JP7112296B2 - LASER TRACKING DEVICE AND METHOD OF CONTROLLING LASER TRACKING DEVICE - Google Patents

Description

The present invention relates to a laser tracking device and a control method for a laser tracking device.

Conventionally, there is known a laser tracking device such as a laser tracker that irradiates a target fixed to a moving object with a laser beam and changes the irradiation direction of the laser beam so as to track the target (for example, Patent Document 1 reference).
The laser tracker described in Patent Document 1 includes a laser interferometer, a biaxial rotation mechanism for directing the optical axis direction of a laser beam (output light) output from the laser interferometer in an arbitrary direction, and a retroreflector as a target. and a detection sensor for detecting the deviation of the optical axis of the return light (reflected light) reflected by. This laser tracker uses a detection sensor to detect the deviation between the emitted light and the incident light, feedback-controls the biaxial rotation mechanism so that the emitted light and the incident light are coaxial, and the emitted light is placed at the center of the retroreflector. Make it track as it is illuminated.

JP 2009-229066 A

By the way, the laser tracker described in Patent Document 1 and the like may be used to measure the dynamic position of the spindle with respect to the table in machine tools and three-dimensional measuring devices. In such a case, the target provided on the spindle may not only move in one direction, but also move in the opposite direction after temporarily stopping.
However, in the laser tracker described in Patent Document 1 and the like, when the target resumes moving in the direction opposite to that before it stopped, the response speed for resuming movement of the target is slower than when it resumes moving in the same direction as before it stopped. It is slow, and the tracking delay amount of the laser beam with respect to the target becomes large. That is, in the laser tracker described in Patent Document 1 and the like, when the target repeatedly stops moving and restarts moving, the tracking characteristics vary depending on the moving direction of the target.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser tracking device and a method of controlling the laser tracking device that can suppress variations in tracking characteristics.

A laser tracking device of the present invention includes a laser light source that emits laser light, an optical axis shift detection unit that detects an optical axis shift amount between the emitted light emitted from the laser light source and the reflected light reflected by a target, a rotation mechanism that rotates the laser light source based on an input torque command; an angular velocity detection unit that detects the angular velocity at which the laser light source rotates; and a speed command unit that outputs a speed command based on the amount of optical axis deviation. a torque command that has an integrator that integrates a speed deviation between the speed command and the angular velocity, calculates an integral control value based on the integral value of the speed deviation, and outputs the torque command that includes the integral control value; and a reset unit that resets the integrator to an initial state when each of the absolute values of the optical axis deviation amount and the angular velocity reaches a threshold value or less.

In the present invention, the speed command unit outputs a speed command based on the optical axis shift amount detected by the optical axis shift detection unit, and the torque command unit outputs a speed command between the angular speed detected by the angular speed detection unit and the speed command. Integrate the deviation with an integrator. Then, the torque command section calculates an integral control value based on the integral value of the speed deviation, and outputs a torque command including the integral control value.
When the target starts moving, the integrator accumulates the integral value of the speed deviation and increases the integral control value, thereby outputting a torque command for generating starting torque in the rotating mechanism. Thereby, the rotation mechanism is driven and controlled so that the laser light source tracks the dynamic position of the target.

Here, if the integrator is not reset as in the prior art, the integrator would maintain the integrated value accumulated for generating the starting torque in the rotating mechanism even after the target stops moving. , the integral control value is maintained at a predetermined value instead of 0 (the reset value).
Therefore, when the target resumes moving in the direction opposite to that before the movement was stopped, the torque command unit sets the integral control value maintained at the predetermined value to a value opposite in sign to the predetermined value (inversely to the rotation mechanism). value that generates starting torque in the direction). For this reason, the time required from the resumption of movement of the target to the start of the rotation mechanism is longer than when the movement of the target is started for the first time.
On the other hand, when the target resumes moving in the same direction as before it stopped moving, the torque command section can use the integral control value maintained at the predetermined value, so it can immediately output a torque command for rotating the rotating mechanism. . Therefore, the time required from the resumption of movement of the target to the start of the rotation mechanism is shorter than when the movement of the target is started for the first time.

