JP2017173216A - Calibration system and calibration method of laser doppler velocimeter - Google Patents
Calibration system and calibration method of laser doppler velocimeter Download PDFInfo
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本発明は、レーザドップラ速度計を校正する技術に関するものである。 The present invention relates to a technique for calibrating a laser Doppler velocimeter.
レーザ光を分岐した二つの光束を、被測定物上の同じ領域に、被測定物の移動方向と垂直な方向に対して成す角が+θ、-θとなる方向から照射すると共に、照射した二つの光束によって被測定物上で生じる散乱光を検出し、散乱光のビート周波数をヘテロダイン検波して、被測定物の移動速度を算出するレーザドップラ速度計が知られている（特許文献１、非特許文献１）。 Irradiate and irradiate two beams of light splitting the laser beam to the same area on the object to be measured from the directions where the angles formed with respect to the direction perpendicular to the moving direction of the object to be measured are + θ and −θ. There is known a laser Doppler velocimeter that detects scattered light generated on an object to be measured by two light beams, calculates a moving speed of the object to be measured by heterodyne detection of the beat frequency of the scattered light (Patent Document 1, Non-patent document 1).
図５ａに、このようなレーザドップラ速度計の構成例を示す。
図示するように、このレーザドップラ速度計は、レーザ光源１０１、ビームスプリッタ１０２、ミラー１０３、対物レンズ１０４、光検出器１０５を備えている。
レーザ光源１０１から出射されたビームは、ビームスプリッタ１０２で第１ビームと第２ビームに分岐され、第２のビームは、さらにミラー１０３で反射される。そして、第１のビームとミラー１０３で反射した第２のビームは、被測定物２００の同じ領域を、２θ異なる方向から照射する。
FIG. 5a shows a configuration example of such a laser Doppler velocimeter.
As shown in the figure, the laser Doppler velocimeter includes a laser light source 101, a beam splitter 102, a mirror 103, an objective lens 104, and a photodetector 105.
The beam emitted from the laser light source 101 is branched into a first beam and a second beam by the beam splitter 102, and the second beam is further reflected by the mirror 103. Then, the first beam and the second beam reflected by the mirror 103 irradiate the same region of the DUT 200 from directions different by 2θ.
そして、被測定物２００で散乱された第１ビームと第２ビームの散乱光が、対物レンズ１０４によって光検出器１０５に集光され、光検出器１０５は集光された散乱光を光電変換した検出信号Doutを出力する。 Then, the scattered light of the first beam and the second beam scattered by the DUT 200 is condensed on the photodetector 105 by the objective lens 104, and the photodetector 105 photoelectrically converts the collected scattered light. Outputs detection signal Dout.
ここで、被測定物２００の照射領域には、第１のビームと第２ビームとの干渉によって、照射方向から見て図５ｂに示すような干渉縞が生成される。そして、干渉縞の間隔ｄは、λをレーザ光源１０１が出射するビームの波長として、
d =λ/2sinθ
によって表される。したがって、この干渉縞の間隔ｄは、レーザ光源１０１の波長と、第１ビームと第２ビームが成す角２θに応じて定まる、レーザドップラ速度計毎に固有の固定値となる。
Here, interference fringes as shown in FIG. 5b are generated in the irradiation region of the DUT 200 as viewed from the irradiation direction due to the interference between the first beam and the second beam. Then, the interference fringe spacing d is λ as the wavelength of the beam emitted from the laser light source 101,
d = λ / 2sinθ
Represented by Therefore, the distance d between the interference fringes is a fixed value specific to each laser Doppler velocimeter, which is determined according to the wavelength of the laser light source 101 and the angle 2θ formed by the first beam and the second beam.
また、この状態で、被測定物２００が速度ｖで移動すると、光検出器１０５に集光された散乱光を光電変換した検出信号Doutには、下式で表される周波数fdのビート信号が表れる。 In this state, when the DUT 200 moves at the speed v, the detection signal Dout obtained by photoelectrically converting the scattered light collected on the photodetector 105 includes a beat signal having a frequency fd expressed by the following equation. appear.
fd = (v×2sinθ）/λ= v/d
したがって、光検出器１０５が出力する検出信号Doutに表れるビート信号の周波数fdを測定することにより、測定した周波数fdとレーザドップラ速度計の固有の干渉縞の間隔ｄとより、
v= fd×d
によって被測定物２００の速度ｖを計測することができる。
fd = (v × 2sinθ) / λ = v / d
Therefore, by measuring the frequency fd of the beat signal appearing in the detection signal Dout output from the photodetector 105, the measured frequency fd and the interval d of the inherent interference fringes of the laser Doppler velocimeter
v = fd × d
Thus, the speed v of the DUT 200 can be measured.
