Joint torque control for two-inertia system with encoders on drive and load sides

In the past 20 years, control methods for two-inertia systems have gradually changed from semi-closed control to full-closed control in order to achieve higher precision positioning. Though there is a trend toward the expansion of the use of load-side encoders in the industry, we can hardly say that control methods using load-side information are sufficiently studied. This paper proposes a novel joint torque control method for a two-inertia system using a high-resolution encoder on the load side. The proposed method enables us to control joint torque precisely considering nonlinear elements such as backlash, lost motion etc. Simulation and experimental results demonstrate that the good performance can be obtained by the proposed method.