A large-range laser tracking control method based on distance adaptation

Abstract

The application discloses a kind of wide-range laser tracking control methods based on distance adaptation.The method comprises the following steps: constructing a distance adaptive tracking control model;tracking control parameter calibration is carried out on the laser tracking control system, and a calibration dataset is obtained; a least squares objective function is established, the calibration dataset is input, and the coefficients of each order of polynomial are obtained; the current tracking distance and the coefficients of each order of polynomial are input into the distance adaptive tracking control model, and the matched tracking control parameters are output; a motor speed model is established, the tracking control parameters are input, and the motor speed is output; the distance adaptive wide-range laser real-time tracking control of motor speed is carried out using the spot offset compensation tracking control strategy based on distance adaptation.The application makes there be matched tracking control parameters at any distance within the calibration range, reduces the influence of the mismatch between measurement distance and tracking control parameters on long-distance tracking, and improves the stability of wide-range tracking measurement of laser tracker.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser tracking control method, relates to the field of laser tracking interferometry technology and instruments, and particularly relates to a long-range laser tracking control method based on distance adaptation. BACKGROUND

[0002] As a general large-scale space geometric quantity precision measurement instrument, the laser tracker has a wide application in the fields of aerospace, energy machinery, rail transportation, automobile electronics and other large equipment manufacturing due to its high measurement accuracy, wide measurement range, portability and convenience.

[0003] In the laser tracker, a position sensitive detector (PSD) is usually used to detect the offset of the return light spot relative to the target mirror, and the offset is used to control the rotation of the yaw and pitch motors by a certain angle until the measurement beam is aligned with the center of the target mirror. For the same offset, the motor needs to complete tracking at different angles when the target mirror is at different distances, and the farther the distance, the greater the influence of the distance factor on the control system. Therefore, when the laser tracker is in long-range tracking control, the influence of the distance factor should be considered to maintain the tracking stability of the control system. The existing laser tracking control method introduces a coefficient that is linear or piecewise linear with the distance to control the motor speed to compensate for the offset of the light spot, and realizes precise laser tracking within a range of several meters. For tracking distances of tens of meters, there is currently no distance adaptive tracking control method. Therefore, accurately calibrating the tracking control parameters of the motor speed at different distances and accurately matching them with the distance are crucial for precise tracking of long-distance dynamic targets. SUMMARY

[0004] To solve the problems in the background art, the present application provides a long-range laser tracking control method based on distance adaptation. The method calibrates the tracking control parameters of the motor speed of the target ball at different distances, uses the least squares method to construct a relationship model between the tracking control parameters and the distance, and obtains tracking control parameters matched with any distance within the calibration distance range, thereby solving the problem of accurate matching between the measurement distance and the tracking control parameters in long-distance target tracking measurement, improving the long-distance target tracking stability, and realizing precise tracking of long-range space targets.

[0005] The technical solution adopted by the present application is as follows:

[0006] The long-range laser tracking control method based on distance adaptation of the present application comprises:

[0007] 1) Establish a distance adaptive tracking control model of the laser tracking control system.

[0008] 2) calibrate the tracking control parameters of the laser tracking control system, and obtain a calibration data set.

[0009] 3) establish a least square objective function of the laser tracking control system, input the calibration data set into the least square objective function, calculate and obtain the coefficients of each order of the polynomial, input the coefficients of each order of the polynomial and the current tracking distance value at the to-be-measured position into the distance adaptive tracking control model, and the distance adaptive tracking control model outputs matched tracking control parameters.

[0010] 4) establish a motor speed model of the laser tracking control system, input the tracking control parameters into the motor speed model, and the motor speed model outputs the motor speed.

[0011] 5) according to the motor speed in step 4), use the distance adaptive spot offset compensation tracking control strategy to control the motor speed of the laser tracking control system in real time, and finally complete the distance adaptive large-range laser tracking control.

