JP3574814B2

JP3574814B2 - Aircraft ultrasonic airspeed sensor

Info

Publication number: JP3574814B2
Application number: JP2000090200A
Authority: JP
Inventors: 浜木井之口
Original assignee: Japan Aerospace Exploration Agency JAXA
Current assignee: Japan Aerospace Exploration Agency JAXA
Priority date: 2000-03-29
Filing date: 2000-03-29
Publication date: 2004-10-06
Anticipated expiration: 2020-03-29
Also published as: JP2001278196A

Description

【０００１】
【発明の属する技術分野】
本発明は、対気速度計測に関するものであり、特に低速航空機に適した対気速度計測に関するものである。対気速度とは物体に対する３次元的な気流の方向および速さを表す。低速航空機とは、短距離離着陸機、垂直離着陸機、回転翼機、飛行船、気球などである。
【０００２】
【従来の技術】
通常、航空機で使用されているピトー管は、空気の総圧及び静圧を測定して、その差の動圧から対気速度を求めるものであって、気流方向は矢羽根等により測定される。ところで、ピトー管で測定される動圧は、対気速度の２乗に比例する関係にあるために、低速では測定誤差が大きくなってしまい、ピトー管は低速域の速度計測には適していない。ピトー管が利用できる速度は通常、３０〜４０ｍ／ｓ以上の領域である。それより低速であるとか、気流方向が機体軸線と大きく異なる場合には、速度測定自体が不可能となる。そして、気流方向を測定するための矢羽根は、可動部分があるため矢羽根の質量による応答性の低下や振動が問題となってくる。したがって、対気速度センサとしてピトー管を搭載している一般の航空機は、低速域での対気速度計測値は測定誤差が大きいかあるいは測定が出来ないということになっている。
【０００３】
これに対して気象観測に用いられている超音波風速計は、一定区間を伝搬する超音波の伝搬時間が、風の影響で変化することを利用したもので、全方位的に所定の間隔で配設された複数個（一般には６個）の超音波送受信器は平面上のあらゆる方位の風を測定することが出来る。しかし、超音波送受信機同士の空気力学的干渉により、強風時の測定は困難で、航空機搭載が可能な大きさのものでは２０ｍ／ｓ以下、地上設置用の大型装置でも６０ｍ／ｓ以下が測定可能領域である。この測定可能領域では航空機に利用するには高速側の計測範囲が充分とはいえず、気象観測用の超音波風速計は、航空機に搭載する対気流速計測器には適していない。
【０００４】
【発明が解決しようとする課題】
本発明の目的課題は、上記の問題点を解決するもの、すなわち弱風の測定に適し可動部が存在しない超音波風速計のセンサ・ブローブを改良して低速領域の計測が可能である航空機用の対気速度計測装置を提供することにある。
【０００５】
【課題を解決するための手段】
航空機の前方方向に向けその軸芯が三角形の各頂点に位置するように機体に取り付けられた３本の平行な支持棒上に、複数個の超音波送受信機を軸方向に位置を異ならせて配備し、隣接する支持棒上の超音波送受信機との組合せで複数組の超音波送受信経路が形成されるようにし、所定距離の前記複数組の超音波送受信経路を伝搬する時間情報から対気速度に関する３次元情報を得る。
【０００６】
【発明の実施の形態】図１は、超音波風速計の原理を示す図である。超音波が空気中を伝搬する場合、超音波が風と順方向に伝搬するときは、風速分だけ伝搬速度が速くなり、逆方向のときは風速分だけ伝搬速度が遅くなる。したがって、距離を速度で割った関係にある超音波の伝搬時間と風速との関係は以下の式の通りになる。
【数１】

