controller 12 compares the feedback signal of the solenoid 5 with the position control data (X) and controls the exciting current so that the two coincide with each other. It corresponds to X. Therefore, the key 1 is depressed according to the straight line trajectory shown in Expression 3, andReAt the reference point XrReA motion having the reference speed Vr is performed. As a result, string striking is performed that faithfully reproduces the string striking strength during recording.
[0058]
Next, the reproduction preprocessing unit 10 creates a key release trajectory according to the key release time data and the key release speed data in the performance information, and supplies the key release trajectory to the motion controller 11. The motion controller 11 sequentially calculates XN of Expression 6 as time passes, creates position control data (X), and supplies the position control data (X) to the servo controller 12 in the same manner as described above. As a result, the servo controller 12 performs the excitation current control corresponding to the equation (6), and the key 1 moves the rest position X in accordance with the linear trajectory shown in the equation (6).₀Go back to Accordingly, the movement of the key 1 has the key release reference speed VrN at the key release reference point XrN, and the key release state at the time of recording is faithfully reproduced. On the other hand, when repeated tapping or the like is performed and the key depression trajectory intersects with the key release trajectory, the reproduction pre-processing unit 10 calculates the intersection time tc by Equation 10, and from this time, the key depression trajectory and the key release trajectory. Is supplied to the motion controller 11. As a result, the key 1 is switched from the middle of the key depression trajectory to the key release trajectory, or from the middle of the key release trajectory to the key depression trajectory, and performs a motion according to a so-called half-stroke playing style.
[0059]
C: Third embodiment
(A) Configuration of the third embodiment
Next, a third embodiment of the present invention will be described. This embodiment differs from the above-described second embodiment in that the performance recording unit 30 detects the key-on speed as well as the string striking speed, and that the reproduction preprocessing unit 10 creates parabolic trajectory data. . Therefore, for the sake of simplicity, the configuration of the third embodiment will be described with reference to FIG. 6 showing the configuration of the second embodiment.
[0060]
The performance recording unit 30 in this embodiment measures the time from when the upper photo sensor in the key sensor 25 is shielded to when the lower photo sensor is shielded from light, and detects the key-on speed Vk therefrom. The time at which the lower photo sensor is shielded from light is referred to as a key-on time tk.₂Detected as These data are written on a recording medium via the post-recording processing unit 31 together with data such as the string striking speed.
In addition, since the pre-reproduction processing unit 10 in this embodiment assumes a parabola as a key trajectory at the time of key depression and a straight line as a key trajectory of key release, it generates trajectory data by the following method.
[0061]
(1) Creating trajectory data when key is pressed
The key press trajectory is defined as follows.
[0062]
[Equation 11]
X = a / 2 · t²+ B · t + c
Here, a is an acceleration, which is obtained by the following equation.
[0063]
(Equation 12)
a = (Vr-Vk) / (tr- (tk₁+ Tk₂) / 2)
The reference speed Vr in Expression 12 is obtained from the stringing speed using Expression 1, as in the above-described embodiment. Also, tk₁Can be obtained by the following equation.
[0064]
(Equation 13)
tk₁= Tk₂-Xd / Vk
Here, Xd is an attachment interval between two sensors in the key sensor 25. FIG. 10 is a diagram showing a parabolic trajectory in this embodiment.₂, Xk₁Is a mounting position of the two sensors in the key sensor 25. As can be seen from this figure, the key-on speed Vk is not₁And Xk₂And the average speed during the parabola trajectory.₁+ Tk₂) / 2.
The above-described equation (12) is obtained by calculating the speed difference between the reference speed Vr and the key-on speed Vk by using the reference time tr and the intermediate time (tk).₁+ Tk₂) / 2, in other words, the acceleration is calculated from the speed change between the reference point Xr and the sensor middle point. In addition, under the assumption that the acceleration is constant, the acceleration can be detected based on the speed change between any two points.
[0065]
As can be seen from the above description, the reference time tr and the reference speed Vr are obtained from the string striking time and the string striking speed in the performance data, and further, the key-on speed Vk and the key-on time tk are obtained.₂, The acceleration a is obtained.
Therefore, if the key press start time and the initial velocity are obtained, the key can be driven along the parabolic trajectory shown in FIG. Next, how to obtain these will be described.