[0012] In the step 1), the distance adaptive tracking control model is specifically as follows:

[0013] k x (l)=a x0 +a x1 l+a x2 l 2 +···+a xm l m

[0014] k y (l)=a y0 +a y1 l+a y2 l 2 +···+a ym l m

[0015] Wherein, k x (l) and k y (l) are the tracking control parameters in the x and y directions at the to-be-measured position, l is the distance between the to-be-measured position and the laser tracking control system, that is, the current tracking distance value at the to-be-measured position; α x0 , α x1 … α xm are the 0, 1…m order coefficients in the x direction, and α y0 , α y1 … α ym are the 0, 1…m order coefficients in the y direction.

[0016] The step 2) is to calibrate the tracking control parameters of the laser tracking control system. First, the center of the target mirror in the laser tracking control system is aligned with the outgoing light of the laser tracking control system. Then, n sampling points are selected at equal intervals within the preset calibration distance range of the laser tracking control system. The target mirror is installed on the circular trajectory generator and placed at each sampling point. The circular trajectory generator drives the target mirror to rotate at a preset tracking speed. The tracking control calibration parameters of the target mirror at each sampling point are obtained. The calibration data set of the laser tracking control system is constructed according to the distance positions of the sampling points and the tracking control calibration parameters.

[0017] The tracking range of the laser tracking control system includes an angle range and a distance range. The tracking speed is the linear rotational speed.

[0018] In the step 3), the least squares objective function is as follows:

[0019]

[0020]

[0021] wherein F x (a) and F y (a) are the least squares objective functions based on the polynomial coefficients a of each order in the x and y directions, respectively; n is the number of sampling points; α x0 , α x1 … α xm are the 0, 1 … m order coefficients in the x direction, respectively; α y0 , α y1 … α ym are the 0, 1 … m order coefficients in the y direction, respectively; l i is the distance between the i-th sampling point position and the laser tracking control system, i = 1, 2, …, n; k x ′(l i ) and k y ′(l i ) are the calibration tracking control parameters of the i-th sampling point position in the x and y directions, respectively.

[0022] The calibration data set includes the distance l i between the i-th sampling point position and the laser tracking control system, and the calibration tracking control parameters of the i-th sampling point position in the x and y directions.

[0023] The least squares objective function is solved using the least squares method to obtain the polynomial coefficients a including the 0, 1 … m order coefficients in the x and y directions. The polynomial coefficients are brought into the distance adaptive tracking control model to obtain the final distance adaptive tracking control model.

[0024] During control, the target mirror is placed at the position to be measured, and the position to be measured is within the calibrated distance range.

[0025] According to the principle of least squares, for each l i The fitted value k is calculated using an m-th degree polynomial. x (l i ) and calibration value k x ′(l i The sum of squares of the residuals between the two should be minimized, and the fitted value k y (l i ) and calibration value k y ′(l i The sum of squares of the residuals between ) should be minimized.

[0026] In step 4), the motor speed model is as follows:

[0027]

[0028]

[0029] Where, ω x and ω y These are the rotational speeds of the yaw motor and pitch motor in the laser tracking control system, respectively; k x (l) and k y (l) represents the tracking control fitting parameters of the position to be measured in the x and y directions, respectively, where l is the distance between the position to be measured and the laser tracking control system; Δx and Δy are the x-direction offset and y-direction offset of the backlight spot of the target mirror measured by the position sensitive detector (PSD) in the laser tracking control system, respectively, and R is the non-response radius of the laser tracking control system.

[0030]

[0031]

[0032] Among them, L respectively x and L y V represents the resistivity lengths of the photosensitive surface in the x and y directions, respectively; x V y and V sum These are the position voltage signals output by the PSD, V x =R f ×[(I A +I C )-(I B +I D )]、V y =R f ×[(I A+I B )-(I C +I D )]、V sum =R f ×(I A +I B +I C +I D ),I<00000​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​When the position of the target mirror changes within the calibration distance range, the to-be-measured position and its tracking control fitting parameters in the x and y directions are updated, the rotation speeds of the yaw motor and the pitch motor in the laser tracking control system under the current to-be-measured position are obtained, and then input into the servo driver in the laser tracking control system to control the rotation of the yaw motor and the pitch motor, thereby driving the second mirror to rotate and change the pointing of the measurement beam, until the outgoing light of the laser tracking control system is aligned with the center of the target mirror, thereby realizing distance-adaptive wide-range laser real-time tracking control.

