Backlash Compensation of Reduction Gears by Twin Motor Cooperative Control (1st Report)

—Study on Compensation Method using Backlash Model—

Abstract

Backlash of reduction gear produces troubles in case of positioning of robots and NC machine tools. It sometimes causes deterioration of positioning accuracy and self-excited vibration. To overcome such troubles special reducers, for example the harmonic drive or RV drive. But such reducers have special structure, so the cost of the reducer becomes expensive in robot or NC system. In this study, a new control method, named twin motor system is studied, that is two servo motors are controlled cooperatively and compensate the backlash of reduction gear.
In this report, a basic simulation model of backlash model is proposed and conditions of twin motor pinion and output gear is analyzed. Experimental results of servo stiffness improvement and 1 pulse positioning accuracy are reported.