Compensation by exact linearization method for nonlinear components in positioning device with harmonic drive gearings

Abstract

This paper presents a novel compensation approach for nonlinear properties in harmonic drive gearings, in order to improve the performance deterioration in the static/dynamic positioning caused by the nonlinear components in mechanism. In the compensation, a modified exact linearization method is applied in the model-based feedforward control manner, where a two-mass plant system with nonlinear components, i.e. friction, stiffness, and angular transmission error of the gearing, is mathematically modeled to ensure the linearization. The proposed approach has been adopted to a positioning controller and been verified by numerical simulations and experiments using a prototype of positioning device with harmonic drive gearing.