上述のように、レーザドップラ速度計の固有の干渉縞の間隔ｄは、レーザ光源の波長λと、第１ビームと第２ビームが成す角２θに応じて、
d =λ/2sinθ
に従って定まる。
As described above, the inherent interference fringe spacing d of the laser Doppler velocimeter depends on the wavelength λ of the laser light source and the angle 2θ formed by the first beam and the second beam,
d = λ / 2sinθ
It is decided according to.
さて、現実のレーザドップラ速度計は、性能向上のために図５ａに示した構成に、絞りや集光レンズなどの様々な光学部品を付加して構成されることが多い。そして、これらの種々の光学部品の配置や向きに依存して第１ビームと第２ビームが成す角は変化するため、この角度を厳密に設計値通りに実現することは現実的には困難である。また、レーザ光源の波長の設計値からのずれを完全に無くすこともできない。このために、干渉縞の間隔ｄは、厳密に設計値通りの値とならない場合が多く、この場合には、干渉縞の間隔ｄとして、当該間隔ｄの設計値を用いると被測定物の速度ｖを正しく計測できなくなる。 An actual laser Doppler velocimeter is often configured by adding various optical components such as a diaphragm and a condenser lens to the configuration shown in FIG. Since the angle formed by the first beam and the second beam varies depending on the arrangement and orientation of these various optical components, it is practically difficult to realize this angle exactly as designed. is there. Further, it is impossible to completely eliminate the deviation of the wavelength of the laser light source from the design value. For this reason, the distance d between the interference fringes is often not exactly the value as designed. In this case, if the design value of the distance d is used as the distance d between the interference fringes, the speed of the object to be measured v cannot be measured correctly.
したがって、レーザドップラ速度計は、速度ｖを正しく計測できるように校正を行う必要がある。
校正の方法としては、信頼できる速度計を校正器として用い、同じ被測定物の速度を、校正器とレーザドップラ速度計で計測し、校正器で計測した速度Vrefとレーザドップラ速度計で計測した速度vより、
Vref=kvを満たす計数kを補正係数として求め、レーザドップラ速度計において、
v= k×fd×d
によって速度を算出することが考えられる。
Therefore, the laser Doppler velocimeter needs to be calibrated so that the velocity v can be measured correctly.
As a calibration method, a reliable speedometer was used as a calibrator, and the speed of the same object was measured with a calibrator and a laser Doppler velocimeter, and measured with a velocity Vref measured with the calibrator and a laser Doppler velocimeter. From speed v
Obtain a count k satisfying Vref = kv as a correction coefficient, and in the laser Doppler velocimeter,
v = k × fd × d
It is conceivable to calculate the speed by
しかし、このような速度を基準として行う校正法の精度は、校正器の速度計測の精度に限定される。また、被測定物の移動という動的な状態の計測を基準として行うため、種々の誤差が生じ易い。 However, the accuracy of the calibration method performed based on such speed is limited to the accuracy of the speed measurement of the calibrator. In addition, since the measurement is performed based on the dynamic state of movement of the object to be measured, various errors are likely to occur.
そこで、本発明は、より精度よくレーザドップラ速度計を校正することを課題とする。 Accordingly, an object of the present invention is to calibrate a laser Doppler velocimeter with higher accuracy.
前記課題達成のために、本発明は、異なる二方向からレーザ光を測定領域に照射すると共に前記測定領域の散乱光を検出して検出信号として出力するレーザドップラ速度計の校正システムを、定盤と、定盤を一軸方向に移動するステージと、校正するレーザドップラ速度計を、前記定盤の面上に前記測定領域が位置する配置で支持する支持手段と、前記レーザドップラ速度計から出力される前記検出信号に表れるビート信号の周期を計数する計数手段と、前記定盤の前記一軸方向の移動距離を計測する移動距離計測手段と、干渉縞間隔算出手段とを備えたものである。ここで、干渉縞間隔算出手段は、前記ステージを介して前記定盤を前記一軸方向への移動を行い、当該移動を行っている期間中に前記検出信号に表れるビート信号の周期の数を前記計数手段を用いて計数すると共に、前記定盤の当該移動の前後の前記一軸方向の移動距離を前記移動距離計測手段を用いて計測し、計測した移動距離を計数したビート信号の周期の数で除した値を、前記レーザドップラ速度計が前記測定領域に形成する干渉縞の間隔として算出する。 In order to achieve the above object, the present invention provides a calibration system for a laser Doppler velocimeter that irradiates a measurement region with laser light from two different directions and detects scattered light in the measurement region and outputs it as a detection signal. And a stage that moves the surface plate in a uniaxial direction, a laser Doppler velocimeter to be calibrated, and a support means that supports the measurement region positioned on the surface of the surface plate, and an output from the laser Doppler velocimeter. A counting means for counting the period of the beat signal appearing in the detection signal, a moving distance measuring means for measuring the moving distance of the surface plate in the uniaxial direction, and an interference fringe interval calculating means. Here, the interference fringe interval calculation means moves the surface plate in the uniaxial direction via the stage, and calculates the number of beat signal cycles appearing in the detection signal during the movement period. While counting using the counting means, the moving distance in the uniaxial direction before and after the movement of the surface plate is measured using the moving distance measuring means, and the measured moving distance is counted as the number of beat signal cycles. The divided value is calculated as an interval between interference fringes formed in the measurement region by the laser Doppler velocimeter.
