Consider the friction characteristics of the transmission change gear mechanism changes with temperature fluctuation of the friction compensation method is suitable for the actuator of

According to a method for performing adaptive friction compensation of an actuator (2) including a wave gear drive (1), there is used as a friction compensation current applied to a motor drive current a static friction compensation current is when a motor shaft stops with a deviation, and a Coulomb friction compensation current ic in other circumstances. The static friction compensation current is is obtained by adding a compensation amount isr of a monotonically increasing ramp function to a compensation amount iss of a step function, and a step-function compensation amount ics is used as the Coulomb friction compensation current ic. Since the amount of friction compensation can be changed adaptively based on the data during positioning-control response, a motor shaft (6) 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 (1) fluctuate.