JPS6375909A - Position controller - Google Patents

Abstract

PURPOSE:To obtain a superior rise characteristic, and non-oscillating response, by using an amplifier which adds a targeted position signal on an actuator directly, and a means which detects the speed and the position of a movable body, and amplifies and returns a detected signal. CONSTITUTION:In the titled device, the amplifier 14 which adds the targeted position signal on the actuator of the movable body 16 directly, and a control system including the means which detects the speed and the position of the movable body 16, and amplifies and returns the signals corresponding to the speed and the position, are used. Also, the amplifier 11 supplies a bias voltage to a piezoelectric element 15 to move the movable body 16 rapidly to the neighborhood of a targeted position, and an integrator 12 removes a quantity of aberration of the movable body 16, and also, holds the position of the movable body 16, that is a quantity of displacement of the piezoelectric element 15. Also, the piezoelectric element 15 acts as the actuator to drive the movable body 16. Thus, by adding the targeted position signal on the actuator of the movable body 16 directly through the amplifier 11, it is possible to realize the rise of a system at high speed, and by returning the signal, the oscillation of the movable body 16 can be suppressed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a position control device, and in particular to a device used in semiconductor exposure equipment and the like for precise positioning of semiconductor wafers, masks, etc. be.

[Prior Art] Conventionally, this type of device has been configured as shown in FIG. 3, for example. The device shown in the figure includes an integrator 1, a compensator 2 for correcting the servo characteristics of this device, an amplifier 3, a piezoelectric element 4 as a drive actuator, a movable body 5, and a position detector for detecting the position of the movable body 5. 6 and a subtracter 7.

In the apparatus shown in FIG. 3, a subtracter 7 generates an error signal between the target position signal of the movable body 5 and the signal detected by the position detector 6, and the error signal is added to the integrator 1. is moved, and the position of the movable body 5 is controlled so that the signal from the position detector 6 matches the target position signal.

[Problems to be Solved by the Invention] In this method, since the error signal is applied to the integrator 1, the transient characteristics of the movable body 5 are determined by the characteristics of the integrator 1.
When applying a target position signal, etc., there is a problem in that the rise of the displacement of the movable body 5 is significantly delayed due to the delay in the rise of the output of the integrator 1, as shown in FIG. In addition, in order to speed up the rise, there is a method of installing an amplifier 31 as shown in Fig. 5 to amplify and apply the input target position signal directly to the movable body. The inconvenience that the signal became vibrating as shown in FIG. 6 was eliminated.

SUMMARY OF THE INVENTION In view of the above-mentioned problems with the conventional type, an object of the present invention is to improve the start-up characteristics and shorten the positioning time when determining the position of a movable body in a position control device.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention includes an amplifier that directly applies a target position signal to an actuator of a movable body, and an amplifier that detects the speed and position of the movable body. A control system is used that includes means for amplifying and feeding back a signal corresponding to the signal.

In the above-mentioned means, a high-speed start-up can be achieved by applying the target position signal directly to the actuator of the movable body via an amplifier, and in particular, by feeding back a signal corresponding to the speed of the movable body, Vibration is suppressed and start-up characteristics are significantly improved.

[Example] The present invention will be described in detail below with reference to the drawings. FIG. 1 schematically shows a position control device according to an embodiment of the present invention. The device shown in the figure includes an amplifier 11 for amplifying the target position signal;
Integrator 12, adder/subtractor 13, amplifier 14. A piezoelectric element 15 as a drive actuator, a movable body 16, a position detector 17 for obtaining position information of the movable body, an amplifier 18 for amplifying the detected position signal, and a movable body for obtaining velocity information when the movable body is displaced. A speed detector 19, an amplifier 20 for amplifying the detected speed signal, an adder 21, and a subtracter 22
By o(3).

The amplifier 11 is an amplifier that serves to apply a bias voltage to the piezoelectric element 15 in order to quickly move the movable body 16 to the vicinity of the target position, and the integrator 12 eliminates the amount of positional deviation of the movable body 16 and 16, that is, the amount of displacement of the piezoelectric element 15. The amplifier 14 is for obtaining the voltage necessary to displace the piezoelectric element 15 in accordance with the position signal, and the piezoelectric element 15 acts as an actuator for driving the movable body 16.

In the apparatus shown in FIG. 1, when a target position input signal is applied, the input signal is quickly applied to the amplifier 14 by the amplifier 11, and is amplified by the amplifier 14 to displace the piezoelectric element 15 and rapidly move the movable body 16 to the vicinity of the target position. . At this time, the current position of the movable body 16 is detected by the position detector F, and the error between this current position and the target position is calculated by the subtractor 22.
The integrator 12 generates a signal for correcting this error. From the output signal of the integrator 12, etc., an adder 13 generates a signal with the amount of positional deviation corrected, and the position of the movable body 1δ is controlled in accordance with this signal.

A signal corresponding to the position of the movable body controlled in this manner, that is, a position signal, is generated by the position detector 17, and the position of the movable body 16 is feedback-controlled in accordance with this signal.

On the other hand, a signal for suppressing the vibrational movement of the movable body 16 is transmitted to each amplifier 20. By amplifying the signal by 18, adding it by adder 21, and feeding back this signal, it is possible to suppress the vibration of the movable body 16 and shorten the positioning time. In this way, it is possible to obtain a quick rise and non-oscillatory response characteristic as shown in FIG.

[Effects of the Invention] As explained above, according to the present invention, an amplifier that directly applies a target position signal to an actuator and a means for detecting the speed and position of a movable body, amplifying the detected signal, and feeding it back are used. By doing so, it is possible to obtain a non-vibratory response with good rise characteristics, and to shorten the positioning time.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram schematically showing a position control device according to an embodiment of the present invention, FIG. 2 is a waveform diagram showing a step response of the movable body 16 in the device of FIG. 1, and FIG. 3 is a conventional type 4 is a waveform diagram showing the step response of the movable body 5 in the position control device of FIG. 3, and FIG. 5 is a block circuit diagram showing the configuration of another conventional position control device. FIG. 6 is a waveform diagram showing a step response of the movable body 37 in the position control device shown in FIG. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Satoshi Ito Figure 1 Figure 2

Claims (1)

[Claims] 1. A displacement command type actuator that drives a movable body, an amplifier that provides a signal to the actuator to move the movable body near a target position, and a position detector that detects the current position of the movable body. the actuator, an integrator for integrating a signal corresponding to the deviation between the target position and the current position to generate the actuator drive signal, and a speed detector for extracting a speed signal corresponding to the moving speed of the movable body. A position control device characterized in that vibration of the movable body is suppressed by also feeding back the speed signal component to the actuator. 2. The position control device according to claim 1, wherein the speed detector generates a speed signal by differentiating a position detection signal of the movable body.