[0036] The present application has the following advantages:

[0037] 1) The control method of the present application adopts the least square polynomial fitting to construct a tracking control parameter model of the motor rotation speed at a long distance, accurately calibrates the corresponding relationship between the measurement distance and the tracking control parameter, ensures the stability of the long-distance measurement tracking system, and improves the tracking stability and measurement accuracy.

[0038] 2) The control method of the present application can update the tracking control parameter that is accurately matched with the current distance in real time according to the change of the tracking distance, so that the tracking system can realize stable tracking of the target mirror at both the near end and the far end, and realize automatic tracking control with distance adaptation in a wide range.

[0039] The present application makes the tracking control parameter matched at any distance within the calibration range, reduces the influence of the mismatch between the measurement distance and the tracking control parameter on the long-distance tracking, and improves the stability of the wide-range tracking measurement of the laser tracker. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a principle block diagram of the laser tracking control system;

[0041] Figure 2 It is a flowchart of the wide-range laser tracking control method based on distance adaptation;

[0042] Figure 3 It is a tracking control parameter distance adaptation model obtained by adopting the least square polynomial fitting;

[0043] In the figure: 1, programmable multi-axis motion control card, 2, angle protocol adapter, 3, first servo driver, 4, second servo driver, 5, position sensitive detector, 6, digital-to-analog converter, 7, first circular grating angle encoder, 8, pitch motor, 9, yaw motor, 10, second circular grating angle encoder, 11, absolute distance measurement unit, 12, beam splitter prism, 13, optical filter, 14, first lens, 15, second lens, 16, first mirror, 17, second mirror, 18, target mirror, 19, computer. DETAILED DESCRIPTION

[0044] The application will be described in further detail below with reference to the drawings and specific embodiments.

[0045] As Figure 1 shown, the laser tracking control system used in the embodiment of the application comprises a programmable multi-axis motion control card 1, an angle protocol adapter 2, a first servo driver 3, a second servo driver 4, a position sensitive detector 5, a digital-to-analog converter 6, a first circular grating angle encoder 7, a tilt motor 8, a yaw motor 9, a second circular grating angle encoder 10, an absolute distance measurement unit 11, a beam splitter prism 12, a filter 13, a first lens 14, a second lens 15, a first mirror 16, a second mirror 17, a target mirror 18 and a computer 19.

[0046] The output end of the position sensitive detector 5 is connected to the input end of the digital-to-analog converter 6, and the output end of the digital-to-analog converter 6 is connected to the input end of the programmable multi-axis motion control card 1 to transmit the spot offset to the multi-axis motion control card 1. The input end of the first servo driver 3 and the second servo driver 4 is connected to the output end of the programmable multi-axis motion control card 1, and the input end of the tilt motor 8 and the yaw motor 9 is respectively connected to the output end of the first servo driver 3 and the second servo driver 4. The output end of the first circular grating angle encoder 7 and the second circular grating angle encoder 10 is connected to the input end of the angle protocol adapter 2, and the output end of the angle protocol adapter 2 is connected to the input end of the programmable multi-axis motion control card 1. The first circular grating angle encoder 7 and the second circular grating angle encoder 10 rotate coaxially with the tilt motor 8 and the yaw motor 9, respectively. The absolute distance measurement unit 11 measures the absolute distance from the target mirror to the tracker and provides a spot offset detection light source for the position sensitive detector 5. The first lens 14 and the second lens 15 keep the spot size consistent in a long distance range, and the return light spot diameter is within the effective detection range of the position sensitive detector 5.