In contrast, in the present invention, the reset unit resets the integrator to the initial state when the absolute values of the optical axis shift amount and the angular velocity reach the respective threshold values or less. The thresholds for the amount of optical axis deviation and the angular velocity can be set arbitrarily.
According to such a configuration, after the target temporarily stops moving, the torque will The command section may change the integral control value from the reset value. Therefore, the time taken from the resumption of movement of the target to the start of the rotation mechanism, that is, the response speed in response to the resumption of movement of the target is the same in both cases. As a result, in the laser tracker, variations in tracking characteristics depending on the moving direction of the target are suppressed.

In the laser tracking device of the present invention, it is preferable that the reset unit resets the integrator when the optical axis shift amount and the angular velocity each reach zero.
In the present invention, when the target does not stop moving and continues to move in one direction, the integral control value is maintained, thereby suppressing a decrease in responsiveness.

A control method for a laser tracking device according to the present invention includes a laser light source that emits laser light, and optical axis deviation detection that detects an optical axis deviation amount between the emitted light emitted from the laser light source and the reflected light reflected by a target. a rotation mechanism that rotates the laser light source based on the input torque command; an angular velocity detection unit that detects the angular velocity at which the laser light source rotates; and a speed that outputs a speed command based on the optical axis deviation amount. and an integrator that integrates a speed deviation between the speed command and the angular velocity, calculates an integral control value based on the integral value of the speed deviation, and outputs the torque command including the integral control value. and a torque command unit for performing a process of resetting the integrator to an initial state when each of the absolute values of the optical axis deviation amount and the angular velocity reaches a threshold value or less. Characterized by
According to the present invention, the same effects as those of the above-described laser tracking device of the present invention can be obtained.

1 is a schematic diagram showing the configuration of a laser tracker according to one embodiment of the present invention; FIG. FIG. 2 is a block diagram showing the internal configuration of the laser tracker of this embodiment; FIG. 2 is a block diagram showing the first drive control section of the laser tracker of the embodiment; FIG. 4 is a block diagram showing a second drive control section of the laser tracker of the embodiment; 4 is a flow chart showing a drive control method in the laser tracker of the present embodiment; 7 is a graph showing an example of temporal changes in the position of the target, the angular velocity of the first motor, the amount of optical axis deviation, and the torque command in the comparative example. 8 is a graph showing another example of temporal changes of the position of the target, the angular velocity of the first motor, the amount of optical axis deviation, and the torque command in the comparative example. 5 is a graph showing an example of temporal changes in the position of the target, the angular velocity of the first motor, the amount of optical axis deviation, and the torque command in this embodiment.

An embodiment of the present invention will be described below.
In FIG. 1, the laser tracker 1 of this embodiment is a device that measures the distance from the laser tracker 1 to the target 6 while tracking the dynamic position of the target 6 moving in three-dimensional space.
The target 6 is, for example, a retroreflector such as a retroreflector, and is attached to the head 5 of a moving mechanism (not shown). The moving mechanism drives the head 5 to move the target 6 in three-dimensional space. Specific examples of the moving mechanism include a machine tool, a three-dimensional measuring device, and the like that three-dimensionally move the main shaft as the head 5 with respect to the table.

[Configuration of laser tracker 1]
The configuration of the laser tracker 1 will be described with reference to FIGS. 1 and 2. FIG.
The laser tracker 1 includes a biaxial rotation mechanism 2 , a laser interferometer 3 supported by the biaxial rotation mechanism 2 , and a controller 4 that drives and controls the biaxial rotation mechanism 2 .

The biaxial rotation mechanism 2 includes a base 21, a first support portion 22 and a second support portion 23, as shown in FIG.
The base 21 is placed (or fixed) on a stage of a machine tool, a three-dimensional measuring device, or the like.
The first support portion 22 is rotatably supported by the base 21 about the axis A1. The axis A1 is, for example, an axis orthogonal to the upper surface of the stage.
The second support portion 23 is supported by the first support portion 22 so as to be rotatable about the axis A2. The axis A2 is an axis that intersects (orthogonally in this embodiment) the axis A1.
The intersection of the axis A1 and the axis A2 is the measurement reference point in the laser tracker 1. FIG.

