Patent ID: 8296089
Filing Date: 2012-10-23
Classification: F16H,G05B,H02P

Abstract:
1. A method for compensating for an angular transmission error of a wave gear device in cases in which an actuator for reducing the speed of output rotation of a motor via the wave gear device and transmitting the output rotation to a load device is driven and controlled by a processor arranged as a semi-closed loop control for controlling the position of the load shaft of the load device on the basis of the detected position of the motor shaft of the motor; comprising: determining, by the processor, a motor shaft synchronous component θSync occurring in synchrony with a motor position θm, which is a rotational position of the motor shaft, by Formula (A), the motor shaft synchronous component being an angular transmission error component that occurs in synchrony with the relative rotation of each constituent element of the wave gear device, and the motor shaft synchronous component being present even in cases in which torque is not applied to the wave gear device representing the actuator as a two-inertia model constructed from a motor-side inertia body including the rotor of the motor and the input shaft of the wave gear device, and a load-side inertia body including the output shaft of the wave gear device and the load device; applying the motor shaft synchronous component θSync (θm) calculated from the motor position θm as twisting between the motor-side inertia body and the load-side inertia body; considering the motor shaft synchronous component θSync (θm) to be an oscillation source; correcting a motor current command iref by a compensation current command icomp determined by Formula (B) where Ci(s) is a transfer function, and θ″Sync is the second-order differential of the motor shaft synchronous component; and, correcting the motor position command r by the motor position correction signal θcomp determined by Formula (C) whereby compensating for the effect of the motor shaft synchronous component θSync (θm) on the load position θl, which is the rotational position of the load shaft.