[0047] When the laser tracking control system is working, the absolute distance measuring unit 11 simultaneously emits measuring beams of 780 nm and 633 nm wavelengths, which are collimated and shaped by the first lens 14 and the second lens 15, and then reflected by the first mirror 16 and the second mirror 19 to the target mirror; the measuring beams return to the original path after being reflected by the target mirror 18, and then transmitted into the absolute distance measuring unit 11 for interference distance measurement after passing through the beam splitter prism 12; the reflected light is filtered by the optical filter 13 to remove the 780 nm wavelength light, and then the 633 nm wavelength light irradiates the position sensitive detector 5 for spot offset detection. The position sensitive detector 5 detects the position deviation of the light spot, and outputs the offset signal to the digital-to-analog converter 6; the programmable multi-axis motion control card 1 sends the rotation speed control instructions of the pitch motor 8 and the yaw motor 9 to the first servo driver 3 and the second servo driver 4 according to the spot offset information collected by the digital-to-analog converter 6 and the absolute distance information measured by the absolute distance measuring unit 11, controls the rotation of the pitch motor 8 and the yaw motor 9 to drive the rotation of the second mirror 17, realizes the tracking of the target mirror 18, and determines the yaw angle and the pitch angle of the target mirror 18 relative to the center of the coordinate system by reading the angle information output by the first circular grating angle encoder 7 and the second circular grating angle encoder 10 through the angle protocol adapter 2, calculates the three-dimensional coordinates of the target mirror 18 in space in combination with the absolute distance information, and transmits the measurement results to the computer 19.

[0048] The specific implementation steps of the distance adaptive large-range laser tracking control method are as follows:

[0049] 1) Establish a distance adaptive tracking control model of the laser tracking control system.

[0050] In step 1), the distance adaptive tracking control model is as follows:

[0051] k x (l)=a x0 +a x1 l+a x2 l 2 +···+a xm l m

[0052] k y (l)=a y0 +a y1 l+a y2 l 2 +···+a ym l m

[0053] Wherein, k x (l) and k y(l) is a tracking control parameter at the to-be-measured position in the x and y directions, respectively, and l is a distance between the to-be-measured position and the laser tracking control system, that is, a current tracking distance value at the to-be-measured position; α x0 , α x1 … α xm are 0, 1, …, m order coefficients in the x direction, respectively, α y0 , α y1 … α ym are 0, 1, …, m order coefficients in the y direction, respectively.

[0054] 2) Calibrate the tracking control parameters of the laser tracking control system to obtain a calibration data set.

[0055] In step 2), the tracking control parameters of the laser tracking control system are calibrated. First, the center of the target mirror 18 in the laser tracking control system is aligned with the outgoing light of the laser tracking control system, then n sampling points are selected at equal intervals within the preset calibration distance range of the laser tracking control system, the target mirror 18 is installed on the circular trajectory generator and placed at each sampling point, the target mirror 18 is rotated at a preset tracking speed using the circular trajectory generator, the tracking control calibration parameters of the target mirror 18 at each sampling point are obtained, and the calibration data set of the laser tracking control system is constructed according to the distance positions of each sampling point and each tracking control calibration parameter.

[0056] The tracking range of the laser tracking control system includes an angle range and a distance range. The tracking speed is the linear rotational speed.

[0057] 3) Establish a least squares objective function of the laser tracking control system, input the calibration data set into the least squares objective function, calculate to obtain the coefficients of each order of the polynomial, input the coefficients of each order of the polynomial and the current tracking distance value at the to-be-measured position into the distance adaptive tracking control model, and the distance adaptive tracking control model outputs the matched tracking control parameters.