ここで、このような校正システムには、前記干渉縞間隔算出手段が算出した干渉縞の間隔に対する、前記校正するレーザドップラ速度計の干渉縞の間隔の設計値の比を補正係数として算出する補正係数算出手段を設けるようにしてもよい。 Here, in such a calibration system, a correction for calculating, as a correction coefficient, the ratio of the design value of the interference fringe interval of the laser Doppler velocimeter to be calibrated to the interference fringe interval calculated by the interference fringe interval calculating means. Coefficient calculation means may be provided.
また、以上の校正システムは、前記移動距離計測手段を、前記定盤の前記一軸方向の位置を計測する位置計測装置と、移動の後に前記位置計測装置が計測した位置と当該移動の前に前記位置計測装置が計測した位置との差を、前記定盤の当該移動の前後の前記一軸方向の移動距離として算定する移動距離算定手段とより構成してもよい。 In the above calibration system, the moving distance measuring means includes a position measuring device that measures the position of the surface plate in the uniaxial direction, a position measured by the position measuring device after movement, and the movement before the movement. You may comprise the moving distance calculation means which calculates the difference with the position which the position measuring device measured as the moving distance of the said uniaxial direction before and behind the said movement of the said surface plate.
以上のように、本発明に係る構成システムは、レーザドップラ速度計の干渉縞の間隔の校正を、移動距離計測手段で計測した定盤の移動量と、計数手段が定盤の移動中に計数したビート信号の周期の数とに基づいて干渉縞の間隔を算出することにより行う。 As described above, the configuration system according to the present invention calibrates the interference fringe interval of the laser Doppler velocimeter by counting the amount of movement of the surface plate measured by the movement distance measuring unit and the counting unit counting while the surface plate is moving. This is done by calculating the interval of interference fringes based on the number of beat signal cycles.
ここで、移動距離計測手段の計測誤差の干渉縞の間隔算出の精度に対する影響は、定盤の移動距離を大きくすることにより低減することができ、計数手段によるビート信号の周期の数の計測の精度は定盤の移動速度を遅くすることにより向上することができる。 Here, the influence of the measurement error of the moving distance measuring means on the accuracy of the interference fringe interval calculation can be reduced by increasing the moving distance of the surface plate, and the counting means can measure the number of beat signal cycles. The accuracy can be improved by slowing the moving speed of the surface plate.
よって、本発明によれば、より精度よく干渉縞の間隔の算出をすることができるようになり、レーザドップラ速度計の校正の精度を向上することができる。
なお、本発明は、併せて、異なる二方向からレーザ光を測定領域に照射すると共に前記測定領域の散乱光を検出して検出信号として出力するレーザドップラ速度計の校正方法として、校正するレーザドップラ速度計を、定盤の面上に前記測定領域が位置するように固定するステップと、前記定盤を一軸方向に移動しつつ、当該移動を行っている期間中に前記検出信号に表れるビート信号の周期の数を計数するステップと、前記レーザドップラ速度計と異なる所定の計測装置を用いて前記定盤の前記移動の前後の前記一軸方向の移動距離を計測するステップと、計測した移動距離を計数したビート信号の周期の数で除した値を、前記レーザドップラ速度計が前記測定領域に形成する干渉縞の間隔として算出するステップとを備えた校正方法も提供する。
Therefore, according to the present invention, the interference fringe interval can be calculated more accurately, and the calibration accuracy of the laser Doppler velocimeter can be improved.
In addition, the present invention also relates to a laser Doppler calibrating method as a method of calibrating a laser Doppler velocimeter that irradiates a measurement region with laser light from two different directions and detects scattered light in the measurement region and outputs it as a detection signal. A step of fixing the speedometer so that the measurement area is positioned on the surface of the surface plate, and a beat signal appearing in the detection signal during the movement while moving the surface plate in one axis direction A step of counting the number of cycles, a step of measuring a moving distance in the uniaxial direction before and after the movement of the surface plate using a predetermined measuring device different from the laser Doppler velocimeter, and a measured moving distance And a step of calculating a value obtained by dividing the counted beat signal by the number of cycles of the beat signal as an interval of interference fringes formed in the measurement region by the laser Doppler velocimeter. To.