ただし、Ｖ：風速Ｄ：超音波送受信機の間隔
ｔ_１：風速に順方向の超音波の伝搬時間
ｔ_２：風速に逆方向の超音波の伝搬時間
【０００７】
従来、気象観測用の超音波風速計は全方位の風速を等しい精度で検出する必要から、６個の超音波送受信機を６本の支持棒に取りつけていたため形状が複雑となり、空気力学的騒音や気流の乱れによる指示棒の振動が生じやすかった。しかし、一般的に航空機は１方向にのみ高速で飛行し、他の方向は飛行できないか、または非常に低速で飛行する。したがって、航空機用対気速度センサとしては、あらゆる方位の気流が同じように測定できる必要はなく、比較的高速域が測定できるのは１方向のみでよい。したがって、１方向の気流の計測を重視する観点から超音波風速計で必要な６個の超音波送受信機の配列を工夫すると共に、装置の全体形状を単純化し、空気力学的騒音や気流の乱れを低減させることを考えた。特に、超音波送受信機の上流に物体があると、気流の乱れの影響を受けやすいため、１方向の気流を重視して、送受信機の上流に気流の乱れを生じさせる構造物を配置しないようにすることは重要である。
【０００８】
図２と図３を参照して本発明の基本原理を説明する。図２はプローブ形状を示したもので、Ａは前方からの正面図であり、Ｂは側面図である。基部１に３本の支持棒１１、１２、１３を軸が互いに平行で軸芯が三角形の各頂点に位置するように植設し、その先端部は流線形状としている。このプローブ形状は超音波計測の安定性確保の観点から航空機の主たる検出成分となる流速方向が機体前方からの軸方向と一致する気流に対し最も気流に乱れを生じさせないようにすることを考慮して案出したものである。本発明は航空機の対気速度計測に用いるものであるから、前述したように機体に対して流速方向は前方から後方に向かう成分が主となる。したがって、その成分を検出するために超音波送受信機は前後方向に位置を違えた配置を必須とするが、必ずしも別個の支持部材に設置する必要がないことに鑑み、本発明者は気流を乱す原因となる支持部材の数を極力少なくするため同じ支持棒に複数個の超音波送受信機を設置することを考えた。そして超音波送受信する複数組の伝搬経路を形成させて気体の流速成分が重畳される伝搬時間情報を基にその気体の流速成分を３次元情報として計測するものである。具体的には従来の超音波風速計の６個の超音波送受信機を図３に示したような形態、すなわち、プローブの取り付け方向として支持棒１１、１２、１３の軸方向が航空機の前後方向に向くように機体に固定し、この支持棒１１、１２、１３に超音波送受信機１ａ、１ｂ、２ａ、２ｂ、３ａ、３ｂを各支持棒上に軸方向所定距離間隔Ｌをもたせて２個ずつ配備し、隣接する支持棒上の前記超音波送受信機のうち一方が前方配置されたものであるとき他方は後方配置されたものとの組合せで３組（１ａ−２ｂ、２ａ−３ｂ、３ａ−１ｂ）の超音波送受信経路が形成されるようにした。機体の前後方向の異なる位置に配置された超音波送受信機間で超音波送受信経路が形成されているので、機体の前後方向の成分の流速が検知できるのである。しかもこの方向の気流に対してはプローブの支持棒１１、１２、１３が最も抵抗が少ない構造となっているため、流れの状態が安定して精度の良い計測ができる。なお、図３では各支持棒上の２つの超音波送受信機を軸方向同じ距離間隔Ｌで配置したが、原理上は各支持棒とも既知の値であればよく必ずしも同じ間隔にする必要はないのであるが、同じであることは信号処理の演算上簡便で有利である。また各支持棒の軸芯が作る三角形も正三角形であることが対称構造となってやはり信号処理の演算上簡便で有利である。
【０００９】
上記のような機体に対する超音波送受信機の配置構成により、３次元的な対気速度を求めることが出来る。そしてこの配置は矢印で示した方向の流速計測を最も重視したものである。図３のように機体の前後方向にＸ軸を、左右方向にＹ軸をそして上下方向にＺ軸の直交座標系を定義し、対気速度のＸＹＺ成分をＶｘ、Ｖｙ、Ｖｚとすると、計測される各組の超音波送受信機間の超音波伝搬方向の気流の速度成分、すなわち2a-3b間の速度成分Ｗ_１、3a-1b間の速度成分Ｗ_２、1a-2b間の速度成分Ｗ_３は、それぞれ以下の式で表される。
【数２】