The biaxial rotation mechanism 2 also includes a first drive section 24 and a second drive section 25, as shown in FIG.
The first driving section 24 has a first motor 241 that rotationally drives the first support section 22 and a first encoder 242 that detects the rotation angle of the first support section 22 . The first encoder 242 detects the rotation angle (azimuth angle θ) of the first support portion 22 from a predetermined origin position.
The second drive section 25 has a second motor 251 that rotationally drives the second support section 23 and a second encoder 252 that detects the rotation angle of the second support section 23 . The second encoder 252 detects the rotation angle (elevation angle φ) of the second support portion 23 from the predetermined origin position.

The laser interferometer 3 is supported by the second support portion 23 of the biaxial rotation mechanism 2, as shown in FIG. The attitude of the laser interferometer 3 is changed by each rotation of the first support section 22 and the second support section 23 . Specifically, the direction in which the laser beam is emitted from the laser interferometer 3 is changed in azimuth by the rotation of the first support 22 and changed in elevation by the rotation of the second support 23 .

Further, the laser interferometer 3 includes a laser light source 31, a light receiving section 32, and an optical axis deviation detection section 33, as shown in FIG.
The laser light source 31 emits laser light (output light Lo) in an arbitrary direction (azimuth θ, elevation angle φ). The laser light retroreflected by the target 6 (reflected light Lr) enters the laser interferometer 3 .
The light receiving unit 32 receives interference light between the emitted light Lo and the reflected light Lr, and outputs a light reception signal corresponding to the interference light to the control unit 4 .

The optical axis deviation detection unit 33 detects the amount of optical axis deviation between the emitted light Lo and the reflected light Lr, and outputs the detected amount to the control unit 4 . The optical axis deviation amount detected by the optical axis deviation detection unit 33 is the optical axis deviation amount d1 in the rotation direction (azimuth direction) of the first support part 22 and the optical axis deviation amount d1 in the rotation direction (elevation angle direction) of the second support part 23. and an axis deviation amount d2 (see FIG. 1).
A conventional configuration can be used for the specific configuration of the optical axis deviation detection unit 33 . For example, when adopting the configuration described in Japanese Patent Application Laid-Open No. 2007-309677, the optical axis deviation detection unit 33 reflects each of the emitted light Lo and the reflected light Lr to the light spot position detection element by a semi-transmissive mirror, A positional deviation amount between the spot position of the emitted light Lo and the spot position of the reflected light Lr in the light spot position detecting element is detected.

The controller 4 is connected to the laser interferometer 3 and the biaxial rotation mechanism 2, respectively, as shown in FIG.
The length measurement unit 41 calculates the distance from the measurement reference point to the target 6 based on the received light signal from the laser interferometer 3 .

The first drive control unit 42 and the second drive control unit 43 drive and control the biaxial rotation mechanism 2 so that the laser light emitted from the laser interferometer 3 tracks the target 6 .
Specifically, the first drive control unit 42 drives and controls the first motor 241 based on the optical axis shift amount d1 in the azimuth direction. The second drive control unit 43 drives and controls the second motor 251 in the elevation direction based on the optical axis shift amount d2.

[Configuration of Drive Control Unit]
Next, each configuration of the first drive control section 42 and the second drive control section 43 will be described. Note that the first drive control section 42 and the second drive control section 43 have substantially the same configuration except that the drive control targets are different. Therefore, the first drive control unit 42 will be mainly described below with reference to FIG.

As shown in FIG. 3 , the first drive control section 42 has an angular velocity detection section 421 , a speed command section 422 , a torque command section 423 and a reset section 424 .
The angular velocity detector 421 calculates the rotation angle (rotation amount) of the laser interferometer 3 about the axis A1 from the change in the azimuth angle θ detected by the first encoder 242, and detects the laser interferometer from the rotation angle per unit time. The angular velocity (rotational velocity) ω1 of 3 is calculated.