以上のように、本発明によれば、より精度よくレーザドップラ速度計を校正することができる。 As described above, according to the present invention, the laser Doppler velocimeter can be calibrated with higher accuracy.
以下、本発明に係るレーザドップラ速度計の校正システムの実施形態について示す。
図１に、校正システムの構成と配置を示す。
ここで、図１ａは側方から見た校正システムの構成と配置を、図１ｂは上方から見た校正システムの構成と配置を表している。
図中に表したようにｘｙｚ方向を定めるものとして、校正システムは、定盤１、定盤１を±ｘ方向に移動可能なＸステージ２、校正対象のレーザドップラ速度計１００を定盤１の上空に支持するスタンド３、レーザ測長器４、定盤１に固定された反射体５、図１ａにおいては図示を省略した校正制御装置６を備えている。
Embodiments of a laser Doppler velocimeter calibration system according to the present invention will be described below.
FIG. 1 shows the configuration and arrangement of the calibration system.
Here, FIG. 1a shows the configuration and arrangement of the calibration system viewed from the side, and FIG. 1b shows the configuration and arrangement of the calibration system viewed from above.
As shown in the figure, assuming that the xyz direction is determined, the calibration system includes a surface plate 1, an X stage 2 that can move the surface plate 1 in the ± x direction, and a laser Doppler velocimeter 100 to be calibrated. A stand 3 supported in the sky, a laser length measuring device 4, a reflector 5 fixed to the surface plate 1, and a calibration control device 6 (not shown in FIG. 1a) are provided.
ここで、本実施形態で校正の対象とするレーザドップラ速度計１００の構成は、上記した図５の構成と同様である。
さて、このような校正システムにおいて、反射体５は反射面が+ｘ方向を向くように定盤１の+ｘ方向側端面に固定されており、レーザ測長器４は、ｘステージからｘ方向側に離れた位置より、反射体５に向けて、レーザ光を-ｘ方向に照射し、反射体５で反射したレーザ光より反射体５のｘ軸に沿った変位Ｌを計測する。
Here, the configuration of the laser Doppler velocimeter 100 to be calibrated in the present embodiment is the same as the configuration of FIG. 5 described above.
In such a calibration system, the reflector 5 is fixed to the + x direction side end surface of the surface plate 1 so that the reflection surface faces the + x direction, and the laser length measuring device 4 moves from the x stage to the x direction. Laser light is irradiated in the −x direction toward the reflector 5 from a position away from the side, and the displacement L along the x-axis of the reflector 5 is measured from the laser light reflected by the reflector 5.
次に、スタンド３は、レーザドップラ速度計１００を、レーザドップラ速度計１００が出射する二つのビーム１１１、１１２が、定盤１の上面の同一の領域を照射し、かつ、二つのビーム１１１、１１２を含む面の法線の方向がｙ方向となり、かつ、２θ方向が異なる二つのビーム１１１、１１２の双方に対してθ角度が異なる方向１１３がｚ方向となるように、定盤１の上空にレーザドップラ速度計１００を支持する。 Next, the stand 3 irradiates the laser Doppler velocimeter 100 with the two beams 111 and 112 emitted from the laser Doppler velocimeter 100 irradiating the same area on the upper surface of the surface plate 1, and the two beams 111, Over the surface plate 1, the direction of the normal of the surface including 112 is the y direction, and the direction 113 having a different θ angle with respect to both the two beams 111 and 112 having different 2θ directions is the z direction. The laser Doppler velocimeter 100 is supported.
ここで、定盤１のローリングやヨーイング等の影響を最小化するために、レーザドップラ速度計１００が出射する二つのビーム１１１、１１２が照射する定盤１の面上の領域と、反射体５と、レーザ測長器４の出射するレーザ光の光軸のｙ方向の位置は、定盤１のｙ方向の中央の位置に一致させる。 Here, in order to minimize the influence of rolling and yawing of the surface plate 1, the region on the surface of the surface plate 1 irradiated by the two beams 111 and 112 emitted from the laser Doppler velocimeter 100, and the reflector 5 The position of the optical axis of the laser beam emitted from the laser length measuring device 4 in the y direction is made to coincide with the center position of the surface plate 1 in the y direction.
次に、図２に、上述した校正制御装置６の構成を示す。
図示するように、校正制御装置６は、ビート信号周期数計数部６１と、補正係数算出制御部６２を備えている。
ビート信号周期数計数部６１は、レーザドップラ速度計１００の光検出器１０５から出力される検出信号Doutに表れるビート信号の周期の数を計数し、補正係数算出制御部６２は、次に示す補正係数算出処理を実行し、レーザドップラ速度計１００をレーザドップラ速度計１００の干渉縞の間隔や、レーザドップラ速度計１００を補正するための補正係数を算出する。
Next, FIG. 2 shows the configuration of the calibration control device 6 described above.
