JPH03202907A - Positioner - Google Patents

Abstract

PURPOSE:To attain highly precise positioning through the use of one position detection sensor by providing a means to position a body to be positioned to a targeted position while supplying a move control signal which every finely moves a fine moving element moving finely a body to be positioned to the fine moving element. CONSTITUTION:A coarse movement/fine movement control means operates a coarse movement driving device 3 and the fine movement element 9 in accordance with a difference between the detection position of the positioned body 1 by position detection sensors 10-12 and the targeted position, and the positioned body 1 moves toward the targeted position. Then, an extremely fine movement means 25 is used to supply the movement control signal to the fine movement element 9, the positioned body 1 extremely finely moves and it is positioned at the targeted position. Thus, highly precise positioning is attained by using one position detection sensor.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement of a positioning device that performs positioning by coarse and fine movements.

(Prior Art) There are various techniques for positioning an object to be positioned at a target position, among which there is a technique called dual control that uses a coarse movement device and a fine movement device. In this dual control, the object to be positioned is moved toward a target position by a coarse movement device, the coarse movement device is then stopped, and then the object to be positioned is finely moved by a fine movement device to position it at the target position. In this case, the coarse movement device detects the position of the object to be positioned using a position detection sensor and feeds it back to move the object to be positioned, and the fine movement device detects the position of the object to be positioned using the position detection sensor of the coarse movement device. is detected by another position detection sensor and fed back to move the object to be positioned.

(Problems to be Solved by the Invention) As described above, in dual control, separate position detection sensors must be used for coarse movement and fine movement, which complicates the configuration. As a result, more accurate positioning is currently required.

Therefore, an object of the present invention is to provide a positioning device that can perform more accurate positioning using one position detection sensor.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a coarse movement drive mechanism for coarsely moving a positioning object, a fine movement element for finely moving the positioning object, and detecting the position of the positioning object. Either one of the coarse movement drive mechanism and the fine movement element is operated according to the difference between the position detected by the position detection sensor and the target position, and the coarse movement drive mechanism and the fine movement element are operated together. This is a positioning device that attempts to achieve the above object by including a coarse movement/fine movement control means and a very fine movement means that applies a movement control signal to the fine movement element to move the fine movement element very finely to position the object to be positioned at a target position.

(Function) By providing such a means, the coarse and fine movement control means can control either the coarse movement drive mechanism or the fine movement element according to the difference between the detected position of the object to be positioned by the position detection sensor and the target position. One of them is activated, and both the coarse movement drive mechanism and the fine movement element are activated, and the object to be positioned moves toward the target position.

Then, a movement control signal is supplied to the fine movement element by the fine movement means, and the object to be positioned is moved very finely to be positioned at the target position.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of the positioning device. This positioning device positions a reflecting mirror 1, and a friction drive mechanism 3 is provided on a support base 2.

This friction drive mechanism 3 is provided with a static pressure bearing 4, and a drive rod 5 is supported by this static pressure bearing 4. A slider 6 is connected to the tip of the drive rod 5 so as to respond to the drive rod 5. The slider 6 is supported by a hydrostatic bearing 8 with respect to the guide body 7, and is configured to move along the guide body 7 in the direction of arrow (A). A piezoelectric element 9 is provided on this slider 6, and the reflecting mirror 1 is provided on this piezoelectric element 9.

Further, a laser oscillator 10 as a laser length measurement system is provided on the support base 2, and a laser beam outputted from the laser oscillator 10 passes through an interferometer 11 and is irradiated onto the reflecting mirror 1. .

Because of this reflecting mirror 1, the reflected laser light enters the interferometer 11 again to obtain interference light.

A receiver 12 is provided on the support base 2, and this receiver 12 converts the interference light obtained by the interferometer 11 into an electrical signal and outputs the electrical signal.

However, the electrical output of this receiver 12 is
This is the output of the l-length system. Note that the friction drive mechanism 3 and the laser oscillator 10 are drive-controlled by a main controller 13.