First, as shown in FIG.₀, The initial speed is V₀Then, the coefficient b in Equation 11 is
[0066]
[Equation 14]
b = V₀-At₀
And the constant c in Equation 11 is
[0067]
(Equation 15)
c = X₀− (A / 2) · t₀ ²+ Bt₀
(Where X in Equation 15 is₀Is the rest position as described above).
Here, the reference time when the key depressing start time is set as a reference (= 0) is tr ′, and the equation 11 is rewritten into the equation at the reference point Xr using the equations 14 and 15, and the following equation is obtained. .
[0068]
(Equation 16)
Xr = (a / 2) · tr ′²+ V₀・ Tr '+ X₀
Here, the reference speed Vr is
[0069]
[Equation 17]
Vr = a · tr ′ + V₀
Substituting this relationship into Equation 16 and rearranging it gives:
[0070]
(Equation 18)
0 = (a / 2) · tr²−Vr · tr ′-(X₀-Xr)
From here, when tr 'is obtained,
[0071]
[Equation 19]
tr ′ = (Vr− (Vr²+ 2a (X₀-Xr))^1/2) / A
It becomes. Therefore, the acceleration a, the reference speed Vr, the reference point Xr, and the rest position X₀Is known, the time tr 'from the start of key depression to the reference point Xr is obtained. The reference time tr and the key press start time t₀The relationship is
[0072]
(Equation 20)
tr '= tr-t₀
Therefore, the key pressing start time t is calculated by using Equation 20.₀Is required.
Also, by substituting equation 17 into equation 16, the initial velocity V₀If you sort out and solve
[0073]
(Equation 21)
V₀= (Vr²+ 2a (X₀-Xr))^1/2
And the initial speed V₀Can be requested.
Therefore, the initial speed V obtained as described above₀, Acceleration a into Equation 11 to determine the trajectory, and key press start time t₀By driving the key according to the trajectory from the, the string striking time and the string striking speed can be accurately reproduced. Moreover, since it is a parabolic trajectory similar to a human key operation, it is possible to express even a subtle nuance of a player.
Note that time t₀From initial velocity V₀The same effect as described above can be obtained even if the key is driven by and the speed control is performed using the speed change corresponding to the acceleration a.
[0074]
(2) Creation of orbit data at key release
Since a linear trajectory is assumed for key release, key release trajectory data creation similar to that of the above-described second embodiment is performed.
[0075]
(3) Creating orbit data at the time of intersection
Since the intersection between the key press trajectory and the key release trajectory in this embodiment is the intersection between the parabolic trajectory and the linear trajectory, the intersection time tc can be obtained as follows.
[0076]
(Equation 22)
tc = (− Δb + (Δb²-2 · Δa · Δc)^1/2) / Δa
Where Δa in Equation 22 is
[0077]
(Equation 23)
Δa = a−aN
Where aN is the acceleration at key release. In the case of this embodiment, since the acceleration when the key is released is 0, Δa = a (the acceleration when the key is pressed).
Δb in Equation 22 is
[0078]
[Equation 24]

Where Δc is
[0079]
(Equation 25)

It is.
In this way, the intersection time tc is obtained, and the trajectory data at the time of intersection is created by combining the key press trajectory and the key release trajectory.
[0080]
The above is the trajectory data creation processing of the pre-playback processing unit 10 in the third embodiment. The trajectory data created in this way is supplied to the motion controller 11 shown in FIG. 6, where the motion controller 11 generates position control data corresponding to the position of the key 1 at each time based on the created trajectory data. (X) is created and supplied to the servo controller 12. The configurations of the motion controller 11 and the servo controller 12 are the same as in the second embodiment.
[0081]
(B) Operation of the third embodiment
Next, the operation of the third embodiment will be described. However, since the operation is substantially the same as that of the second embodiment, only different points will be described.
First, in the recording operation, the performance recording unit 30 also detects the key-on time and the key-on speed based on the output signal of the sensor 25 and normalizes the key-on time and the key-on speed in the recording post-processing unit 31. And the like.