The speed command unit 422 calculates an angular speed command ωr1 indicating the target speed of the first motor 241 by proportional control based on the positional deviation between the optical axis shift amount d1 received from the optical axis shift detection unit 33 and the target value 0. .

The torque command unit 423 calculates a torque command Te1 corresponding to the torque generated by the first motor 241 by proportional integral control based on the speed deviation between the angular speed ω1 detected by the angular speed detection unit 421 and the angular speed command ωr1.
Specifically, the torque command unit 423 calculates a speed deviation, which is the difference between the angular speed ω1 and the angular speed command ωr1, and uses the speed deviation as the proportional control command. Also, an integral control value is calculated by calculating an integral value of the speed deviation and multiplying the integral value by an integral gain. By multiplying the sum of the integral control value and the proportional control command by a predetermined gain, the torque command Te1 is calculated and output to the first motor 241 .
Here, the torque command section 423 includes an integrator 44 for calculating the integrated value of the speed deviation.

According to the above configuration, the torque command Te1 calculated so that the optical axis shift amount d1 becomes 0 is input to the first motor 241 . The first motor 241 generates torque corresponding to the input torque command Te1, and rotationally drives the first support portion 22 . This allows the emitted light Lo to track the target 6 in the rotation direction (azimuth direction) of the first support portion 22 .

The reset unit 424 includes a reset circuit that discharges the electric charge of the integration capacitor of the integrator 44. At the timing when the optical axis shift amount d1 and the angular velocity ω1 each reach 0, the integrator of the torque command unit 423 44 to its initial state.
When the integrator 44 is reset by the reset unit 424, the integral value of the speed deviation calculated by the integrator 44 becomes 0, and the integral control value calculated by multiplying the integral gain by the integral value also becomes 0.

The above description can be applied to the second drive control unit 43 by replacing the azimuth angle θ with the elevation angle φ and the optical axis offset amount d1 with the optical axis offset amount d2.
Specifically, as shown in FIG. 4 , the second drive control section 43 has an angular velocity detection section 431 , a speed command section 432 , a torque command section 433 and a reset section 434 . The angular velocity detector 431 calculates an angular velocity ω2 in the elevation direction from the change in the elevation angle φ detected by the second encoder 252, and the velocity command part 432 calculates an angular velocity command ωr2 based on the optical axis deviation d2. The torque command unit 433 calculates a torque command Te2 for the second motor 251 based on the angular velocity ω2 and the angular velocity command ωr2. The reset unit 434 resets the integrator 45 of the torque command unit 433 to the initial state at the timing when the optical axis shift amount d2 and the angular velocity ω2 each reach zero.

[Drive control method]
A drive control method for the first motor 241 will be described with reference to the flowchart shown in FIG. 5, taking the first drive control unit 42 as an example.
As shown in FIG. 5, when the laser tracker 1 is activated, the first drive control unit 42 controls the first drive control unit 42 so that the optical axis shift amount d1 between the emitted light Lo and the reflected light Lr becomes zero in the azimuth angle direction. The motor 241 is driven and controlled to adjust the emitting direction of the emitted light Lo and align it with the target 6 (step S1).

After that, the first drive control unit 42 starts controlling the laser beam to track the detected target 6 (step S2). Specifically, the angular velocity detection unit 421, the speed command unit 422, and the torque command unit 423 output the torque command Te1 calculated so that the optical axis shift amount d1 becomes 0, and control the driving of the first motor 241. .

During tracking control, the reset unit 424 determines whether or not the optical axis deviation amount d1 has become 0 (step S3), and if YES, determines whether or not the angular velocity ω1 has become 0 (step S4). In the case of YES in step S4, the reset unit 424 resets the integrator 44 to the initial state (step S5), and returns to step S3.
That is, during tracking control, the reset unit 424 continues to monitor the optical axis deviation amount d1 and the angular velocity ω1, and repeats resetting the integrator 44 when both values become zero.
The order of steps S3 and S4 may be reversed. Moreover, the above description can also be applied to the drive control method of the second motor 251 by the second drive control section 43 .

