JPH01282489A - Method for controlling tracking speed of moving body by laser beam - Google Patents

Abstract

PURPOSE:To smoothly perform tracking corresponding to the speed of a moving body, by calculating the relative angular velocity of the moving body and scanning beam from the change of the receiving position of return beam and accelerating or decelerating a tracking speed on the basis of said angular velocity. CONSTITUTION:The laser beam LB generated from a laser beam generator 110 scans a space to be incident to the reflective body 200 provided to a moving body 20 and reflected as return beam RB. At this time, when a beam receiving position is shifted, the beam receiving position signal detected by a position sensor 132 is inputted to polarity judge circuits 401, 402 and the circuits 401, 402 output tracking direction signals to motor driving circuits 415, 416. At the same time, the relative angular velocity of the moving body and laser beam is operated from the change quantity of the beam receiving position of the sensor 132 and the operation result is inputted to speed signal generating circuits 413, 414 which is turn output tracking speed signals to the circuits 415, 416. Therefore, the circuits 415, 416 drive X- and Y-axis pulse motors 123, 124 and a tracking speed is subjected to acceleration/deceleration control so that the relative angular velocity becomes zero.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method of tracking a moving object using a light beam, and in particular, a light beam that enables stable tracking even if the movement of the moving object suddenly changes. This invention relates to a tracking speed control method for a moving object.

<Conventional technology> Conventionally, as a device for tracking a moving object using a light beam,
A light beam generator, a light beam scanning means, a retroreflector provided on a moving body, a light receiving detector for receiving and detecting the light beam reflected by the retroreflector, and a controller for controlling the light beam scanning means based on the detection output. There are some that are equipped with. An overview of the device and tracking method will be explained below.

FIG. 8 is a schematic explanatory diagram showing an outline of a conventional device. The fixed station 10 of this device includes a scanning means 100 and a control section 300. The scanning means 100 includes a light beam generator 110 that generates a light beam LB;
A scanning mechanism 120 that emits a light beam LB generated from a light beam toward space to scan the space, and a light receiving detector 130 that receives and detects a return beam RB that is reflected by a retroreflector 200 provided on the moving body 20 and returns. It is composed of.

In detail, the light beam generator 110 and the light receiving detector 1
30 is integrally constructed so as to be the same as the optical axis of the generated light beam LB, and is fixed by a shafted support frame 121, which is connected to the frame 1.
22 so as to be rotatable.

The scanning mechanism 120 is formed in a U-shape and includes a Y-axis pulse motor 124 and an X-axis pulse motor 1 for rotating a frame 122 that pivotally supports the shafted support frame 121 in the Y-axis direction.
24 and an X-axis pulse motor 123 that rotates the frame body 122 in the X-axis direction.

The light beam LB from the light beam generator 110 scans the space by a scanning mechanism 120. On the other hand, the moving body 20 includes a retroreflector 2 such as a corner cube.
00 is provided, the scanned light beam LB is incident thereon, reflected by the retroreflector 200, and a return beam R is provided.
It returns to the fixed station 10 as B.

The light receiving detector 130 detects the positional deviation of the feedback beam RB, and has a large number of light receiving element groups arranged in four quadrants in a plate-like body having a passage hole 131 at its center.

When tracking is complete, the light beam LB enters the center of the retroreflector 200, and its return beam I? B
Since the return beam RB returns in the same direction as the light beam LB, the return beam RB passes through the passage hole 131 of the light receiving detector 130, and the light receiving detector 130 does not detect the light receiving. Furthermore, if the tracking is lost, the return beam RB will be displaced, and the passage hole 13
1@ does not pass, and the light receiving detector 130 detects the light receiving.

The light-receiving element group of the light-receiving detector 130 is predetermined by coordinates, and the control unit 300 rotates the scanning mechanism 120 in a direction in which the positional deviation of the return beam RB becomes zero based on a detection signal determined by the coordinates. Like X-axis pulse motor 123, Y-axis pulse motor 124
is controlled so that the light beam LB always tracks the center of the retroreflector 200.