ただし、Ｖｘ：対気速度のＸ方向成分
Ｖｙ：対気速度のＹ方向成分
Ｖｚ：対気速度のＺ方向成分
Ｗ_１：気流の超音波送受信機方向（経路１）の速度成分
Ｗ_２：気流の超音波送受信機方向（経路２）の速度成分
Ｗ_３：気流の超音波送受信機方向（経路３）の速度成分
θ_１：ＹＺ面とＷ_１との成す角
θ_２：ＹＺ面とＷ_２との成す角
θ_３：ＹＺ面とＷ_３との成す角
φ_２：ＹＺ面内でのＹ軸とＷ_２との成す角
φ_３：ＹＺ面内でのＹ軸とＷ_３との成す角
ここで仮に各センサの配列を正三角形、つまりφ_２を２４０度、φ_３を１２０度とし、さらにθ_１＝θ_２＝ θ_３＝θ とすると、
【数３】

となり、この演算式によって対気速度を求めることが出来る。
【００１０】
前後配置した２つの超音波送受信機の所定距離間隔Ｌが支持棒１１、１２、１３間の距離Ｄ_０より大きければ、伝搬経路方向に近い流速成分ほど往復の伝搬時間差が大きくなる原理に基づき、対気速度計測において航空機の前方からの流速成分に対し感度がよくなるため、その成分の検出に有利となる。Ｌの値を大きくするということはθの値を大きくすることであるが、その場合超音波送受信機のユニットを大きく傾斜させて支持棒に設置する必要があり、そのことが構造的に気流の乱れを起こす原因になってしまうため好ましくない。実際にはθの値は３０度以下としているため、機体軸に直交する方向の成分の方が検出感度が高いのであるが、反面その方向の気流に対しては支持棒が気流を乱す構造となるため検出結果としてＳ／Ｎ比は低くなってしまう。本発明が対象としている低速航空機に適した対気速度計測には２つの超音波送受信機の所定距離間隔Ｌが支持棒１１、１２、１３間の距離Ｄ_０より小さくても十分に対応できるのである。
【００１１】
【実施例】
以下では、回転翼機における対気速度計測用に製作した例を図４に示し、本実施例について詳述する。一般的な回転翼機では前進方向の対気速度が最大８０ｍ／ｓ程度で、それ以外の方向、例えば上下左右に飛行する場合の速度は極低速である。対気速度４０ｍ／ｓ以上の高速域では、従来のピトー管が充分使用可能なため、本発明と併用、または選択的に利用することが出来る。さて、本実施例は３つの支持棒１１，１２，１３の軸が基体１の軸に対し平行ではなく、図に示されたように等しい若干の開き角をもって取付けられている。これは回転翼機において高速状態すなわち強い気流を受けるのは前方方向に限られるため、それに対して構造的に強い必要があることと、気流を乱す構造的ではあるが、その際の気流の乱れは後流として生じるため超音波伝搬路には影響が少ないことを勘案して想到したものである。ちなみにこの実施例では超音波送受信機２ａ−３ｂ、３ａ−１ｂ、１ａ−２ｂ間の伝搬経路長は５０ｍｍ、θ角は２０度とした。また、使用される超音波の周波数は２００ｋＨ_Ｚである。
【００１２】
図５は、回転翼機に本実施例によるセンサを設置搭載した例を示す。回転翼機は、前進速度が他の方向に卓越して大きくしかもメインロータＲの吹下しという現象を伴う。したがって、対気流計測においてその影響を避けるため、センサＳはメインロータの先端よりも前方に位置するように機体前方方向に一致する長いロッド状の基体１の先端に支持棒１１，１２，１３が取り付けた形態で搭載される。これを用いて回転翼機の最高速度（１４０ｋｔ≒７０ｍ／ｓ）までの使用が確認できた。
【００１３】
以上本発明のセンサを低速航空機に適用し対気速度計測に用いるものとして説明してきたが、本発明によるセンサはこれに限らず、もし低速航空機に慣性計測装置など適宜の計測器が備えられ、それにより対地速度が計測されれば、図５にベクトルで示したように、本発明の検出値である対気速度情報Ｖから対地速度分Ｖ_ｇを減じることにより、低速航空機の飛行位置での風速Ｗを求めることもできる。更に、これを成層圏プラットフォーム用飛行船に適用した場合には、飛行船が風によって受ける力を本発明の航空機用超音波対気速度計によって検出し、それを消去させるような運転制御を実行して飛行船を一定位置にとどめる飛行船制御システムを実現することもできる。
【００１４】
【発明の効果】
以上に説明したように、本発明は、超音波風速計のセンサ・ブローブを前方方向からの気流に対して乱れを生じにくい形状に改良し、かつ複数個の超音波送受信機を基体の前後方向に位置を異ならせて配置する形態で低速航空機に搭載するものであるから、従来のピトー管では不可能であった航空機の低速度領域の対気速度計測が可能となる。本発明を操縦用計器に適用すれば、その結果として低速飛行時の速度表示が従来より高精度となり、航空機の飛行安全性を向上させることができる。また、慣性計測装置など適宜の計測器により対地速度が計測されれば、その位置での風速を割出すことができ、空中の特定位置の風を計測することもできる。更に、これを成層圏プラットフォーム用飛行船に適用した場合には、飛行船を一定位置にとどめるための制御用センサとしても使用することができる。
【図面の簡単な説明】
【図１】一般的な超音波風速計の原理説明図である。
【図２】本発明による対気速度センサプローブの形状であり、Ａは前方からの正面図であり、Ｂは側面図である。
【図３】本発明による対気速度センサでの対気速度測定原理図である。
【図４】本発明による対気速度センサを回転翼機用に具体化した実施例を示す図である。
【図５】本発明による対気速度センサを回転翼機に設置搭載した例を示す図である。
【符号の説明】
Ｗ伝搬速度Ｌ支持棒上の超音波送受信機距離
Ｖ風速Ｄ超音波伝搬距離
Ｃ音速Ｓセンサ・プローブ
１基体１１，１２，１３支持棒
ａ，ｂ，１ａ，１ｂ，２ａ，２ｂ，３ａ，３ｂ超音波送受信機[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to airspeed measurement, and more particularly to airspeed measurement suitable for low-speed aircraft. The airspeed represents the direction and speed of a three-dimensional airflow with respect to an object. Low-speed aircraft include short-range take-off and landing aircraft, vertical take-off and landing aircraft, rotary wing aircraft, airships, and balloons.
[0002]
[Prior art]