[0082]
Next, the reproduction operation will be described. First, the reproduction pre-processing unit 10 reads the performance information from the recording medium, and based on the stringing time data, the stringing speed data, the key-on speed data, and the key-on time data therein. Create a parabolic key depression trajectory. The created parabolic key depression trajectory data is supplied to the motion controller 11, where it is converted into position control data (X). That is, the key press start time t₀Then, the trajectory data shown in Expression 11 is supplied to the motion controller 11, and the motion controller 11 sequentially calculates X in Expression 11 with the passage of time to create position control data (X). The position control data (X) is supplied to the servo controller 12, whereby the exciting current corresponding to X in Expression 3 is supplied to the solenoid 5. In this case, the servo controller 12 compares the feedback signal of the solenoid 5 with the position control data (X) and controls the exciting current so that the two coincide with each other. It corresponds to X. Therefore, the key 1 is depressed according to the parabolic trajectory shown in Expression 11, andReAt the reference point XrReA motion having a reference speed Vr and an acceleration a is performed. As a result, string striking that faithfully reproduces the string striking strength during recording is performed. Moreover, since the acceleration is also reproduced by the parabolic trajectory close to the state of the human performance, the subtle nuance of the performance is also reproduced. When the key depression trajectory intersects with the key release trajectory, the pre-playback processing unit 10 calculates the intersection time tc according to equation 21, and switches the key depression trajectory and the key release trajectory from this time to the motion controller 11. To supply. As a result, the key 1 is switched to a linear key release trajectory from the middle of the parabolic key release trajectory, or to a parabolic key release trajectory from the middle of the linear key release trajectory. Do.
[0083]
Here, FIG. 12 shows an experimental example in the case where the key is driven according to the present embodiment. In each of the three graphs shown in FIG. 12, the horizontal axis represents time, and the vertical axis represents the key rest position X.₀It shows the amount of movement from.
(A) shown in this figure shows the trajectory of the key when the performer actually performed, and the time t shown in the figure.₁₀, T₁₁Key is in the rest position X for half-stroke playing₀Before returning to, the next key pressing operation is started. Time t₁₂The vicinity is where the keys are moving but no strings are struck.
Also, based on the stringing time, stringing speed, key-on time, key-on speed, key-release time and key-release speed obtained from the performance shown in FIG. The key trajectory is the trajectory shown in FIG. Also, FIG. 2B shows the two orbits shown in FIGS. 1A and 1C overlapped, and it can be seen that the two orbits match well. For example, for the half-stroke portion, the reproduction trajectory is also a half-stroke trajectory, and the time t when the string is not struck is obtained.₁₂As for the part, the key has been fully depressed in the reproduction trajectory.
[0084]
FIG. 13 is an enlarged view of a part of FIG. 12, and it is confirmed from this figure that the key trajectory obtained by the actual performance matches the key trajectory reproduced in the embodiment. Although the key trajectory reproduced in the embodiment has little fluctuation with respect to the key trajectory of the actual performance, it looks simple at first glance, but the fluctuation included in the trajectory shown in FIG. 12A is different from the intention of the player. Most of the parts (parts due to mistakes or parts not related to the performance caused by the action mechanism characteristics). Therefore, it can be said that the trajectory according to the embodiment is a trajectory closer to the ideal, excluding a part different from the intention of the player.
[0085]
(C) Modification of the third embodiment
(1) Reproduction of damper string release timing
It is well known that when the key is pressed, first, the damper 6 (see FIG. 6) separates from the string, and then the hammer 2 strikes the string. In this case, even if the damper 6 is separated from the string, no sound is generated until the string is struck, so there is a thought that it is meaningless to accurately reproduce the string separation of the damper 6. However, when multiple keys are pressed at the same time or close to each other, for example, due to the vibration or resonance of other strings, if the damper is separated even before the string is struck, May vibrate. Therefore, it can be said that it is also important to accurately reproduce the string release timing of the damper in order to faithfully reproduce the influence of other strings in the performance.
Therefore, the damper separation timing is estimated as follows. First, as described above, the key-on time is set to tk.₂And the key-on speed is Vk, and the key-on position (the position of the key when the shutter 26 provided on the key 1 shields the lower photosensor in the key sensor 25 from light) is Xk.₂And Next, as shown in FIG. 14, the key position corresponding to the string separation of the damper is set to X.₁And a straight line is drawn along the slope of the key-on speed Vk. And this straight line and the position X₁The time of the intersection with the damper stringing time t₁It is estimated. That is, the damper separation time t₁Is obtained by the following equation.
[0086]
(Equation 26)
t₁= Tk₂− (Xk₂-X₁) / Vk
As described above, the damper separation time t₁Is obtained, the reference speed Vr and the reference time tr are obtained in the same manner as in the above-described embodiments, and a parabolic trajectory satisfying these is obtained. This parabolic trajectory is shown in FIG. This trajectory is expressed as follows.