FIG. 9 is a block diagram of the control section 300 of the conventional device.

The control unit 300 uses a light receiving position sensor 132 as a light receiving detector 130, and has an X-axis and Y credit polarity determination circuit 3.
01.302, X-axis, Y-axis motor drive circuit 303.3
04, a speed setter 305, and a speed signal generation circuit 306. The light receiving position of the feedback beam RB detected by the light receiving position sensor 132 is sent to the X-axis and Y-axis polarity determination circuit 30 as light receiving position signals for the X-axis and Y-axis, respectively.
1.302. X-axis, Y trust polarity discrimination circuit 3
01.302 is a positive value determined by the quadrant of the light receiving position signal.
The tracking direction is determined by determining the negative polarity, and is input as a tracking direction signal to the X-axis and Y-axis motor drive circuits 303 and 304.

The speed signal generation circuit 306 generates a tracking speed signal, and enables the scanning means 100 to perform tracking at a tracking speed preset by the speed setter 305.

This tracking speed signal is transmitted to the X-axis and Y-axis motor drive circuit 30.
3. Input to 304. This circuit moves in the direction indicated by the tracking direction signals X and Y at a speed corresponding to the tracking speed signal XIh.
The pulse motor 123 and the Y-axis pulse motor 124 are rotated. As a result, the scanning mechanism 120 rotates, and the direction of the light beam generator 110 is controlled so that the light beam LB is incident on the center of the retroreflector 200 of the moving body 20.

<Problems to be Solved by the Invention> In the conventional tracking speed control method of a moving object using a light beam as described above, the moving speed of the moving object is lower than the tracking speed set in advance by the tracking speed of the light beam generating means. If it is too early, the light beam will deviate from the retroreflector of the moving object, making it impossible to track the moving object. In order to avoid such a situation, it is conceivable to increase the tracking speed of the scanning means. However, if the tracking speed is set to a constant high speed, tracking becomes unstable when the moving object suddenly changes such as when it starts, stops, or changes direction, and in some cases, tracking becomes impossible. Ta.

The present invention was devised in view of the above circumstances, and an object of the present invention is to provide a method for controlling the tracking speed of a moving object using a light beam, which allows stable tracking even if the movement of the moving object changes suddenly.

<Means for Solving the Problems> A method for controlling the tracking speed of a moving object using a light beam according to the present invention includes: a light beam generator; a scanning means for scanning a light beam emitted from the light beam generator into space; a light-receiving detector that receives and detects a return beam that is reflected by a retroreflector provided on the moving body and returns back; and a control unit that determines the moving direction of the moving body based on the detection output of the light-receiving detector and controls the scanning means. In the method for tracking a moving object using a light beam, the relative angular velocity between the moving object and the scanned light beam is determined from a change in the light receiving position of the return beam detected by the light receiving detector, and this relative angular velocity becomes zero. The tracking speed of the scanning means is controlled to accelerate or decelerate.

Effect> The light beam generated from the light beam generator is emitted toward space and is scanned by the scanning means. When this light beam enters a retroreflector provided on the moving object, it returns as a return beam. Due to the movement of the moving object, the light receiving position of the feedback beam receiving detector shifts. The direction of change in the light receiving position is determined by a polarity determining circuit, and the result of this determination is input to the motor drive circuit as a tracking direction signal. On the other hand, the relative angular velocity between the moving body and the scanned light beam is determined from the amount of change in the light receiving position. This relative angular velocity is input to the speed signal generation circuit as an acceleration/deceleration signal, and the output of the speed signal generation circuit is input to the motor drive circuit as a tracking speed signal.

Therefore, the motor drive circuit follows the tracking speed signal,
Each Y-axis pulse motor is driven to accelerate and decelerate the tracking speed of the scanning means so that the relative angular velocity becomes zero.

<Example> An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram showing an outline of a tracking device used in the present invention.