[Comparison with Comparative Example]
The tracking characteristics of the laser tracker 1 according to this embodiment will be specifically described using a comparative example.
Note that the laser tracker of the comparative example has the same configuration as that of the present embodiment except that it does not have the reset units 424 and 434 of the present embodiment, and will be described using the same reference numerals as those of the present embodiment. In the following, the tracking characteristics when driving and controlling the first motor 241 will be described as an example.

First, a comparative laser tracker will be described.
In FIG. 6, when the target 6 starts moving in one direction at an arbitrary time t0 and the absolute value of the optical axis deviation d1 increases, the torque command Te1 is calculated so that the optical axis deviation d1 becomes 0. be increased. When the torque generated by the torque command Te1 exceeds the starting torque (time t1), the first motor 241 starts and the absolute value of the angular velocity ω1 starts increasing. Note that the torque command Te1 becomes a value exceeding the starting torque as a result of the integrator 44 accumulating the integral value of the speed deviation and increasing the integral control value.
Here, when the time from the time when the target 6 starts moving to the time when the first motor 241 is started is the start preparation time, the time from time t0 to time t1 is the start preparation time Tp11.
After the angular velocity ω1 reaches a predetermined speed (after time t2), the proportionally controlled torque command Te1 stabilizes the angular velocity ω1, and the optical axis shift amount d1 changes at a constant tracking delay amount D11.

When the movement of the target 6 stops at an arbitrary time t3, the optical axis shift amount d1 and the angular velocity ω1 both start to converge to zero. Here, the time when each value of the optical axis shift amount d1 and the angular velocity ω1 reaches 0 is defined as time t4.

On the other hand, the absolute value of the torque command Te1 starts decreasing at time t3 when the movement of the target 6 stops, but does not appear to converge to 0, and maintains a predetermined value even at time t4.
This is because the integrator 44 maintains an accumulated integrated value for generating starting torque. That is, at time t4, of the proportional control command and the integral control value, which are components of the torque command Te1, the proportional control command converges to 0, but the integral control value maintains a predetermined value.

After that, when the target 6 resumes moving in the same direction as before the stop at an arbitrary time t5, the torque command Te1 exceeds the starting torque by a small change because the integrated value is accumulated in the integrator 44. It reaches a value that generates torque, and the first motor 241 starts (time t6). The start preparation time Tp12 (time t5 to time t6) in this case is shorter than the initial start preparation time Tp11 (time t0 to time t1). Further, when the speed of the target 6 after resuming movement is the same as the speed at the time of initial movement, the tracking delay amount D12 after resuming movement is smaller than the initial tracking delay amount D11.

On the other hand, as shown in FIG. 7, when the target 6 resumes moving in the direction opposite to that before the stop at an arbitrary time t5, the torque command Te1 changes from a predetermined value on the plus side (or minus side) to the minus side (or positive side) (the value that causes the first motor 241 to generate starting torque in the opposite direction). Due to the time required for this change, the start preparation time Tp13 (time t5 to t6) becomes longer than the initial start preparation time Tp11 (time t0 to time t1). Further, when the speed of the target 6 after the resumption of movement is the same as the speed at the time of the initial movement, the tracking delay amount D13 after the resumption of movement is larger than the initial tracking delay amount D11.

As described above, in the laser tracker of the comparative example, when the target 6 resumes moving in the direction opposite to that before the stop, compared to when the target 6 resumes moving in the same direction as before the stop, the first The response speed of the motor 241 slows down. Further, even if the speed of the target 6 after the resumption of movement is the same as the speed at the time of the initial movement, the amount of tracking delay with respect to the target 6 increases.

Next, the laser tracker 1 of this embodiment will be described.
In this embodiment, as shown in FIG. 8, the same drive control as in the comparative example is performed until just before time t4 when the target 6 stops moving and each value of the optical axis shift amount d1 and the angular velocity ω1 reaches zero. will be Specifically, the absolute value of the torque command Te1 starts decreasing at time t3 when the movement of the target 6 stops, but does not appear to converge to 0, and maintains an integral control value of a predetermined value or more until immediately before time t4. is doing.