Normally, a pitot tube used in an aircraft measures the total pressure and static pressure of air, and determines the airspeed from the dynamic pressure of the difference, and the airflow direction is measured by an arrow blade or the like. . By the way, the dynamic pressure measured by the pitot tube is proportional to the square of the airspeed, so that the measurement error increases at low speeds, and the pitot tube is not suitable for speed measurement in a low speed region. . The speed at which the pitot tube can be used is usually in the range of 30 to 40 m / s or more. If the speed is lower than that, or if the airflow direction is significantly different from the body axis, the speed measurement itself becomes impossible. And since the arrow blade for measuring the airflow direction has a movable part, there is a problem that the response is lowered or the vibration is caused by the mass of the arrow blade. Therefore, in a general aircraft equipped with a pitot tube as an airspeed sensor, the measurement value of the airspeed in a low speed range has a large measurement error or cannot be measured.
[0003]
On the other hand, the ultrasonic anemometer used for weather observations utilizes the fact that the propagation time of ultrasonic waves propagating in a certain section changes under the influence of wind, and at predetermined intervals in all directions. A plurality of (generally six) ultrasonic transmitters / receivers arranged can measure wind in all directions on a plane. However, due to the aerodynamic interference between the ultrasonic transceivers, it is difficult to measure in strong winds. Measurements of 20 m / s or less are required for aircraft that can be mounted on aircraft, and 60 m / s or less for large equipment for ground installation. It is a possible area. In this measurable region, the measurement range on the high-speed side is not sufficient for use in an aircraft, and an ultrasonic anemometer for weather observation is not suitable for an airspeed measuring device mounted on an aircraft.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems, that is, to improve the sensor probe of an ultrasonic anemometer that is suitable for measuring weak winds and has no moving parts, and that it is possible to measure a low-speed region for an aircraft. An object of the present invention is to provide an airspeed measuring device.
[0005]
[Means for Solving the Problems]
A plurality of ultrasonic transceivers are displaced in the axial direction on three parallel support rods attached to the fuselage so that their axes are positioned at the vertices of a triangle in the forward direction of the aircraft. In this case, a plurality of sets of ultrasonic transmission / reception paths are formed in combination with the ultrasonic transmission / reception apparatuses on the adjacent support rods. Obtain three-dimensional information on speed.
[0006]
FIG. 1 is a view showing the principle of an ultrasonic anemometer. When the ultrasonic wave propagates in the air, when the ultrasonic wave propagates in the forward direction with the wind, the propagation speed increases by the wind speed, and when the ultrasonic wave propagates in the reverse direction, the propagation speed decreases by the wind speed. Accordingly, the relationship between the propagation time of the ultrasonic wave and the wind speed, which are obtained by dividing the distance by the speed, is as follows.
(Equation 1)