[0087]
[Equation 27]
X = (((X₁−Xr) −Vr · (t₁-Tr)) / (t₁-Tr)²) ・ T²+ Vr · t
Therefore, if the exciting current of the solenoid is controlled in accordance with the trajectory shown in Expression 27, the damper separation time can be accurately reproduced. The control of the excitation current may be performed in the same manner as in the above-described embodiments.
[0088]
(2) Fixed acceleration and initial speed
In the third embodiment, the acceleration a at the time of key depression and the initial velocity V₀Are calculated by calculation, but one of them may be fixed to simplify the calculation. The fixed value in this case is desirably determined statistically by repeating experiments and the like.
For example, accelerationaIs fixed, a = 2.5 m / s², It was found that relatively good results could be obtained. Here, a = 2.5 m / s²FIG. 16 shows the experimental results in the case of.
[0089]
(A) shown in this figure shows the trajectory of the key when the player actually performed, and (C) shows the string striking time and string striking speed obtained from the performance shown in FIG. And a key depression trajectory reproduced with the acceleration fixed. That is, the value of the acceleration a in the trajectory shown in Equation 11 is fixed, and the key-depression trajectory is obtained by omitting the acceleration calculation shown in Equation 12. Since the key release trajectory is a straight trajectory, it is the same as in the above-described embodiment.
Also, FIG. 2B shows the two orbits shown in FIGS. 1A and 1C overlapped, and it can be seen that the two orbits match well. For example, good consistency is also observed for the half-stroke portion. 17 (a), (b) and (c) are partially enlarged trajectories of FIGS. 16 (a), (b) and (c).
When the acceleration is fixed as described above, the calculation can be omitted, so that the processing speed is increased and the detection of the key-on speed Vk and the key-on time tk2 becomes unnecessary, so that the apparatus configuration is the same as that of the second embodiment. Can also be implemented.
[0090]
Next, the initial speed V₀Is fixed. In this case, the calculation of Equation 20 is omitted, and the preset initial speed V₀May be used to calculate the trajectory shown in Equation 11.
Here, the initial speed V₀FIG. 18 shows the experimental results in the case where is set to 0.1 m / s.
(A) shown in this figure shows the trajectory of the key when the player actually performed, and (C) shows the string striking time and string striking speed obtained from the performance shown in FIG. And the initial speed V₀Shows the key depression trajectory reproduced by fixing. In other words, the initial velocity calculation of the above-described equation 20 is omitted, and the initial velocity V₀Is fixed, and the key press trajectory shown in Expression 11 is obtained under this condition. Since the key release trajectory is a straight trajectory, it is the same as in the above-described embodiment. FIG. 2 (b) shows the two orbits shown in FIGS. 1 (a) and 1 (c) which are superimposed, and it can be seen that they are well matched. 19 (a), (b) and (c) are partially enlarged trajectories of FIGS. 18 (a), (b) and (c).
[0091]
D: Modified example
In the present invention, various modifications described below can be made to the above-described embodiments.
(1) Deformation of servo control
In each of the above-described embodiments, the position servo control is performed by the motion controller 11 and the servo controller 12. However, in the second embodiment, the speed servo control for instructing the speed may be performed instead. That is, the motion controller 11 may instruct the initial speed at the time of the key press (or key release) disclosure time, and the servo controller 12 may perform the servo control so that the key 1 keeps the given speed. In the third embodiment, acceleration control may be performed. That is, the motion controller 11 specifies the initial speed at the key pressing start time, and thereafter sequentially instructs a change in the speed as time elapses. Then, the servo controller 12 accumulates the change in speed, calculates the current speed, and performs servo control so that the speed of the key 1 matches the accumulated speed.
[0092]
(2) Application of estimated acceleration information to electronic musical instruments
The acceleration a estimated in the third embodiment can be used not only for the key depression control of the automatic piano but also for the tone control of an electronic musical instrument or the like. That is, the acceleration can be estimated if there is at least one key pressing speed information and one or more string striking speed information. Therefore, the acceleration can be estimated based on these information and can be used as the musical tone control information. For example, there is an electronic musical instrument that stores a plurality of musical sound waveforms and selects and reads out these waveforms according to the intensity and height of the sound. If this electronic musical instrument is further made to perform waveform selection according to acceleration information, This has the advantage that the expression of the generated musical tone is further enhanced.
[0093]
Further, in the third embodiment, the acceleration is estimated based on the deviation between the key-on speed Vr and the reference speed Vr, but may be estimated from the difference between the string striking speed and the key-on speed. Also, the stringing speed may be estimated from these speed differences so as to be detected at two or more places. Further, the key pressing speed may be detected at two or more places and detected from these speed differences. Good.