A fixed station 10 of a tracking device according to the present invention is constituted by a scanning means 100, a control section 400, and a retroreflector 200 provided on a moving body 20. Scanning means 100 and retroreflector 200
has the same configuration as the prior art, and detailed explanation thereof will be omitted. As shown in FIG. 2, the control section 400 has registers 403.4 on the input side of the control section 300 of the conventional device shown in FIG.
04.405.406, subtracters 407.408, and acceleration/deceleration discrimination circuits 409.410.

Other than the above, the configuration is the same as that of the control unit 300 of the conventional device.

Next, a method of controlling the tracking speed of a moving object using this tracking device will be explained.

The light beam L[l generated from the light beam generator 110 passes through the passage hole 131, is emitted into space, and is scanned.

When the scanned light beam LB enters the center of the retroreflector 200, it returns as a return beam RB in the same direction as the light beam LB and heads toward the passage hole 131. When tracking is complete, the light receiving position sensor 132 does not detect the return beam RB, or the light receiving position sensor 132 receives the feedback beam equally in all quadrants. However, moving object 2
When 0 attempts to deviate from the state of perfect tracking, the return beam I? B is removed from the passage hole 131 and the light receiving position sensor 13
The light is incident on one of the two light receiving elements.

Note that the position of the light receiving element of the light receiving position sensor 132 is determined in advance by coordinates, and is detected as a detection signal determined by the coordinates. For example, when the position of the light-receiving element is within the first quadrant, there is positive scratching in both the χ-axis and Y-axis directions, and the light-receiving position signal is transmitted to the scanning mechanism 12.
The rotation direction of 0, that is, the tracking direction signal is output as right and top. Further, when the light receiving position is the origin of the coordinates, both the light receiving position signals become zero, and the tracking direction signal is outputted as an atmosphere.

The detection signal of the light receiving position sensor 132 is input as a light receiving position signal to polarity determination circuits 401 and 402, and is output as a tracking direction signal. Further, the light receiving position signal is input to subtracters 407 and 408, and is also input to register 403.
．． 405. Then, a new light receiving position signal accompanying the movement of the mobile object 20 is registered in registers /103, 405.
, the previous old light receiving position signal is stored in register 4.
04.406.

The subtracters 407 and 408 erase the previous old light receiving position signal held in the register 403 and 405 from the new light receiving position signal, and output this absolute value as the amount of change in the light receiving position, and the acceleration/deceleration determining circuit 409 and 410 is input. Acceleration/deceleration determination circuits 409 and 410 perform acceleration when the amount of change in the light receiving position is positive, constant speed when it is zero, and deceleration when negative. Output a signal.

Next, speed signal generation circuits 413 and 414 operate the X-axis pulse motor 123 and the Y-axis pulse motor 1 based on the signals.
A tracking speed signal that accelerates or decelerates the rotation speed of 24 is output.

The x-axis and Y-axis motor drive circuits 415 and 416 drive the X-axis pulse motor 123 based on the tracking signal and tracking speed signal.
and Y-axis pulse motor 1241['J].

Further, when the moving body 20 stops, the tracking speed is reduced and the tracking operation is performed at the lowest tracking speed set in the minimum speed setting 2S411.412.

FIG. 3 is a block diagram of a control unit 500 showing a different embodiment, in which a light receiving direction sensor 133 is used as a light receiving detector 130.
This shows the case where . Regulation? 111 section 500 has a subtracter 501.5 on the input side of the control section 400 shown in FIG.
02 is added, and the other parts are the control unit 40.
Same as 0.

The light-receiving element signal detected by the light-receiving direction sensor 133 is sent to a subtracter 501 for each quadrant facing each other across the origin.
．． 502.

When the feedback beam RB deviates from the origin of the light receiving direction sensor 133, the subtracters 501 and 502 output the received light amount difference in the vertical and horizontal directions as a received light amount difference signal based on the light receiving signal of the light receiving direction sensor 133. When the feedback beam RB is received over two opposing quadrants of the light receiving direction sensor 133, the amount of deviation of the center of the feedback beam RB from the origin is proportional to the difference in the amount of received light. Therefore, by comparing the magnitudes of the received light quantity difference signals, it is possible to know the change in the light receiving position of the feedback beam RB. The received light amount difference signal from the subtracters 501 and 502 is sent to the control unit 40.
0, and the others are also operated by the control section 4.
00, detailed explanation thereof will be omitted.