As shown in the figure, the calibration control device 6 includes a beat signal cycle number counting unit 61 and a correction coefficient calculation control unit 62.
The beat signal cycle number counting unit 61 counts the number of beat signal cycles appearing in the detection signal Dout output from the photodetector 105 of the laser Doppler velocimeter 100, and the correction coefficient calculation control unit 62 performs the correction described below. The coefficient calculation process is executed, and the laser Doppler velocimeter 100 calculates the interference fringe interval of the laser Doppler velocimeter 100 and the correction coefficient for correcting the laser Doppler velocimeter 100.
以下、補正係数算出制御部６２が実行する補正係数算出処理について説明する。
図３に、この補正係数算出処理の手順を示す。
図示するように、この処理において、補正係数算出制御部６２は、まず、レーザ測長器４をゼロリセットし（現時点の反射体５の変位を０にセットし）、レーザ測長器４に変位の計測を開始させる（ステップ３０２）。
Hereinafter, the correction coefficient calculation process executed by the correction coefficient calculation control unit 62 will be described.
FIG. 3 shows the procedure of the correction coefficient calculation process.
As shown in the figure, in this processing, the correction coefficient calculation control unit 62 first resets the laser length measuring device 4 to zero (sets the current displacement of the reflector 5 to 0), and then moves the laser length measuring device 4 to the displacement. Is started (step 302).
そして、ビート信号周期数計数部６１に、レーザドップラ速度計１００から出力される検出信号Doutに表れるビート信号の周期の数の計数を開始させる（ステップ３０４）。
次に、Ｘステージ２を制御し、定盤１を-ｘ方向に所定時間移動し、その後、定盤１の移動を停止する（ステップ３０６）。
そして、ビート信号周期数計数部６１の、検出信号Doutに表れるビート信号の周期の数の計数を停止させる（ステップ３０８）。
そして、この時点でレーザ測長器４が計測している反射体５の変位Lを取得する（ステップ３１０）。
また、ビート信号周期数計数部６１が計数したビート信号の周期の数Ｎを取得する（ステップ３１２）。
そして、
N×Dtct_d = L
を満たす、Dtct_d = L/Nを、レーザドップラ速度計１００が出射する二つのビーム１１１、１１２が重複して照射する領域に生じる干渉縞の真の間隔として算出する（ステップ３１４）。
Then, the beat signal cycle number counting unit 61 starts counting the number of cycles of the beat signal appearing in the detection signal Dout output from the laser Doppler velocimeter 100 (step 304).
Next, the X stage 2 is controlled, and the surface plate 1 is moved in the -x direction for a predetermined time, and then the movement of the surface plate 1 is stopped (step 306).
Then, the beat signal cycle number counting unit 61 stops counting the number of beat signal cycles appearing in the detection signal Dout (step 308).
And the displacement L of the reflector 5 which the laser length measuring device 4 is measuring at this time is acquired (step 310).
Also, the number N of beat signal cycles counted by the beat signal cycle number counting unit 61 is acquired (step 312).
And
N x Dtct_d = L
Dtct_d = L / N that satisfies the above condition is calculated as the true interval of interference fringes generated in the region where the two beams 111 and 112 emitted from the laser Doppler velocimeter 100 are irradiated in an overlapping manner (step 314).
ここで、変位Lは、定盤１のｘ方向の移動距離を表し、Ｎは定盤１が移動している間に表れたビート信号の周期の数を表す。
図４に、レーザドップラ速度計１００が出射する二つのビーム１１１、１１２が重複して照射する領域に生じる干渉縞の真の間隔をｄとして、ビート信号の波形（ａ）と、定盤１の移動距離MD（ｂ）との関係を示すように、定盤１の移動速度に関わりなく、定盤１が干渉縞の真の間隔ｄ移動する間に、ビート信号の周期が一つ表れる（ビート信号が一度振動する）。
Here, the displacement L represents the moving distance of the surface plate 1 in the x direction, and N represents the number of beat signal cycles that appear while the surface plate 1 is moving.
FIG. 4 shows the beat signal waveform (a) and the surface plate 1 of the surface plate 1 where d is the true distance between the interference fringes generated in the region irradiated with the two beams 111 and 112 emitted from the laser Doppler velocimeter 100. As shown by the relationship with the movement distance MD (b), one beat signal period appears while the surface plate 1 moves the true distance d of the interference fringe regardless of the moving speed of the surface plate 1 (beats). The signal vibrates once).