Here, V: wind speed D: interval between ultrasonic transceivers t ₁ : propagation time of ultrasonic wave in forward direction to wind speed t ₂ : propagation time of ultrasonic wave in reverse direction to wind speed
Conventionally, ultrasonic anemometers for meteorological observation have to detect wind speeds in all directions with equal accuracy. Therefore, six ultrasonic transceivers are mounted on six support rods, which complicates the shape and reduces aerodynamic noise. And vibration of the indicator rod due to turbulence in the airflow was likely to occur. However, aircraft generally fly at high speed in only one direction and cannot fly in other directions, or fly at very low speed. Therefore, as an airspeed sensor for an aircraft, it is not necessary to be able to measure airflows in all directions in the same way, and only a single direction can be measured in a relatively high speed range. Therefore, the arrangement of the six ultrasonic transceivers required for the ultrasonic anemometer from the viewpoint of emphasizing the measurement of airflow in one direction is devised, the overall shape of the device is simplified, and aerodynamic noise and turbulence of the airflow are reduced. Was thought to reduce. In particular, if there is an object upstream of the ultrasonic transceiver, it is likely to be affected by the turbulence of the airflow. Therefore, the airflow in one direction is emphasized, and a structure that causes the turbulence of the airflow should not be arranged upstream of the transceiver. Is important.
[0008]
The basic principle of the present invention will be described with reference to FIGS. FIG. 2 shows a probe shape, in which A is a front view from the front, and B is a side view. Three support rods 11, 12, 13 are planted on the base 1 so that the axes are parallel to each other and the axis is positioned at each vertex of a triangle, and the tip is a streamline shape. In order to ensure the stability of ultrasonic measurement, this probe shape is designed to minimize the turbulence in the airflow, where the direction of flow velocity, which is the main detection component of the aircraft, coincides with the axial direction from the front of the aircraft. It was devised. Since the present invention is used for measuring the airspeed of an aircraft, as described above, the main component of the flow velocity direction from the front to the rear is the main body. Therefore, in order to detect the component, the ultrasonic transceiver is required to be arranged in a different position in the front-back direction, but in view of the fact that it is not necessary to install it on a separate support member, the inventor disturbs the air flow. In order to minimize the number of supporting members causing the problem, it was considered to install a plurality of ultrasonic transceivers on the same supporting rod. Then, a plurality of sets of propagation paths for transmitting and receiving ultrasonic waves are formed, and the flow velocity component of the gas is measured as three-dimensional information based on the propagation time information on which the flow velocity component of the gas is superimposed. Specifically, the six ultrasonic transceivers of the conventional ultrasonic anemometer are configured as shown in FIG. 3, that is, the axial directions of the support rods 11, 12, and 13 are set in the front-rear direction of the aircraft as mounting directions of the probe. And two

ultrasonic transceivers

1a, 1b, 2a, 2b, 3a, and 3b are provided on the support rods 11, 12, and 13 with a predetermined distance L in the axial direction on each of the support rods. When one of the ultrasonic transceivers on the adjacent support rod is arranged forward, the other is combined with the rear arranged ultrasonic transceiver, and three sets (1a-2b, 2a-3b, 3a -1b) The ultrasonic transmission / reception path is formed. Since the ultrasonic transmission / reception path is formed between the ultrasonic transmission / reception devices arranged at different positions in the longitudinal direction of the body, the flow velocity of the component in the longitudinal direction of the body can be detected. Moreover, since the support rods 11, 12, and 13 of the probe have the least resistance to the airflow in this direction, the flow state is stable and accurate measurement can be performed. In FIG. 3, two ultrasonic transceivers on each support rod are arranged at the same distance L in the axial direction. However, in principle, each support rod only needs to have a known value and does not necessarily have to have the same distance. However, the fact that they are the same is convenient and advantageous in terms of computation of signal processing. In addition, the triangle formed by the axis of each support rod is also a regular triangle, which is a symmetrical structure, which is also simple and advantageous in signal processing calculations.
[0009]
The three-dimensional airspeed can be determined by the arrangement of the ultrasonic transceiver with respect to the airframe as described above. This arrangement places the most importance on the measurement of the flow velocity in the direction indicated by the arrow. As shown in FIG. 3, an X-axis is defined in the longitudinal direction of the body, a Y-axis is defined in the left-right direction, and a rectangular coordinate system is defined in the Z-axis in the vertical direction. Velocity component of the air flow in the ultrasonic wave propagation direction between the ultrasonic transceivers of each set, ie, velocity component W ₁ between 2a-3b, velocity component W ₂ between 3a-1b, velocity component W between 1a-2b ₃ is represented by the following equations.
(Equation 2)

