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Actuator, actuator control method, and actuator control program

Foreign code F120006129
File No. S2008-0565
Posted date Jan 6, 2012
Country United States of America
Application number 91751310
Gazette No. 20110120296
Gazette No. 8146481
Date of filing Nov 2, 2010
Gazette Date May 26, 2011
Gazette Date Apr 3, 2012
Priority data
  • P2008-120785 (May 2, 2008) JP
  • P2008-204612 (Aug 7, 2008) JP
  • 2009WO-JP58619 (May 7, 2009) WO
Title Actuator, actuator control method, and actuator control program
Abstract (US8146481)
An actuator in which overshooting has been reduced is provided.
A cylinder is divided by a piston to provide first and second chambers, and first and second control valves 41, 43, which adjust fluid pressure supply to respective chambers in a non-step manner, and first and second discharge valves 42, 44, which control outflow of fluid from the first and second chambers, are provided.
A first control device carries out feedback control of pressure to be supplied to the first or second chamber such that a difference between a target position of the piston and a detected position of the piston becomes smaller.
A second control device carries out differential-preceding PD control to bias pressure to be commonly supplied to the first and second chambers such that the difference between the target position of the piston and the detected position of the piston becomes smaller.
Scope of claims [claim1]
1. An actuator having a piston slidably arranged in a cylinder and dividing the cylinder into a first chamber and a second chamber, and controlling pressures of gaseous or liquid fluids in the first and second chambers to control a position of the piston in a sliding direction while changing bias pressure common to the gaseous or liquid fluids in the first and the second chambers to change rigidity caused to the piston by the bias pressure, the actuator comprising: first and second control valves arranged between a fluid pressure source and the first and second chambers and configured to adjust fluid pressure supply to the first and second chambers in a non-step manner;
first and second discharge valves configured to allow the fluid in the first and second chambers to flow in a discharge direction from the first and second chambers toward the atmosphere or low pressure source side;
a first control device carrying out feedback control of pressure to be supplied to the first or second chamber such that a difference between a target position of the piston and a detected position of the piston becomes smaller; and
a second control device carrying out feedback control of bias pressure to be commonly supplied to the first and second chambers such that the difference between the target position of the piston and the detected position of the piston becomes the smallest,
wherein each of the first control device and the second control device serves as a control device for controlling either one of the first control valve and the second control valve.
[claim2]
9. A method of controlling an actuator having a piston slidably arranged in a cylinder and dividing the cylinder into a first chamber and a second chamber, the method controlling pressure of gaseous or liquid fluid in the first and second chambers to control a position of the piston in a sliding direction while changing bias pressure common to the gaseous or liquid fluids in the first and the second chambers to change rigidity caused to the piston by the bias pressure, the actuator comprising first and second control valves arranged between a fluid pressure source and the first and second chambers and configured to adjust fluid pressure supply to the first and second chambers in a non-step manner; and first and second discharge valves configured to allow the fluid in the first and second chambers to flow in a discharge direction from the first and second chambers toward the atmosphere or low pressure source side, and the method comprising steps of: carrying out feedback control of pressure to be supplied to the first or second chamber such that that a difference between a target position of the piston and a detected position of the piston becomes smaller; and
carrying out feedback control of bias pressure to be commonly supplied to the first and second chambers such that the difference between the target position of the piston and the detected position of the piston becomes the smallest,
wherein each of the steps of feedback control serves as controlling either one of the first control valve and the second control valve.
[claim3]
2. The actuator according to claim 1, wherein the second control device carries out the feedback control according to differential-preceding PD control such that a difference between a target position of the piston and a detected position of the piston becomes smaller.
[claim4]
3. The actuator according to claim 1, wherein when the target position of the piston is given to the first and second control devices, the first control device sets a gain enabling high responsiveness causing overshooting, and the second control device gradually increases a proportional gain in carrying out the feedback control from an initial value to negate the overshooting and adjusts the proportional gain by increasing or decreasing a differential gain in carrying out the feedback control.
[claim5]
4. The actuator according to claim 3, wherein an initial value of the differential gain which is set by the second control device is about 1/100 of the initial value of the proportional gain which is set by the second control device.
[claim6]
5. The actuator according to claim 1, wherein either one of the first control valve and the second control valve is controlled by the first control device, and both of the first control valve and the second control valve are controlled by the second control device.
[claim7]
6. The actuator according to claim 1, wherein either one of the first control valve and the second control valve is controlled by the first control device and the second control device, and the other one of the first control valve and the second control valve is controlled such that predetermined pressure is given to a corresponding one of the first and second chambers.
[claim8]
7. The actuator according to claim 1, wherein when either one of the first control valve and the second control valve is controlled by the first control device and the other one of the first control valve and the second control valve is controlled by the second control device, individually set gains for feedback control are used.
[claim9]
8. The actuator according to claim 1, wherein both the first control device and the second control device are individually provided for controlling the first control valve and the second control valve, and control is carried out using the gains for feedback control.
[claim10]
10. A computer program which stores computer program instructions which when executed by a computer performs steps of a method of controlling an actuator having a piston slidably arranged in a cylinder and dividing the cylinder into a first chamber and a second chamber, the method controlling pressure of gaseous or liquid fluid in the first and second chambers to control a position of the piston in a sliding direction while changing bias pressure common to the gaseous or liquid fluids in the first and the second chambers to change rigidity caused to the piston by the bias pressure, the actuator comprising first and second control valves arranged between a fluid pressure source and the first and second chambers and configured to adjust fluid pressure supply to the first and second chambers in a non-step manner; and first and second discharge valves configured to allow the fluid in the first and second chambers to flow in a discharge direction from the first and second chambers toward the atmosphere or low pressure source side, and the method comprising steps of:
carrying out feedback control of pressure to be supplied to the first or second chamber such that that a difference between a target position of the piston and a detected position of the piston becomes smaller; and
carrying out feedback control of bias pressure to be commonly supplied to the first and second chambers such that the difference between the target position of the piston and the detected position of the piston becomes the smallest,
wherein each of the steps of feedback control serves as controlling either one of the first control valve and the second control valve.
  • Inventor, and Inventor/Applicant
  • HOSHINO KIYOSHI
  • WERAGALA DON GAYAN KRISHANTHA
  • UNIVERSITY OF TSUKUBA
IPC(International Patent Classification)
U.S. Cl./(Sub)
  • F15B021/08
  • R15B211/305H10B
  • R15B211/630B50
  • R15B211/665L
  • R15B211/705B20
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