Position control system

• US 5,568,032 A
• Filed: 05/24/1995
• Issued: 10/22/1996
• Est. Priority Date: 05/24/1994
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Wakui, Shinji
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US08/448,660
• Time in Patent Office: 517 Days
• Field of Search: 318/560, 318/568.22, 318/575, 318/590, 318/592, 318/601, 318/602, 318/604, 318/605, 318/609, 318/610, 318/611, 318/632, 318/649, 318/651, 318/652, 318/678, 310/311
• US Class Current: 318/632
• CPC Class Codes: B23Q 15/22 Control or regulation of position of tool or workpiece
• CPC Class Codes: G05B 2219/41182 PI precompensation for position loop
• CPC Class Codes: G05B 2219/41195 Cross coupled feedback, position change one axis effects control of other
• CPC Class Codes: G05B 2219/41344 Piezo, electrostrictive linear drive
• CPC Class Codes: G05B 2219/49267 Three linear actuators to position vertically and rotate horizontally
• CPC Class Codes: G05B 2219/50046 Control of level, horizontal, inclination of workholder, slide

Abstract

A position control system which includes a plurality of actuators for moving an object, a plurality of sensors for detecting the state of the object, a first circuit for extracting a state signal, in each of different kinetic modes related to the object, from outputs of the sensors, a compensating circuit for compensating for the state signals in the respective kinetic modes, a second circuit for distributing an output of the compensating circuit and for providing drive signals for the actuators in accordance therewith, and a driver for driving the actuators in response to the drive signals.

Claims

1. A position control system, comprising:

a plurality of actuators for moving an object;

a plurality of sensors for detecting the state of the object;

a first circuit for extracting a state signal, in each of different kinetic modes related to the object, from outputs of said sensors;

a compensating circuit for compensating for the state signals in the respective kinetic modes;

a second circuit for distributing an output of said compensating circuit and for providing drive signals for said actuators in accordance therewith; and

a driver for driving said actuators in response to the drive signals.

2. A system according to claim 1, wherein at least one of said sensors includes a position sensor.

3. A system according to claim 1, wherein at least one of said sensors includes an acceleration sensor.

4. A system according to claim 1, wherein the object comprises a flat substrate.

5. A system according to claim 4, wherein the number of the kinetic modes is three and wherein the kinetic modes include one translational motion in a vertical direction along the surface of the object and rotational motion in two directions along the surface of the object.

6. A system according to claim 1, wherein the number of said actuators is three, and wherein the number of said sensors is three.

7. A system according to claim 1, wherein said compensating circuit includes a circuit for producing a differential signal between the state signal in each of the kinetic modes and a command.

8. A system according to claim 7, wherein said compensating circuit includes a circuit for performing gain adjustment to an output of an amplifier for amplifying the differential signal.

9. A system according to claim 7, wherein said compensating circuit includes a proportional integration operation compensator for performing proportional integration and gain adjustment to an output of an amplifier for amplifying the differential signal.

10. A system according to claim 1, wherein said driver includes a power amplifier.