On the other hand, a laser controller 20 is provided, and this laser controller 20 includes a coarse movement controller 20a and a fine movement controller 20b. The coarse movement controller 20a has a function of receiving an electric signal from the receiver 12, determining the position of the reflecting mirror 1, and outputting a coarse movement control signal according to the deviation between this position and the target position.

This coarse motion control signal is sent to the friction drive mechanism 3 through the friction drive amplifier 21. Also, fine movement controller 2
0b has a function of receiving an electric signal from the receiver 12, determining the position of the reflecting mirror 1, and outputting a fine movement control signal according to the deviation between this position and the target position. This coarse movement control signal is transmitted to the piezoelectric element amplifier 22 and the changeover switch 23.
is sent to the piezoelectric element 9 through. By the way, the laser controller 20 has a function of moving the anti-at mirror 1 by alternately operating the coarse movement controller 20a and the fine movement controller 20b. That is, first,
A voltage is applied to the piezoelectric element 9 to move the reflecting mirror 1 by, for example, a stroke X, and then the friction drive mechanism 3 is activated to move the reflecting mirror 1 in the same direction by the same stroke X. The voltage application is cut off to return the piezoelectric element 9 to its original state. As a result, the reflecting mirror 1 moves by the stroke X. Apply voltage again to the piezoelectric element 9 to move the opposite mirror 1 by, for example, a stroke X, then activate the friction drive mechanism 3 to move the reflecting mirror 1 in the same direction by the same stroke X, and at the same time move the opposite mirror 1 to the piezoelectric element 9. Cut off the voltage application. As a result, the reflecting mirror 1 moves by a stroke of 2x. Thereafter, the friction drive mechanism 3 and the piezoelectric elements are operated alternately in the same manner to move the reflecting mirror 1. Note that the laser controller 20 operates upon receiving a command W from the main controller 13.

The main controller 13 has a function of issuing a command to move the reflecting mirror 1 from a stroke that is the same as the detection resolution (minimum stroke that can be measured) of the laser length measurement system to a stroke that is 1/28th of this stroke. ing. This command is sent to the ultra-fine positioning circuit 25 through the interface 24.

The micro-movement positioning circuit 25 receives a command from the main controller 13 and a voltage applied to the piezoelectric element 9 from the piezoelectric element amplifier 22, and controls the piezoelectric element 9 in order to micro-move the reflecting mirror 1 at the above-mentioned resolution. It has a function of interpolating the applied voltage.

For example, when the reflection mirror 1 is at position X2, the voltage applied to the piezoelectric element 9 is v2, and when the reflection mirror 1 is at position x3, the voltage applied to the piezoelectric element 9 is
When the voltage applied to the piezoelectric element 9 is V, the voltage V applied to the piezoelectric element 9 to move it to the intermediate position X6.5 between the positions x2 and
11. becomes V3.5-V2 + (V3-V2)/2.

Therefore, if (V3 V2) is the resolution of the laser length measurement system, positioning will be performed with a resolution that is half this. The specific configuration is as shown in FIG. That is, an 8-bit A/D converter 25a (output terminal Do"'D?) and a 16-bit D/A converter 25b (input terminal Do=D+s) are provided.The A/D converter 25a has a piezoelectric The voltage applied to the piezoelectric element 9 is manually applied through the element amplifier 22, and its A
The /D conversion output is sent to the upper 8 bits (input terminals D8 to D15) of the D/A converter 25t>. Further, commands from the main controller 13 that pass through the interface 24 are sent to the lower 8 bits (input terminal D) of the D/A converter 25b.
o=D7). However, the D/A converter 25b converts the signals input to the upper 8 bits and the lower 8 bits into an analog signal and outputs the D/A converter. For example, reflective mirror 1
is position X.

