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Actuator, actuator control method, and actuator control program

外国特許コード	F120006129
整理番号	S2008-0565
掲載日	2012年1月6日
出願国	アメリカ合衆国
出願番号	91751310
公報番号	20110120296
公報番号	8146481
出願日	平成22年11月2日(2010.11.2)
公報発行日	平成23年5月26日(2011.5.26)
公報発行日	平成24年4月3日(2012.4.3)
優先権データ	特願2008-120785 (2008.5.2) JP 特願2008-204612 (2008.8.7) JP 2009WO-JP58619 (2009.5.7) WO
発明の名称（英語）	Actuator, actuator control method, and actuator control program
発明の概要（英語）	(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.
特許請求の範囲（英語）	[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.
発明者/出願人（英語）	HOSHINO KIYOSHI WERAGALA DON GAYAN KRISHANTHA UNIVERSITY OF TSUKUBA
国際特許分類(IPC)	F15B 9/09 電気的制御手段をもつもの G05B 19/19 位置決めまたは輪郭制御系に特徴があるもの，例．１つのプログラムされた点から他の点に位置を制御する，またはプログラムされた連続経路に沿って運動を制御するもの
米国特許分類/主・副	F15B021/08 R15B211/305H10B R15B211/630B50 R15B211/665L R15B211/705B20