したがって、ビート信号の周期の数に真の間隔ｄを乗じた値が定盤１の移動距離となり、この移動距離は、レーザ測長器４で計測した定盤１の変位Lと等しい。
したがって、Ｎ×Dtct_d = L を満たす、Dtct_dとして、ビート信号の周期の数から真の間隔dを求めることができる。
さて、図３に戻り、以上のようにして真の干渉縞の間隔Dtct_dを求めたならば（ステップ３１４）、Dsgn_dを、レーザ光源１０１の波長λと、第１ビームと第２ビームが成す角２θの設計値より、
Dsgn_d =λ/2sinθ
により求めた干渉縞の間隔の設計値として、
K×Dsgn_d = Dtct_d
を満たすK= Dtct_d/ Dsgn_dを、補正係数として算出し（ステップ３１６）、補正係数算出処理を終了する。
Therefore, a value obtained by multiplying the number of beat signal cycles by the true interval d is the moving distance of the surface plate 1, and this moving distance is equal to the displacement L of the surface plate 1 measured by the laser length measuring device 4.
Therefore, the true interval d can be obtained from the number of beat signal cycles as Dtct_d that satisfies N × Dtct_d = L.
Now, returning to FIG. 3, if the true interference fringe spacing Dtct_d is obtained as described above (step 314), Dsgn_d is the angle between the wavelength λ of the laser light source 101, the first beam, and the second beam. From the design value of 2θ
Dsgn_d = λ / 2sinθ
As the design value of the interference fringe spacing obtained by
K × Dsgn_d = Dtct_d
K = Dtct_d / Dsgn_d that satisfies the above is calculated as a correction coefficient (step 316), and the correction coefficient calculation process is terminated.
以上、補正係数算出制御部６２が実行する補正係数算出処理について説明した。
さて、このようにして補正係数算出処理で算出された干渉縞の間隔Dtct_dは、干渉縞の間隔ｄとして、このレーザドップラ速度計１００において以降の速度の計測において利用されるように設定され、これにより当該レーザドップラ速度計１００の校正が完了する。または、このようにして補正係数算出処理で算出された補正係数Ｋが干渉縞の間隔の設計値Dsgn_dと共に、このレーザドップラ速度計１００において以降の速度の計測において利用されるように設定され、これにより当該レーザドップラ速度計１００の校正が完了する。
The correction coefficient calculation process executed by the correction coefficient calculation control unit 62 has been described above.
The interference fringe interval Dtct_d calculated in the correction coefficient calculation process in this way is set as the interference fringe interval d so as to be used in the subsequent speed measurement in the laser Doppler velocimeter 100. Thus, the calibration of the laser Doppler velocimeter 100 is completed. Alternatively, the correction coefficient K calculated in the correction coefficient calculation process in this way is set so as to be used in the subsequent speed measurement in the laser Doppler velocimeter 100 together with the design value Dsgn_d of the interference fringe interval. Thus, the calibration of the laser Doppler velocimeter 100 is completed.
以上、本発明の実施形態について説明した。
ここで、以上の実施形態では、定盤の変位の計測にレーザ測長器４を用いたが、レーザ測長器４に代えて、リニアゲージなどの接触式変位計や、レーザ干渉変位計などの他の変位計測装置を設け、当該変位計測装置によって反射体５または定盤１のｘ方向の変位を測定するようにしてもよい
または、レーザ測長器４に代えて、定盤１のｘ方向の位置を計測する位置計測装置を設け、位置計測装置で計測した定盤１の移動の前後の定盤１のｘ方向の位置の差を、定盤１のｘ方向の変位として測定するようにしてもよい。なお、このような位置計測装置としては、定盤１までのｘ方向の距離を計測する距離計などを用いることができる。
The embodiment of the present invention has been described above.
Here, in the above embodiment, the laser length measuring device 4 is used for measuring the displacement of the surface plate, but instead of the laser length measuring device 4, a contact type displacement meter such as a linear gauge, a laser interference displacement meter, or the like. Another displacement measuring device may be provided, and the displacement measuring device may measure the displacement of the reflector 5 or the surface plate 1 in the x direction. Alternatively, instead of the laser length measuring device 4, the x of the surface plate 1 may be used. A position measuring device for measuring the position of the direction is provided, and the difference in the position of the surface plate 1 in the x direction before and after the movement of the surface plate 1 measured by the position measuring device is measured as the displacement of the surface plate 1 in the x direction. It may be. As such a position measuring apparatus, a distance meter that measures the distance in the x direction to the surface plate 1 can be used.
以上のように本実施形態では、レーザドップラ速度計１００の干渉縞の間隔の校正を、レーザ測長器４を用いて計測した定盤１の移動前後の間の移動量と、ビート信号周期数計数部６１が定盤１の移動中に計数したビート信号の周期の数とに基づいて干渉縞の間隔を算出することにより行う。 As described above, in the present embodiment, the calibration of the interference fringe interval of the laser Doppler velocimeter 100 is performed by using the laser length measuring device 4 and the movement amount before and after the movement of the surface plate 1 and the number of beat signal cycles. This is done by calculating the interference fringe interval based on the number of beat signal cycles counted by the counting unit 61 while the surface plate 1 is moving.