When the output terminal of the A/D converter 25a is positioned at - When D7 is at a low level and the reflecting mirror 1 is positioned at position x6, the output terminal Do of the A/D converter 25a is at a high level;
-D is at a low level, and on the other hand, when the A/D converter 25b is positioned at the same position X, a low level is input to each input terminal D0 to DI5 of the A/D converter 25b, and the position Ii! Xs
When the input terminals of the A/D converter 25b are positioned at A low level is input to -D7, a high level is input to input terminal D8, and each input terminal is input to ~D8. A low level is input to the input terminal. In this state, the input terminal of the D/A converter is input from the main controller 13. When a command is issued to set the voltage to high level, the applied voltage va va-(V6-Vs)/28 is D/A converted and output from the D/A converter 25b. Therefore, the piezoelectric element 9 receives the applied voltage va and is displaced by (X6 X5)/28.

Furthermore, when the main controller 13 issues a command to set the input terminal D1 of the D/A converter to a high level in the above state, the D/A converter
The applied voltage vb vb=(V6-vs)/2' is D/A converted and outputted from the A converter 25b. Therefore, the piezoelectric element 9 will be displaced by Cxb xs)/2' in response to the applied voltage vb.

Furthermore, when the main controller 13 issues a command to set the input terminal D7 of the D/A converter to a high level in the above state, the piezoelectric element 9 will be displaced by (X6 xs)/2 in the same manner as above.

Accordingly, the piezoelectric rope 9 is positioned with a resolution that is 1/28th of the resolution of the laser length measurement system in response to a command issued from the main controller 13.

The changeover switch 23 receives a command S from the main controller 13.
In the case of coarse movement and fine movement, it is connected to terminal a, and in the case of very fine movement, it is switched to terminal A.

Next, the operation of the apparatus configured as described above will be explained.

The main control device 13 issues an operating command to the friction drive mechanism 3, an operating command to the laser oscillator 10, an operating command W to the coarse controller 20a, and a command S to switch the changeover switch 23 to terminal a. emits. As a result, the friction drive mechanism 3 becomes driveable and the laser oscillator 10 emits laser light. This laser light passes through an interferometer 11 and is irradiated onto a reflecting mirror 1.
The reflected laser light enters the interferometer 11 again.

In this interferometer 11, interference light is generated by the laser light from the laser oscillator 10 and the reflected laser light from the reflection mirror 1. Receiver 12 receives this interference light, converts it into an electrical signal, and outputs it.

The coarse movement controller 20a receives the electrical signal from the receiver 12, determines the position of the reflecting mirror 1, and sends out a coarse movement control signal to eliminate the deviation between this position and the target position. This coarse motion control signal is amplified by the friction drive amplifier and sent to the friction drive mechanism 3. This friction drive mechanism 3 receives a coarse movement control signal and moves the drive rod 5 in the direction of arrow (A). The slider 6 moves in response to this drive rod, and the reflecting mirror 1 moves toward the target position accordingly. When the reflecting mirror 1 approaches the target position due to this coarse movement, the main controller 13 stops the operation of the coarse movement controller 20a and activates the fine movement controller 20b.

The fine movement controller 20b receives the electric signal from the receiver 12, determines the position of the reflecting mirror 1, and sends out a fine movement control signal to eliminate the deviation between this position and the target position. This fine movement control signal is amplified by the piezoelectric element amplifier 22 and applied to the piezoelectric element 9 through the changeover switch 23. This piezoelectric element 9 is displaced by application of a fine movement control signal (voltage signal), and moves the reflecting mirror 1 by a minute distance.

Thereby, the reflecting mirror 1 is positioned with respect to the target position with an accuracy corresponding to the resolution of the laser length measurement system.

By the way, after the movement by coarse movement is completed, not only fine movement but also coarse movement and fine movement may be operated alternately. In this case, the main controller 13 first operates the fine movement controller 20b. The fine movement controller 20b increases the voltage applied to the piezoelectric element 9 in steps as shown in FIG. 3, and sends out a fine movement control signal of the applied voltage that produces the maximum displacement F. Then, when the piezoelectric element 9 reaches the maximum displacement F, the fine movement controller 20b makes the voltage applied to the piezoelectric element 9 zero. At the same time, the coarse movement controller 20a sends out a coarse movement control signal to move the piezoelectric element 9 by the displacement F in the same direction as the displacement F.