Here, Vx: X-direction component of airspeed Vy: Y-direction component of airspeed Vz: Z-direction component of airspeed W ₁ : Speed component of airflow in the direction of the ultrasonic transceiver (path 1) W ₂ : airflow Velocity component W _{3 in} the direction of the ultrasonic transmitter / receiver (path 2): velocity component θ _{1 of the} airflow in the direction of the ultrasonic transmitter / receiver (path 3): angle θ ₂ between the YZ plane and W ₁ : the YZ plane and W ₂ preparative the form angle theta _3: YZ plane and _{W 3} and the formed angle phi _2: angle between the Y axis and _{W 2} in the YZ plane phi _3: angle between the Y axis and the _{W 3} in the YZ plane here if equilateral triangle arrangement of the sensors, i.e. phi ₂ to 240 degrees, phi ₃ was 120 degrees, more and _{_{_{θ 1 = θ 2 = θ 3}}} = θ,
(Equation 3)

Thus, the airspeed can be obtained by this equation.
[0010]
If the predetermined distance interval L of the two ultrasonic transceiver arranged before and after is greater than the distance D ₀ between the support rods 11, 12, 13, based on the principle of transit time enough velocity components reciprocating increases closer to the propagation path direction, In the airspeed measurement, the sensitivity to the flow velocity component from the front of the aircraft is improved, which is advantageous for detecting the component. Increasing the value of L means increasing the value of θ. In this case, it is necessary to install the ultrasonic transceiver unit on the support rod with a large inclination, which structurally reduces the airflow. It is not preferable because it causes disturbance. Actually, since the value of θ is set to 30 degrees or less, the detection sensitivity is higher in the component in the direction perpendicular to the body axis, but on the other hand, the support rod disturbs the air flow in that direction. Therefore, the S / N ratio becomes low as a detection result. Since the present invention is the airspeed measurement suitable for the low-speed aircraft are targeted two predetermined distance interval L of the ultrasonic transceiver can respond sufficiently be less than the distance D ₀ between the support bars 11, 12, 13 is there.
[0011]
【Example】
Hereinafter, an example manufactured for measuring airspeed in a rotary wing aircraft is shown in FIG. 4, and this embodiment will be described in detail. In a general rotary wing aircraft, the maximum airspeed in the forward direction is about 80 m / s, and the speed when flying in other directions, for example, up, down, left, and right is extremely low. In the high-speed range where the airspeed is 40 m / s or more, the conventional pitot tube can be used sufficiently, so that it can be used in combination with the present invention or selectively used. Now, in this embodiment, the axes of the three support rods 11, 12, and 13 are not parallel to the axis of the base 1, but are attached with a slight opening angle as shown in the drawing. This is because in a rotary wing aircraft, high speed conditions, that is, strong airflows are limited only in the forward direction, it is necessary to be structurally strong against it, and although it is structurally disrupting the airflow, the turbulence of the airflow at that time Was considered in consideration of the fact that it occurs as a wake and has little effect on the ultrasonic wave propagation path. Incidentally, in this embodiment, the propagation path length between the ultrasonic transceivers 2a-3b, 3a-1b, and 1a-2b was 50 mm, and the θ angle was 20 degrees. The frequency of the ultrasonic waves used is 200kH _Z.
[0012]
FIG. 5 shows an example in which the sensor according to the present embodiment is installed and mounted on a rotary wing machine. The rotary wing machine has a phenomenon in which the forward speed is remarkably large in another direction and the main rotor R is blown down. Therefore, in order to avoid the influence in the airflow measurement, the sensor S is provided with the support rods 11, 12, and 13 at the tip of the long rod-shaped base body 1 which coincides with the forward direction of the fuselage so as to be located forward of the tip of the main rotor. It is mounted in a mounted form. Using this, the use of the rotary wing aircraft up to the maximum speed (140 kt / 70 m / s) was confirmed.
[0013]