[0058] In step 3), the least squares objective function is as follows:

[0059]

[0060]

[0061] Wherein, F x (a) and F y (a) are the least squares objective functions based on the coefficients a of each order of the polynomial in the x and y directions, respectively; n is the number of sampling points; α x0 , α x1 … α xm are 0, 1, …, m order coefficients in the x direction, respectively, α y0 , α y1…α ym are 0, 1 …m order coefficients in y direction respectively; l i is the distance between the i th sampling point position and the laser tracking control system, i = 1, 2, …, n; k x ′(l i ) are the calibration tracking control parameters of the i th sampling point position in x and y directions respectively. y i i i x i x i y i y i x y x y The distance between the i th sampling point position and the laser tracking control system l

[0062] The distance between the i th sampling point position and the laser tracking control system l

[0062] The calibration tracking control parameters of the i th sampling point position in x and y directions.

[0063] The least square method is used to solve the least square objective function, and the polynomial coefficients a including 0, 1 …m order coefficients in x and y directions are obtained; the polynomial coefficients a are brought into the distance adaptive tracking control model to obtain the final distance adaptive tracking control model.

[0064] When controlling, the target mirror 18 is placed at the to-be-measured position, and the to-be-measured position is within the calibration distance range.

[0065] According to the least square method, for each l i The square sum of the residual between the fitting value k x (l i ) and the calibration value k x ′(l i ) should be minimum, and the square sum of the residual between the fitting value k y (l i ) and the calibration value k y ′(l i ) should be minimum.

[0066] 4) A motor speed model of the laser tracking control system is established, the tracking control parameters are input into the motor speed model, and the motor speed model outputs the motor speed.

[0067] In step 4), the motor speed model is as follows:

[0068]

[0069]

[0070] Wherein, ω x and ω y are the speeds of the yaw motor 9 and the pitch motor 8 in the laser tracking control system respectively; k x (l) and k y(l) are the tracking control fitting parameters in x and y directions at the position to be measured, respectively, and l is the distance between the position to be measured and the laser tracking control system; Δx and Δy are the x and y direction offset amounts of the light spot of the target mirror 18 measured by the position sensitive detector 5 (PSD) in the laser tracking control system, respectively, and R is the non-response radius of the laser tracking control system.

[0071]

[0072]

[0073] wherein, respectively, L x and L y are the resistance lengths of the x and y direction photosensitive surfaces; V x , V y and V sum are the position voltage signals output by the PSD, V x = R f × [(I A + I C ) - (I B + I D )], V y = R f × [(I A + I B ) - (I C + I D )], V sum = R f × (I A + I B + I C + I D ), I A , I B , I C and I D are the four light currents associated with the position of the light spot generated by the four electrodes of the PSD photosensitive surface, respectively; and R f is the equivalent resistance of the signal processing circuit in the PSD detector.

[0074] 5) Based on the motor speed in step 4), the motor speed of the laser tracking control system is controlled in real time using the distance adaptive light spot offset compensation tracking control strategy, and finally the distance adaptive large range laser tracking control is completed.

[0075] In step 5), the distance adaptive light spot offset compensation tracking control strategy is as follows:

[0076] In the photosensitive surface area of the position-sensitive detector 5PSD, when -R < Δx < R, the reflected light beam of the target mirror 18 has no offset in the x direction, and the rotational speed ω of the yaw motor 9 x is set to 0; when Δx < -R or Δx > R, the rotational speed ω of the yaw motor 9 x is set to the rotational speed of the yaw motor 9 output in step 4). At this time, the rotational speed ω of the yaw motor 9 x is jointly determined by the tracking control fitting parameter k x (l) and the offset Δx of the light spot in the x direction. When the tracking distance of the target mirror 18 remains unchanged, that is, k x (l) remains unchanged, the rotational speed ω of the yaw motor 9 x has a linear relationship with the light spot offset Δx; when -R < Δy < R, the reflected light beam of the target mirror 18 has no offset in the y direction, and the rotational speed ω of the pitch motor 8 y is set to 0; when Δy < -R or Δy > R, the rotational speed ω of the pitch motor 8 y is set to the rotational speed of the pitch motor 8 output in step 4). At this time, the rotational speed ω of the pitch motor 8 y is jointly determined by the tracking control parameter k y (l) and the offset Δy of the light spot in the y direction. When the tracking distance of the target mirror 18 remains unchanged, that is, k y (l) remains unchanged, the rotational speed ω of the yaw motor 8 y has a linear relationship with the light spot offset Δy.

