Backlash compensation method for semi-closed-loop type servo control
AssigneeFanuc Corporation
InventorsTetsuaki Kato, Kokoro Hatanaka
Life of this patent
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Abstract
A method for properly compensating for a backlash between a servomotor and a machine moving part, such as a table, driven by the servomotor in a semi-closed-loop type control. In the semi-closed-loop type servo control, the force of a motor-driven table which acts on a motor is estimated by means of a disturbance observer, the side of the groove of a ball nut directly connected to the table, with which the ridge of the ball thread directly connected to the motor is in contact, is detected by the sign of the value of the estimated force, and the direction of backlash compensation is changed in accordance with the detected result.
Claims7
A backlash compensation method for semi-closed-loop type servo control, comprising the steps of:
- estimating a disturbance acting on a motor, using a disturbance observer, in response to receiving a torque command and a motor speed of the motor;
- and
- compensating for the backlash in accordance with the estimated disturbance, including changing a direction of backlash compensation in accordance with a sign of the estimated disturbance.
A method for compensating for backlash between a motor and a machine moving part in a semi-closed-loop type servo control, comprising the steps of:
- estimating a disturbance acting on the motor by the machine moving part based upon a torque command and motor speed of the motor;
- and
- determining a backlash compensation value based upon the estimated disturbance;
- and
- determining a sum of the backlash compensation value and a difference between a position command and a position feedback;
- transmitting the sum to a speed control loop, and determining the torque command from the speed control loop.
Dependencies are inferred from the claim text.