[0094]
Further, the estimation of the acceleration may be performed at the time of recording, at the time of reproduction, or in the middle of these. For example, when performance information is read from a recording medium, the acceleration may be estimated and recorded on another recording medium.
[0095]
(3) Deformation of motion attribute at reference point Xr
In each of the embodiments described above, the speed and acceleration of the key at the reference point Xr are reproduced. However, if the motion of the key can be reproduced uniquely, other motion attributes may be reproduced. . For example, any of speed, acceleration, and force, or a combination thereof may be used.
[0096]
(4) Acceleration trajectory at key release
In each of the embodiments described above, the trajectories at the time of key release are all linear trajectories, but these may be used as acceleration trajectories. In this case, a sensor may be added to measure the key release speed at two or more locations, and the acceleration may be estimated from the obtained change in the speed. For example, the number of photo sensors in the key sensor 25 may be increased, and the performance recording unit 30 may detect two or more key release speeds from output signals of these sensors.
Furthermore, it is possible to arbitrarily combine whether the trajectory at the time of key depression and the key release is a straight line or a parabola.
[0097]
(5) Square root calculation mode
The initial velocity calculation operation (Equation 20) and the key press start time calculation operation (Equations 18 and 19) in the third embodiment include square root extraction, but if the operation speed on software is a problem, for example, two minutes A positive number operation may be performed using a search method.
[0098]
▲ 6 ▼ Reproduction of weak sound
In an actual key pressing operation, the tendency to take a parabolic trajectory is smaller in a weak hit than in a strong hit, and the reproducibility deteriorates in a reproduction in a straight trajectory. In particular, when trying to reproduce a key depressed close to the weakest hit (pppp) in a linear trajectory, the power may not be transmitted to the hammer and the string may be unstable due to the structure of the action portion of the piano. . Therefore, in the second embodiment, only weak sounds may be detected and reproduced on a parabolic trajectory, and other sounds may be reproduced on a straight trajectory. That is, the playback pre-processing unit10In the above, the string striking speed data is sorted by a predetermined threshold value, and for a sound determined to be a weak sound, a parabolic trajectory is calculated using a preset acceleration a, and the key is thereby driven.
[0099]
(7) Substitution of string striking time and string striking speed
For example, in Japanese Unexamined Patent Publication No. 1-239594, the stringing speed is estimated and recorded from the key-pressing speed. In this way, when data replacing the stringing speed is recorded, each of the above-described data is recorded. In embodiments, it is also possible to use it. Therefore, when data corresponding to the string striking speed is recorded, such as the key-on speed (key velocity) in the MIDI signal, the trajectory calculation can be performed using this. The string striking time can also be substituted if there is data alternative to this. In short, any data related to the sounding time and the sounding intensity (sounding time information indicating the sounding time and sounding intensity information indicating the sounding intensity) can be used.
[0100]
【The invention's effect】
As described above, according to the present invention, the key is driven so that the motion attribute at the predetermined point (reference point) of the key trajectory is reproduced, so that the behavior of the hammer can be faithfully reproduced. String speed can be accurate. In addition, if the key is driven along a straight orbit or a parabola orbit passing through the predetermined point, the motion attribute of the key at the predetermined point is surely reproduced.ToIn particular, when a parabolic trajectory is adopted, the nuance of the performance can be reproduced because the trajectory is close to the key operation trajectory of a human.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.
FIG. 2 is a diagram showing a relationship between a key speed and a string striking speed when a reference point is set to 9.5 mm.
FIG. 3 is a diagram showing a relationship between a reference time difference Tr and a string striking speed.
FIG. 4 is a diagram of FIG. 3 on a double scale.
FIG. 5 is a diagram in which FIG. 3 is quadrupled in scale.
FIG. 6 is a block diagram showing a configuration of a second embodiment.
FIG. 7 is a diagram illustrating a key pressing trajectory (linear trajectory) of a key.
FIG. 8 is a diagram illustrating a trajectory represented by Expression 6.
FIG. 9 is a diagram illustrating a case where trajectories of a key release that occurs after a key is pressed intersect.
FIG. 10 is a diagram showing a parabolic trajectory used in the third embodiment.
FIG. 11 is a diagram for explaining calculation of a key pressing start time in a third embodiment.