Thereby, the coarse movement drive mechanism 3 moves the drive rod 5 by the displacement F. As a result, the reflecting mirror l has moved by a displacement F. Next, a stepwise increasing voltage is applied to the piezoelectric element 9 again, and the maximum displacement F is generated. Then, when the piezoelectric element 9 reaches the maximum displacement F, the fine movement controller 20b again sets the voltage applied to the voltage element 9 to zero, and at the same time, the friction drive mechanism 3 causes the reflection mirror 1 to move to the displacement F.
will be moved only. As a result, the reflecting mirror 1 moves by a displacement of 2F. Thereafter, fine movement and coarse movement are similarly performed alternately, and the reflecting mirror 1 is positioned with respect to the target position with an accuracy corresponding to the resolution of the laser length measurement system.

Next, the main controller 13 issues a switching command to the changeover switch 23. As a result, the selector switch 23 is switched to the terminal. Furthermore, the main controller 13 is a laser controller 2
0 and issues a command to the ultra-fine positioning circuit 25. This command is the difference between the current position of the reflecting mirror 1 and the target position, and is a value indicating a stroke with a resolution of 1/28 of the resolution of the laser length measurement system, as described above. For example, when the reflecting mirror 1 is at position X, the difference from this position to the target position is (x b x
5) If it is /2', the main controller 13 issues a command to set the input terminal D1 of the D/A converter to a high level.

Upon receiving this command, the D/A converter 25b applies an applied voltage v
b vb-(V6-V5)/2' is output. As a result, the piezoelectric cord 9 receives the applied voltage vb and is displaced by (X6 Xs)/2', and the reflecting mirror 1 is positioned at the target position.

In this way, in the above-mentioned embodiment, the friction drive mechanism 3 is operated according to the difference between the position of the reflecting mirror 1 detected by the position detection sensor and the target position, and then the piezoelectric element 9 is displaced. The friction drive mechanism 3 and the piezoelectric cable 9 are operated alternately to move the reflecting mirror 1, and then the reflecting mirror 1 is positioned at the target position through the micro-movement positioning circuit 25, so that one laser length measurement system can be used. Using this, the position of the reflecting mirror 1 can be determined with an accuracy of 1/28 of the resolution of the laser 8Fl length system. Further, since only the ultra-fine positioning circuit 25 is added, the configuration is simple.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from its scope. for example,
For the coarse movement, other mechanisms other than the friction drive mechanism may be used, and for the fine movement, an electrostrictive element or a magnetostrictive element may be used.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a positioning device that can perform more accurate positioning using one position detection sensor.

[Brief explanation of drawings]

1 to 3 are diagrams for explaining one embodiment of a positioning device according to the present invention, in which FIG. 1 is a configuration diagram, and FIG. 2 is a specific configuration diagram of a micro-movement positioning circuit, FIG. 3 is a diagram showing displacement when coarse movement and fine movement are performed alternately. DESCRIPTION OF SYMBOLS 1... Reflection mirror 2... Support stand, 3... Friction drive mechanism, 5... Drive rod, 6... Slider, 9...
... Piezoelectric element, 10... Laser oscillator, 11... Interferometer, 12... Receiver, 13... Main controller, 2
0... Laser controller, 20a... Controller for coarse movement, 20b... Controller for fine movement, 21...
・Amplifier for friction drive, 22...Amplifier for piezoelectric element, 2
3... Selector switch, 24... Interface,
25... Ultra-fine positioning circuit. Figure 2

Claims (1)

[Claims] A coarse movement drive mechanism that coarsely moves the object to be positioned, a fine movement element that moves the object to be positioned finely, a position detection sensor that detects the position of the object to be positioned, and a position detected by the position detection sensor and a target position. coarse and fine movement control means for operating one of the coarse movement drive mechanism and the fine movement element and for operating both the coarse movement drive mechanism and the fine movement element according to the difference between the coarse and fine movement elements; 1. A positioning device comprising: micro-movement means for positioning the object to be positioned at the target position by applying a movement control signal for micro-movement to the fine movement element.