However, in this embodiment, when each value of the optical axis shift amount d1 and the angular velocity ω1 reaches 0 at time t4, the reset unit 424 performs the above-described steps S3 to S5. As a result, the torque command Te1 becomes 0 at time t4.

After that, at arbitrary time t5, when the target 6 resumes movement, the integrator 44 is in a reset state. Therefore, when the target 6 resumes moving in the same direction as before the stop (dotted line in FIG. 8), or when the target 6 resumes moving in the direction opposite to that before stopping (the solid line in FIG. 8). Even in this case, the torque command Te1 changes from the initial value of 0. Then, when the torque generated by the torque command Te1 exceeds the starting torque (time t6), the first motor 241 is started.

In this embodiment, regardless of whether the dashed line or the solid line in FIG. (from time t0 to time t1). That is, the response speed of the first motor 241 in response to resumption of movement of the target 6 is the same in both cases.
Further, when the speed of the target 6 after resuming movement is the same as the speed at the time of initial movement, the tracking delay amounts D2a and D2b after the resumption of movement of the target 6 are , equal to the initial tracking delay amount D1.
Therefore, in the laser tracker 1 of the present embodiment, variations in tracking characteristics due to the moving direction of the target 6 are suppressed as compared with the laser tracker of the comparative example.

[Effect of this embodiment]
In the laser tracker 1 of this embodiment, the reset unit 424 resets the integrator 44 to the initial state when the absolute values of the optical axis shift amount d1 and the angular velocity ω1 reach zero. Similarly, the reset unit 434 resets the integrator 45 to the initial state when the absolute values of the optical axis shift amount d2 and the angular velocity ω2 reach zero.
Therefore, the torque command units 423 and 433 are set to the integral control value should be changed from the reset value. For this reason, in the laser tracker 1 of the present embodiment, the response speeds for restarting the movement of the target 6 are the same in both cases. As a result, in the laser tracker 1, variations in tracking characteristics due to the moving direction of the target 6 are suppressed.
Further, in the present embodiment, when the target 6 does not stop moving and continues to move in one direction, the integral control value is maintained, so it is possible to suppress a decrease in responsiveness.

[Modification]
It should be noted that the present invention is not limited to the above-described embodiments, and includes modifications and the like within the scope of achieving the object of the present invention.

In the above embodiment, the reset unit 424 resets the integrator 44 when the optical axis shift amount d1 and the angular velocity ω1 reach zero, but the present invention is not limited to this.
For example, the reset unit 424 may reset the integrator 44 when the absolute values of the optical axis shift amount d1 and the angular velocity ω1 each reach a threshold value or less. The threshold values of the optical axis shift amount d1 and the angular velocity ω1 can be arbitrarily set, but they may be set to values reached immediately before the first motor 241 stops rotating, for example.
In such a modified example, by resetting the integrator 44 before the first motor 241 completely stops rotating, it is possible to shorten the time required from when the target 6 resumes movement to when the rotation mechanism starts. .

Further, in the above-described embodiment, the reset unit 424 resets when the absolute values of the optical axis shift amount d1 and the angular velocity ω1 reach 0 and then the optical axis shift amount d1 changes to a value opposite to that immediately before. , may reset the integrator 44 . It should be noted that the timing for resetting the integrator 44 is preferably the timing immediately after detecting that the optical axis shift amount d1 has changed to a value opposite to that immediately before.
In such a modification, when the target 6 resumes moving in the same direction as before the stop, the integral control value is not reset and changes from the accumulated predetermined value. Therefore, the response speed for resuming the movement of the target 6 can be improved more than when the target movement is started for the first time. On the other hand, when the target 6 resumes moving in the direction opposite to that before it stopped, the reset unit 424 resets the integrator 44 at the timing when it detects that the optical axis shift amount d1 has changed to a value opposite to that immediately before. do. As a result, since the integral control value can be changed from the reset value, the response to the resumption of movement of the target 6 is faster than the case where the integral control value is changed from the predetermined value by the proportional integral control without resetting the integrator 44. Can improve speed.
In the above modified example, there is a difference in the response speed for tracking the target 6 between when the target 6 resumes moving in the same direction as before it stopped and when the target 6 resumes moving in the opposite direction to that before it stopped. However, the difference is reduced from the prior art.
For this reason, such a modified example may be adopted when emphasizing the response speed when the target 6 resumes moving in the same direction as before the stop.