FIG. 4 is an explanatory diagram of the operation of the light receiving direction sensor 133.
Figure (A) is a plan view of the light receiving position sensor 132, and Figure (B) is a graph showing the relationship between the amount of deviation and the tracking speed. FIG. 5 is an explanatory diagram of the operation of the light receiving direction sensor 1.33, (^) is a plan view, and (B) is a graph showing the relationship between the difference in the amount of received light and the tracking speed.

In FIG. 4(A), if the light receiving position of the feedback beam RB received by the light receiving position sensor 132 is P, and the amount of change in the light receiving position from the origin 0 is d, then as shown in FIG. 4(B), the light receiving position P Until it reaches the outer edge r of the light receiving position sensor 132, the amount of change d in the light receiving position gradually increases, so it is necessary to increase the tracking speed V to return to the origin 0. However, after passing the outer edge r, the feedback beam RB is not received and the light receiving position P
cannot be determined, so tracking will be stopped.

Therefore, the tracking speed ν suddenly changes to zero as shown by the broken line in FIG. Therefore, the operations of the X-axis pulse motor 123 and the Y-axis pulse motor 124 become unstable.

Therefore, in this case, it is necessary to provide a correction circuit that has the characteristics as shown by the solid line in FIG.

On the other hand, the light receiving direction sensor 133 detects the light receiving position change ld based on the difference in the amount of light received in each quadrant. For convenience of explanation below, the light receiving direction sensor 133 is the fifth
As shown in Figure (8), the explanation will be made assuming that the control is divided into two quadrants, upper and lower.

As shown in FIG. 5(A), the difference in the amount of received light is the return beam l
? When the light receiving position sequentially moves in the direction of the arrow shown in the figure from the position where the center of beam B is received at origin 0 (indicated by the broken line in the same figure), the difference in the amount of received light increases until the outer periphery of the feedback beam RB reaches position P1 where it touches the origin 0. is increasing.

The outer periphery of the feedback beam RB is the light receiving direction sensor 13.
The difference in the amount of received light is constant until the position inscribed in the outer edge r of 3)) 2 is reached. Further, when it changes from the inscribed position, it gradually remains and becomes zero at a position P3 circumscribed to the outer edge r. Note that in the light receiving direction sensor 133, the light receiving position change i
d and tracking speed ν are the same.

Therefore, after the tracking speed command signal also disappears, the tracking operation is stopped. Therefore, in the light-receiving direction sensor 133, the above-mentioned correction circuit is not required because the phenomenon and drastic changes as in the light-receiving position sensor 132 do not occur.

FIG. 6 is a schematic diagram of a control section 600 showing another embodiment, in which the control circuit of the control section 500 of FIG. 3 is simplified. That is, the register, subtracter, and acceleration/deceleration determination circuit are omitted from the control section 500.

In this embodiment, the speed signal is not obtained from the amount of change in the difference in the amount of light received by the light receiving direction sensor 133, but the distance of the light receiving position from the origin is directly changed into the speed signal.

FIG. 7 is a schematic explanatory diagram showing one embodiment of the light receiving direction sensor 133. One light receiving direction sensor 133 is disposed in each quadrant on a plane perpendicular to the optical axis, and a condenser lens 13 is provided in front of the light receiving direction sensor 133.
4 are provided. The condensing lens 134 is divided into four quadrants, and is configured such that the feedback beam RB passing through each quadrant is focused on the corresponding light receiving direction sensor 133. The center part of the condensing lens 134 is used for mounting the light beam generator 110 or the light beam LB.
A passage hole 131 is provided for passage of. The light receiving direction sensor 133 according to the present embodiment can detect the direction of the feedback beam RB in each quadrant, and can determine the direction of the moving object 20 based on this. Furthermore, the amount of change in the light receiving position of the origin and the feedback beam RB can be determined from the ratio of the light amounts of the feedback beam RB incident on a pair of quadrants facing each other with the origin in between. Therefore, compared to the light-receiving position sensor 132, the light-receiving detector can be constructed at a lower cost.