[0077] When the position of the target mirror 18 changes within the calibration distance range, update the position to be measured and its tracking control fitting parameters in the x and y directions, and obtain the rotational speeds of the yaw motor 9 and the pitch motor 8 in the laser tracking control system at the current position to be measured. Then input them into the servo drivers 3 and 4 in the laser tracking control system to control the rotation of the yaw motor 9 and the pitch motor 8, driving the second reflector 17 to rotate to change the direction of the measurement beam until the outgoing light of the laser tracking control system is aligned with the center of the target mirror 18, realizing large-range laser real-time tracking control with distance adaptability.

[0078] As Figure 2 shown, it is the specific implementation flowchart of the method of the present invention. Before tracking the target mirror 18, when the light intensity V sum detected by the PSD is less than the specific threshold V T , it is regarded as having no reflected light, that is, the measurement beam does not irradiate the target mirror 18. At this time, it is necessary to manually adjust the position of the target mirror 18 or the direction of the system measurement beam until the measurement beam irradiates the target mirror 18.

[0079] As Figure 3 shown, there are 11 sample points at two groups of different distances (l i , k x'(l i )) and (l i ,k y '(l i )) as the calibration data set, a least square polynomial fitting is adopted. It can be seen that, as the tracking distance increases, the target mirror 18 moves along the tangential direction of the measuring beam by the same distance, the angle of the motor required to complete the tracking is different, and therefore a distance adaptive coefficient k x (l) and k y (l) is introduced into the speed model of the yaw motor 9 and the pitch motor 8 to optimize the motor speed at different tracking distances, so that the large-size distance adaptive automatic tracking control can be realized, the stability of the near-far end tracking system under large-size measurement is ensured, and the tracking stability and the measurement accuracy are improved.

[0080] In the embodiment of the present application, the PSD is a four-side type two-dimensional position sensor from Thorlabs, the sensitive area size of the sensor is 9mmx9mm, the effective detection diameter of the light spot is 0.2-7mm, the voltage noise is 2mV, the output voltage range is-4V-+4V, when the measuring beam is locked to the center of the target mirror 18, the light intensity detected by the PSD is V sum 2.3V, the threshold value V T is set to 2.0V, and the non-response radius of the tracking control system on the photosensitive surface of the PSD is set to 0.1mm.

[0081] The above specific embodiments are used to explain and illustrate the present application, rather than limit the present application, and any modification and change made to the present application within the spirit and protection scope of the claims of the present application, falls into the protection scope of the present application.

Claims

1. A distance adaptive based wide range laser tracking control method, characterized in that, The method comprises the following steps: 1) establishing a distance adaptive tracking control model of the laser tracking control system; 2) calibrating tracking control parameters of the laser tracking control system to obtain a calibration data set; 3) establishing a least squares objective function of the laser tracking control system, inputting the calibration data set into the least squares objective function, and calculating to obtain polynomial coefficients of each order; inputting the polynomial coefficients of each order and the current tracking distance value at the to-be-measured position into the distance adaptive tracking control model, and outputting matching tracking control parameters from the distance adaptive tracking control model; 4) establishing a motor speed model of the laser tracking control system, inputting the tracking control parameters into the motor speed model, and outputting the motor speed from the motor speed model; 5) using a distance adaptive spot offset compensation tracking control strategy to control the motor speed of the laser tracking control system in real time according to the motor speed in step 4), and finally completing the distance adaptive large-range laser tracking control. In step 1), the distance adaptive tracking control model is as follows: wherein k x (l) and k y (l) are tracking control parameters in x and y directions at the position to be measured, respectively, and l is the distance between the position to be measured and the laser tracking control system, i.e. the current tracking distance value at the position to be measured; α x0 , α x1 … α xm are 0, 1…m order coefficients in the x direction, respectively, and α y0 , α y1 … α ym are 0, 1…m order coefficients in the y direction, respectively.

