Patent ID: 6515442
Filing Date: 2003-02-04
Classification: G05B

Abstract:
A position controller comprising: a position control section in which a position. command and a detected movement position are inputted and from which a speed command is outputted; a speed control section in which the speed command and a motor speed are inputted and from which a torque command is outputted; a current control section which receives the torque command to perform amplification and outputs a current; a motor which rotates by being supplied with the current; a motor position detector which detects a rotational displacement of the shaft of the motor and outputs a motor position signal; a speed processor which receives the motor position signal and outputs a motor speed signal; and a movement position detector which detects the position of a movement section driven by the motor and outputs a movement position signal and provided with: a motor speed-control function which makes the speed command and the motor speed signal coincident by feedback control; and a motor position-control function which makes the position command and the movement position signal coincident by feedback control, wherein said position controller is provided with:a subtracter which subtracts the motor position signal from the movement position signal and outputs an angle-of-twist signal; a high-pass filter which outputs the angle-of-twist signal with its phase advanced, upon receiving the angle-of-twist signal; a low-pass filter in which the signal from the high-pass filter is inputted and which outputs the signal with only its high-frequency components eliminated; a coefficient multiplier which receives the signal from the low-pass filter, multiplies it by a torque corrective gain, and outputs a torque correction signal; a section for torque correction evaluation which varies the torque corrective gain based on a position deviation signal that is the difference between the position command and the movement position signal; and a subtracter which subtracts the torque correction signal from the torque command to produce a new torque command.