Method for performing adaptive friction compensation in an actuator accounting for variation in friction characteristics of wave gear drive accompanying change in temperature

摘要

According to a method for performing adaptive friction compensation of an actuator including a wave gear drive, there is used as a friction compensation current applied to a motor drive current a static friction compensation current i_s when a motor shaft stops with a deviation, and a Coulomb friction compensation current i_c in other circumstances. The static friction compensation current i_s is obtained by adding a compensation amount i_sr of a monotonically increasing ramp function to a compensation amount i_ss of a step function, and a step-function compensation amount i_cs is used as the Coulomb friction compensation current i_c. Since the amount of friction compensation can be changed adaptively based on the data during positioning-control response, a motor shaft can be stabilized at a target angle without prominent accompanying vibration, even if the ambient temperature changes and the friction characteristics of the wave gear drive fluctuate.