2. The distance-adaptive based large-range laser tracking control method according to claim 1, characterized in that: In step 2), the tracking control parameters of the laser tracking control system are calibrated as follows: first, the center of a target mirror (18) in the laser tracking control system is aligned with the outgoing light of the laser tracking control system, then n sampling points are selected at equal intervals within a preset calibration distance range of the laser tracking control system, the target mirror (18) is installed on a circular trajectory generator and placed at each sampling point, the circular trajectory generator is used to drive the target mirror (18) to rotate at a preset tracking speed, tracking control calibration parameters of the target mirror (18) at each sampling point are obtained, and a calibration data set of the laser tracking control system is constructed according to the distance positions of the sampling points and the tracking control calibration parameters.

3. The distance-adaptive based large-range laser tracking control method according to claim 2, wherein: In step 3), the least squares objective function is as follows: wherein F x (a) and F y (a) are least square objective functions based on polynomial coefficients a of each order in x and y directions, respectively; n is the number of sampling points for calibration; α x0 , α x1 , …, α xm are 0, 1, …, m order coefficients in x direction, respectively; α y0 , α y1 , …, α ym are 0, 1, …, m order coefficients in y direction, respectively; l i is the distance between the i-th sampling point position and the laser tracking control system, i = 1, 2, …, n; k x ′ (l i ) and k y ′ (l i ) are the calibration tracking control parameters of the i-th sampling point position in x and y directions, respectively; The distance I between the i-th sampling point position and the laser tracking control system is included in the calibration data set i and the calibration tracking control parameters of the i-th sampling point position in the x and y directions; The least squares objective function is solved by using the least squares method to obtain polynomial coefficients a of each order, including 0, 1, …, m order coefficients in the x and y directions; the polynomial coefficients of each order are input into the distance adaptive tracking control model to obtain the final distance adaptive tracking control model; In the control, the target mirror (18) is placed at the to-be-measured position, and the to-be-measured position is within the calibration distance range.

4. The distance-adaptive based large-range laser tracking control method according to claim 2, wherein: In step 4), the motor speed model is as follows: wherein ω x and ω y are the rotational speeds of the yaw motor (9) and the pitch motor (8) in the laser tracking control system, respectively; k x (l) and k y (l) are the tracking control fitting parameters in the x and y directions at the position to be measured, respectively, and l is the distance between the position to be measured and the laser tracking control system; Δx and Δy are the x direction and y direction offset amounts of the light spot of the target mirror (18) measured by the position sensitive detector (5) PSD in the laser tracking control system, respectively, and R is the non-response radius of the laser tracking control system.

5. The distance-adaptive based large-range laser tracking control method according to claim 4, characterized in that: In step 5), the distance adaptive spot offset compensation tracking control strategy is as follows: In the light-sensitive surface area of the position-sensitive detector (5) PSD, when -R < Δx < R, the light beam of the target mirror (18) has no deviation in the x direction, the rotating speed ω x of the yaw motor (9) is set to 0; when Δx < -R or Δx > R, the rotating speed ω x of the yaw motor (9) is set to the rotating speed output in step 4); when -R < Δy < R, the light beam of the target mirror (18) has no deviation in the y direction, the rotating speed ω y of the pitch motor (8) is set to 0; when Δy < -R or Δy > R, the rotating speed ω y of the pitch motor (8) is set to the rotating speed output in step 4). When the position of the target mirror (18) in the calibration distance range changes, the to-be-measured position and the tracking control fitting parameters thereof in the x and y directions are updated, the speeds of the yaw motor (9) and the pitch motor (8) under the current to-be-measured position are obtained, and then input into the servo drivers (3, 4) in the laser tracking control system to control the rotation of the yaw motor (9) and the pitch motor (8), until the outgoing light of the laser tracking control system is aligned with the center of the target mirror (18), and the distance adaptive large-range laser real-time tracking control is realized.

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