The sensor of the present invention has been described as being used to apply and airspeed measured low speed aircraft, sensor according to the present invention is not limited to this, if appropriate, such as inertial measurement unit to the low-speed aircraft instrument provided above if it is thereby measured is ground speed, as shown by vectors in Fig. 5, by reducing the ground speed component V _g from the detection value airspeed information V of the present invention, in the flight position of the low-speed aircraft Of the wind speed W can be obtained. Further, when this is applied to an airship for a stratospheric platform, the airship is detected by the aircraft ultrasonic airspeed meter according to the present invention, and operation control is performed to eliminate the force. It is also possible to realize an airship control system that keeps a constant position.
[0014]
【The invention's effect】
As described above, the present invention improves the sensor probe of the ultrasonic anemometer to a shape that is less likely to be disturbed by the airflow from the front direction, and the plurality of ultrasonic transceivers are arranged in the front-rear direction of the base. Since it is mounted on a low-speed aircraft in such a form that it is arranged at different positions, it is possible to measure the airspeed in a low-speed region of the aircraft, which was impossible with a conventional pitot tube. If the present invention is applied to a control instrument, as a result, the speed display at low speed flight becomes more accurate than before, and the flight safety of the aircraft can be improved. If the ground speed is measured by an appropriate measuring device such as an inertial measuring device, the wind speed at that position can be determined, and the wind at a specific position in the air can be measured. Further, when this is applied to an airship for a stratospheric platform, it can be used as a control sensor for keeping the airship at a fixed position.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the principle of a general ultrasonic anemometer.
FIG. 2 is a shape of an airspeed sensor probe according to the present invention, wherein A is a front view from the front, and B is a side view.
FIG. 3 is an airspeed measurement principle diagram of the airspeed sensor according to the present invention.
FIG. 4 is a diagram showing an embodiment in which the airspeed sensor according to the present invention is embodied for a rotary wing aircraft.
FIG. 5 is a diagram showing an example in which an airspeed sensor according to the present invention is installed and mounted on a rotary wing aircraft.
[Explanation of symbols]
W Propagation velocity L Distance of ultrasonic transmitter / receiver on support rod V Wind velocity D Ultrasonic propagation distance C Sound velocity S Sensor probe 1 Base 11, 12, 13 Support rods a, b, 1a, 1b, 2a, 2b, 3a, 3b Ultrasonic transceiver

Claims

A plurality of ultrasonic waves are placed on three parallel or equal angled support rods attached to the fuselage so that the axis is located at each vertex of the triangle and the axis is oriented in the longitudinal direction of the aircraft. The transceivers are arranged at different positions in the axial direction on the support rods, and a plurality of sets of ultrasonic transmission / reception paths are formed in combination with the ultrasonic transceivers on the adjacent support rods, as three-dimensional information. Aircraft ultrasonic airspeed sensor that obtains airspeed.

The triangle connecting the axes of the support rods in a plane perpendicular to the front-rear direction of the body is an equilateral triangle, and the ultrasonic transceiver is provided two on each support rod in two planes perpendicular to the axial direction of the support rod. Deployed so that when one of the ultrasonic transceivers on the adjacent support rod is arranged forward, the other is combined with the ultrasonic transceiver arranged rearward to form three sets of ultrasonic transmission and reception paths. The aircraft ultrasonic airspeed sensor according to claim 1.

An aircraft ultrasonic airspeed sensor according to claim 1 or 2, and a ground speed measuring means, wherein the ground air speed information is subtracted from the airspeed information detected by the aircraft ultrasonic airspeed sensor. A system that detects the wind speed at a location.

The airship for a stratospheric platform is equipped with the ultrasonic airspeed sensor for aircraft according to claim 1 or 2, and the force received by the airship due to wind is detected by the ultrasonic airspeed sensor for aircraft, and the airborne airspeed sensor is erased. An airship control system that performs such operation control to keep the airship at a fixed position.