FIG. 12 is a diagram showing an experimental example when a key is driven in the third embodiment.
FIG. 13 is an enlarged view of a part of FIG.
FIG. 14 is a diagram for explaining a method of estimating a string separation time of a damper.
FIG. 15 is a diagram illustrating a parabolic trajectory in a case where a damper string separation time is reproduced.
FIG. 16 is a diagram showing experimental results when acceleration is fixed in the third embodiment.
FIG. 17 is an enlarged view of a part of FIG. 16;
FIG. 18 is a diagram showing experimental results when the initial speed is fixed in the third embodiment.
FIG. 19 is an enlarged view of a part of FIG. 18;
FIG. 20 is a schematic view showing a configuration of a general automatic piano.
[Explanation of symbols]
5 ... solenoid (key driving means: servo driving means), 10 ... reproduction preprocessing section (motion attribute calculating means: trajectory calculating means: weak sound extracting means), 11 ... motion controller (key driving means: command value outputting means) ), 12... Servo controller (key driving means: servo driving means).

Claims (6)

An automatic piano that rotates a hammer by pressing a key and generates sound by striking a string with the hammer,
Supply means for supplying sounding time information indicating a sounding time as a timing at which the hammer hits a string and sounding intensity information indicating a sounding intensity as a strength at which the hammer hits a string ;
The motion attribute of the key at a predetermined point within a range from the key rest position to the end position, where the key speed and the sounding intensity of the hammer striking a string indicate a specific correspondence. An exercise attribute calculating means for obtaining from the pronunciation intensity indicated by the pronunciation intensity information and the pronunciation time indicated by the pronunciation time information using the correspondence ,
Driving means for driving said key,
An automatic piano, comprising: control means for controlling driving of the key by the driving means so that the key has the motion attribute obtained at the predetermined point . An automatic piano that rotates a hammer by pressing a key and generates sound by striking a string with the hammer,
Supply means for supplying sounding time information indicating a sounding time as a timing at which the hammer hits a string and sounding intensity information indicating a sounding intensity as a strength at which the hammer hits a string ;
The passing speed of the key at a predetermined point within a range from the key rest position to the end position, where the speed and the sounding intensity of the hammer striking the string show a specific correspondence, Exercise attribute calculating means for obtaining from the sounding intensity indicated by the sounding intensity information using the correspondence relationship, and obtaining the key passing time at the predetermined point from the obtained passing speed and the sounding time indicated by the sounding time information ,
A trajectory calculation unit that calculates a key trajectory satisfying the passage speed and the passage time obtained by the motion attribute calculation unit as a relationship of a key position with respect to time, and calculates a key pressing start time in the key trajectory ;
Driving means for driving said key,
The key starts key depression from the determined key depression start time, reaches the predetermined point at the determined passage time, and has a passage speed determined when the key reaches the predetermined point. An automatic piano, comprising: control means for controlling driving of a key by the driving means . An automatic piano in which a key is pressed to produce a sound by striking a string, while a key is released by a damper to suppress the string and mute the sound.
Supply means for supplying key release time information indicating key release time and key release speed information indicating key release speed;
The key is set in advance within a range from the key end position to the rest position, and the key is set at a predetermined point corresponding to the string suppression start point by the damper at the key release time indicated by the key release time information. A trajectory calculating means for calculating a key trajectory passing at a key release speed represented by the following as a relationship of a key position with respect to time, and obtaining a key release start time in the key trajectory ;
Driving means for driving said key,
The key is started to be released from the obtained key release start time, and at the predetermined point, at the key release time indicated by the key release time information, the key release speed is indicated by the key release speed information. And a control means for controlling driving of the key by the driving means . 4. The automatic piano according to claim 2, wherein said trajectory calculating means calculates a parabolic trajectory of a key satisfying a preset acceleration, a passing time and a passing speed obtained by said motion attribute calculating means. 5. The automatic piano according to claim 4, wherein the trajectory calculating means uses a value set in advance for the initial velocity of the key when calculating the parabolic trajectory. Comprising a weak sound extraction means for comparing the pronunciation intensity information and a reference value to extract a weak sound,
The trajectory calculation means calculates a preset acceleration for the extracted weak sound, a parabolic trajectory of a key that satisfies the passage time and the passage speed determined by the movement attribute calculation means, and the movement attribute calculation means for other than the weak sound. 3. The automatic piano according to claim 2, wherein a straight trajectory of a key satisfying the determined passing time and passing speed is calculated.

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