US 6,515,442 B1Granted

Position controller

AssigneeKabushiki Kaisha Yaskawa Denki

InventorsTadashi Okubo, Wennong Zhang, Yasuhiko Kaku, Kenichi Murata

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Abstract

To overcome the problem of a low frequency disturbance causing minute vibrations affecting response attributable to the difficulty of adaption to the phase of the vibrations, the present invention provides a position controller, which includes a subtracter for subtracting a motor position signal from a movement position signal to produce an angle-of-twist signal; a high-pass filter for advancing the phase of the angle-of-twist signal; a low pass filter for eliminating only high-frequency components of the signal received from the high-pass filter; a circuit for multiplying the signal from a low-pass filter by a torque-corrective gain to produce a torque-corrected signal; a torque correction evaluation section for varying the torque-corrective gain according to the position deviation signal that is the difference between a position command and the movement position signal; and a subtracter for combining the torque-corrective signal and the torque command to produce a new torque command.

Claims8

Dependent claims

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.

12 more elements

A position controller comprising:

a position control section in which a position command and a 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:
an observer which comprises a proportional operating means for performing proportional operation, an integration operating means for performing integration operation, an inertia model for multiplying by a gain ωs2 and inputting a torque command outputted from the speed control section, an adder which adds the output from the inertia model, the output from the proportional operating means, and the output from the integration operating means, an integrator which integrates the output from the adder and outputs an estimated speed, and a subtracter which inputs a differential signal, obtained by subtracting the estimated speed from the motor speed outputted from the speed processor, into the proportional operating means and the integration operating means and which produces the differential signal obtained by subtracting the estimated speed from the motor speed as an output;
a high-pass filter which receives the output signal from the observer and outputs the output signal with its phase advanced;
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 and 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.

12 more elements

Dependencies are inferred from the claim text.