<Effects of the Invention> As explained above, the present invention detects the return beam by using a light receiving detector, and calculates the relative angular velocity between the moving body and the scanned light beam from the change in the light receiving position of the detected return beam.
Based on this, the tracking speed of the light beam is accelerated or decelerated. Therefore, the tracking speed of the light beam can be smoothly changed according to the speed of the moving object. In addition, stable tracking is possible even when the movement of a moving object suddenly changes, and the upper limit of tracking speed is higher than that of conventional models without acceleration/deceleration control.
Can be set.

[Brief explanation of the drawing]

1 to 7 are drawings according to the present invention, in which FIG. 1 is a schematic explanatory diagram of the tracking device, FIG. 2 is a block diagram of the control section, FIG. 4 is an explanatory diagram of the operation of the light receiving position sensor, and FIG. 6 is a block diagram of a control section showing a different embodiment from FIG. 3; FIG. 7 is a schematic explanatory diagram showing another embodiment of the light receiving direction sensor; FIG. 9 are schematic explanatory diagrams of a conventional tracking device. 100...Scanning means 110...Light beam generator 120...Scanning mechanism 132...Light receiving position sensor 133...Light receiving direction sensor 200...Retroreflector 400.500.600... Control unit patent applicant
Hitachi Kiden Kogyo Co., Ltd. Agent Patent Attorney Takaharu Ohnishi Figure 1 132 U4iF Kuchigosai Nza (B) Figure 7 Commissioner of the Patent Office Yoshi 1) Takeshi Moon 1. Display of the case Patent Application No. 111343 filed in 1988 2 Title of the invention Method for controlling the tracking speed of a moving object using a light beam 3 Person making the amendment Relationship to the case Patent applicant address 3-11 Shimosakabe, Amina City No. 1 Name: Hitachi Kiden Kogyo Co., Ltd. Representative: Yoshinobu Imamura 4, Agent address: 16-16, Tanimachi 5-32, Higashi-ku, Osaka, Subject of amendment: Column 7 of “Specification or Detailed Description of the Invention” Contents of correction - Correct the third line of page 3 of the specification cylinder, ``The optical axis of the generated light beam and the optical axis of 8'' to 1, so that each optical axis is 1. ■Y-axis pulse motor 124 that rotates the statement tube in the try-axis direction from page 3, line 8 to page 3, line 10.The Y-axis pulse motor 124 is attached to the Y-axis pulse motor 124 and rotates the frame 122 in the fy-axis direction. Correct the Y-axis pulse motor 124 and frame to j. (2) When the moving object changes suddenly, such as from page 6, line 14 of the specification cylinder to r-direction change, j is corrected to ``When the movement or movement direction of the moving object changes suddenly, such as when r-direction change, etc.''. ■Page 6 of the specification cylinder, line 18: “Even if the movement of the moving object suddenly changes,
is corrected to ``even if the motion or direction of movement of the moving object suddenly changes''. ■Correct "solder" in line 5 of page 11 of the specification to "judgment". ■Specification page 12 line 19 r Light receiving direction sensor 133j
r light receiving position sensor 132''. ■Page 14, line 10 of the specification: ``While reaching position P2, j is corrected to ``until position ffi P2 is reached.''

Claims (1)

[Claims] (1) A light beam generator, a scanning means that scans the light beam emitted from the light beam generator toward space, and a light reception detection that detects the return beam that is reflected and returned by a retroreflector provided on a moving object. In a method for tracking a moving object using a light beam, the method includes a controller that determines the moving direction of the moving object based on the detection output of the light-receiving detector and controls a scanning means, wherein the feedback detected by the light-receiving detector is The difference between the angular velocity of the moving object and the angular velocity of the scanned light beam as seen from the center of rotation of the light beam scanning means is determined from the change in the light receiving position of the beam, and the tracking speed of the scanning means is increased so that this angular velocity difference becomes zero. A method for controlling the tracking speed of a moving object using a light beam, characterized in that the speed is controlled to be decelerated.