Servo motor controller having self-measuring function and self-monitoring function of mechanical stiffness

摘要

A servo motor controller includes a speed command generating unit for generating a speed command value of the servo motor, a speed detecting unit that detects a speed of the servo motor, a torque command generating unit for generating a torque command value, a sine wave generating unit for generating a sinusoidal disturbance value, a frequency response calculating unit for calculating a frequency response when the sinusoidal disturbance value has been input to a speed control loop, a resonance frequency detecting unit for detecting a resonance frequency at which a gain is maximized, a resonance frequency storing unit for storing the resonance frequency, at least one filter for attenuating a specific frequency band component included in the torque command value, and a resonance frequency comparing unit for measuring stiffness of a machine tool based on the resonance frequency and adjusts the filter with respect to the resonance frequency.

主权项

1. A controller that controls a servo motor for driving a machine tool, comprising:
a speed command generating unit configured to generate a speed command value of the servo motor; a speed detecting unit configured to detect a speed of the servo motor; a torque command generating unit configured to generate a torque command value of the servo motor on a basis of the speed command value and the detected speed; a sine wave generating unit configured to generate a sinusoidal disturbance value; a frequency response calculating unit configured to add the sinusoidal disturbance value generated by the sine wave generating unit to the speed command value, thereby calculating a frequency response on a basis of output from a speed control loop when the sinusoidal disturbance value has been input to the speed control loop including the torque command generating unit and the speed detecting unit; a resonance frequency detecting unit configured to detect a resonance frequency which is a frequency at which a gain of the calculated frequency response is maximized; a resonance frequency storing unit configured to store the resonance frequency detected by the resonance frequency detecting unit; at least one filter that attenuates a specific frequency band component included in the torque command value; and a resonance frequency comparing unit configured to measure stiffness of a machine tool on a basis of the resonance frequency stored in the resonance frequency storing unit, and adjusts the filter with respect to the resonance frequency.