ここで、レーザ測長器４の距離計測の誤差の干渉縞の間隔算出の精度に対する影響は、定盤１の移動距離を大きくすることにより低減することができ、ビート信号周期数計数部６１によるビート信号の周期の数の計測の精度は定盤１の移動速度を遅くすることにより向上することができる。 Here, the influence of the distance measurement error of the laser length measuring device 4 on the accuracy of the interference fringe interval calculation can be reduced by increasing the moving distance of the surface plate 1. The accuracy of measurement of the number of beat signal cycles can be improved by slowing the moving speed of the surface plate 1.
よって、本実施形態によれば、より精度よく干渉縞の間隔の算出することができるようになり、これにより、レーザドップラ速度計１００の校正の精度を向上することができる。 Therefore, according to the present embodiment, the interference fringe interval can be calculated with higher accuracy, and thereby the accuracy of calibration of the laser Doppler velocimeter 100 can be improved.
１…定盤、２…Ｘステージ、３…スタンド、４…レーザ測長器、５…反射体、６…校正制御装置、６１…ビート信号周期数計数部、６２…補正係数算出制御部、１００…レーザドップラ速度計、１０１…レーザ光源、１０２…ビームスプリッタ、１０３…ミラー、１０４…対物レンズ、１０５…光検出器。 DESCRIPTION OF SYMBOLS 1 ... Surface plate, 2 ... X stage, 3 ... Stand, 4 ... Laser length measuring device, 5 ... Reflector, 6 ... Calibration control apparatus, 61 ... Beat signal cycle number counting part, 62 ... Correction coefficient calculation control part, 100 DESCRIPTION OF SYMBOLS ... Laser Doppler velocimeter, 101 ... Laser light source, 102 ... Beam splitter, 103 ... Mirror, 104 ... Objective lens, 105 ... Photodetector.
Claims (4)
定盤と、
定盤を一軸方向に移動するステージと、
校正するレーザドップラ速度計を、前記定盤の面上に前記測定領域が位置する配置で支持する支持手段と、
前記レーザドップラ速度計から出力される前記検出信号に表れるビート信号の周期を計数する計数手段と、
前記定盤の前記一軸方向の移動距離を計測する移動距離計測手段と、
干渉縞間隔算出手段とを備え、
前記干渉縞間隔算出手段は、前記ステージを介して前記定盤を前記一軸方向への移動を行い、当該移動を行っている期間中に前記検出信号に表れるビート信号の周期の数を前記計数手段を用いて計数すると共に、前記定盤の当該移動の前後の前記一軸方向の移動距離を前記移動距離計測手段を用いて計測し、計測した移動距離を計数したビート信号の周期の数で除した値を、前記レーザドップラ速度計が前記測定領域に形成する干渉縞の間隔として算出することを特徴とする校正システム。 A laser Doppler velocimeter calibration system for irradiating a measurement region with laser light from two different directions and detecting scattered light in the measurement region and outputting it as a detection signal
A surface plate,
A stage that moves the surface plate in one axis direction;
Support means for supporting a laser Doppler velocimeter to be calibrated in an arrangement in which the measurement region is positioned on the surface of the surface plate;
Counting means for counting the period of the beat signal appearing in the detection signal output from the laser Doppler velocimeter;
A moving distance measuring means for measuring a moving distance in the uniaxial direction of the surface plate;
Interference fringe interval calculation means,
The interference fringe interval calculation means moves the surface plate in the uniaxial direction via the stage, and counts the number of beat signal cycles appearing in the detection signal during the movement period. The movement distance in the uniaxial direction before and after the movement of the surface plate is measured using the movement distance measuring means, and the measured movement distance is divided by the number of beat signal cycles counted. A calibration system, wherein the value is calculated as an interval between interference fringes formed in the measurement region by the laser Doppler velocimeter.
前記干渉縞間隔算出手段が算出した干渉縞の間隔に対する、前記校正するレーザドップラ速度計の干渉縞の間隔の設計値の比を補正係数として算出する補正係数算出手段を有することを特徴とする校正システム。 The calibration system according to claim 1,
Calibration coefficient comprising a correction coefficient calculation means for calculating, as a correction coefficient, a ratio of a design value of the interference fringe distance of the laser Doppler velocimeter to be calibrated to the interference fringe distance calculated by the interference fringe distance calculation means. system.