It should be noted that each modified example described above for the reset section 424 can also be applied to the reset section 434 in the same manner.

In the above embodiment, the laser tracker 1 has the biaxial rotation mechanism 2 that rotates the laser interferometer 3, but the present invention is not limited to this. That is, the laser tracker 1 may have a uniaxial rotation mechanism that rotates the laser interferometer 3, and either the azimuth angle or the elevation angle of the laser beam emission direction may be changed.

In the above embodiment, the laser tracker 1 that measures the distance between the target 6 and the measurement reference point by causing the target 6 to track the laser beam was exemplified as the laser tracking device of the present invention, but the present invention is not limited to this. For example, the laser tracking device of the present invention may be a device that only tracks the target 6 without the length measurement function.

INDUSTRIAL APPLICABILITY The present invention can be used for a laser tracking device, a laser tracker, or the like that tracks a target with a laser beam.

DESCRIPTION OF SYMBOLS 1... Laser tracker, 2... Biaxial rotation mechanism, 21... Base, 22... First support part, 23... Second support part, 24... First drive part, 241... First motor, 242... First encoder, 25 2nd driving part 251 2nd motor 252 2nd encoder 3 laser interferometer 31 laser light source 32 light receiving part 33 optical axis deviation detection part 4 control part 41 measurement Long part 42... First drive control part 43... Second drive control part 421, 431... Angular velocity detection part 422, 432... Speed command part 423, 433... Torque command part 424, 434... Reset part, 44... Integrator, 5... Head, 6... Target, A1, A2... Axes, d1, d2... Optical axis deviation amount, D1, D2a, D2b, D11, D12, D13... Tracking delay amount, Lo... Output light, Lr Reflected light t1 to t5 Time Te1, Te2 Torque command θ Azimuth angle φ Elevation angle ω1, ω2 Angular velocity ωr1, ωr2 Angular velocity command.

Claims (3)

a laser light source that emits laser light;
an optical axis deviation detection unit that detects an optical axis deviation amount between the emitted light emitted from the laser light source and the reflected light reflected by the target;
a rotating mechanism that rotates the laser light source based on an input torque command;
an angular velocity detector that detects the angular velocity of rotation of the laser light source;
a speed command unit that outputs a speed command based on the amount of optical axis deviation;
A torque command unit that has an integrator that integrates a speed deviation between the speed command and the angular velocity, calculates an integral control value based on the integral value of the speed deviation, and outputs the torque command that includes the integral control value. When,
and a reset unit that resets the integrator to an initial state when each of the absolute values of the optical axis deviation amount and the angular velocity reaches a threshold value or less. The laser tracking device according to claim 1,
The laser tracking device, wherein the reset unit resets the integrator when the optical axis shift amount and the angular velocity each reach zero. a laser light source that emits laser light;
an optical axis deviation detection unit that detects an optical axis deviation amount between the emitted light emitted from the laser light source and the reflected light reflected by the target;
a rotating mechanism that rotates the laser light source based on an input torque command;
an angular velocity detector that detects the angular velocity of rotation of the laser light source;
a speed command unit that outputs a speed command based on the amount of optical axis deviation;
A torque command unit that has an integrator that integrates a speed deviation between the speed command and the angular velocity, calculates an integral control value based on the integral value of the speed deviation, and outputs the torque command that includes the integral control value. and, in a laser tracking device comprising:
A method of controlling a laser tracking device, comprising resetting the integrator to an initial state when each of the absolute values of the optical axis deviation amount and the angular velocity reaches a threshold value or less.

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