前記移動距離計測手段は、
前記定盤までの前記一軸方向の位置を計測する位置計測装置と、
移動の後に前記位置計測装置が計測した位置と当該移動の前に前記位置計測装置が計測した位置との差を、前記定盤の当該移動の前後の前記一軸方向の移動距離として算定する移動距離算定手段とを有することを特徴とする校正システム。 The calibration system according to claim 1 or 2,
The moving distance measuring means is
A position measuring device for measuring the position in the uniaxial direction to the surface plate;
A movement distance for calculating the difference between the position measured by the position measurement device after movement and the position measured by the position measurement device before the movement as the movement distance in the uniaxial direction before and after the movement of the surface plate A calibration system comprising a calculation means.
校正するレーザドップラ速度計を、定盤の面上に前記測定領域が位置するように固定するステップと、
前記定盤を一軸方向に移動しつつ、当該移動を行っている期間中に前記検出信号に表れるビート信号の周期の数を計数するステップと、
前記レーザドップラ速度計と異なる所定の計測装置を用いて前記定盤の前記移動の前後の前記一軸方向の移動距離を計測するステップと、
計測した移動距離を計数したビート信号の周期の数で除した値を、前記レーザドップラ速度計が前記測定領域に形成する干渉縞の間隔として算出するステップとを有することを特徴とする校正方法。 A method for calibrating a laser Doppler velocimeter that irradiates a measurement region with laser light from two different directions and detects scattered light in the measurement region and outputs it as a detection signal,
Fixing a laser Doppler velocimeter to be calibrated so that the measurement region is positioned on the surface of the surface plate;
Counting the number of beat signal cycles appearing in the detection signal during the movement while moving the surface plate in a uniaxial direction;
Measuring the movement distance in the uniaxial direction before and after the movement of the surface plate using a predetermined measuring device different from the laser Doppler velocimeter;
And a step of calculating a value obtained by dividing the measured moving distance by the number of beat signal cycles counted as an interval of interference fringes formed in the measurement region by the laser Doppler velocimeter.
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| CN113340560A (en) * | 2021-07-05 | 2021-09-03 | 中国空气动力研究与发展中心低速空气动力研究所 | Doppler interferometer calibration and debugging system, calibration method and debugging method |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0545128A (en) * | 1991-08-15 | 1993-02-23 | Kawasaki Steel Corp | Method for measuring length of moving object |
| JPH0528933U (en) * | 1991-09-27 | 1993-04-16 | 住友金属工業株式会社 | Laser Doppler instrument calibration equipment |
| JPH0611311A (en) * | 1992-06-25 | 1994-01-21 | Sumitomo Metal Ind Ltd | Instrument for measuring length of hot-rolled steel |
| JPH08304452A (en) * | 1995-05-12 | 1996-11-22 | Sumitomo Metal Ind Ltd | Calibration method of laser doppler-type speedometer |
| JPH09113526A (en) * | 1995-10-13 | 1997-05-02 | Nippon Steel Corp | Calibrating device for plate speed detector |
| WO2012069031A1 (en) * | 2010-11-23 | 2012-05-31 | Technische Universität Dresden | Arrangement and method for determining interference fringe distances in order to calibrate laser doppler velocimeters for optical velocity measurements |
| JP2015021914A (en) * | 2013-07-23 | 2015-02-02 | アズビル株式会社 | Speed measuring apparatus and speed measuring method |
-
2016
- 2016-03-25 JP JP2016061461A patent/JP6393289B2/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0545128A (en) * | 1991-08-15 | 1993-02-23 | Kawasaki Steel Corp | Method for measuring length of moving object |
| JPH0528933U (en) * | 1991-09-27 | 1993-04-16 | 住友金属工業株式会社 | Laser Doppler instrument calibration equipment |
| JPH0611311A (en) * | 1992-06-25 | 1994-01-21 | Sumitomo Metal Ind Ltd | Instrument for measuring length of hot-rolled steel |
| JPH08304452A (en) * | 1995-05-12 | 1996-11-22 | Sumitomo Metal Ind Ltd | Calibration method of laser doppler-type speedometer |
| JPH09113526A (en) * | 1995-10-13 | 1997-05-02 | Nippon Steel Corp | Calibrating device for plate speed detector |
| WO2012069031A1 (en) * | 2010-11-23 | 2012-05-31 | Technische Universität Dresden | Arrangement and method for determining interference fringe distances in order to calibrate laser doppler velocimeters for optical velocity measurements |
| JP2015021914A (en) * | 2013-07-23 | 2015-02-02 | アズビル株式会社 | Speed measuring apparatus and speed measuring method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113340560A (en) * | 2021-07-05 | 2021-09-03 | 中国空气动力研究与发展中心低速空气动力研究所 | Doppler interferometer calibration and debugging system, calibration method and debugging method |
| CN113340560B (en) * | 2021-07-05 | 2022-05-17 | 中国空气动力研究与发展中心低速空气动力研究所 | Doppler interferometer calibration and debugging system, calibration method and debugging method |
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