Load torque control using variable spring constant model for shaft torsion phenomena of motor with built-in double encoders and reduction gear.

Abstract

The purpose of this project is to design a load torque controller driven by a servo motor with reduction gear. A low-rigidity coupling is inserted between the motor output shaft and the shaft on the load side, and the motor side angle and the load side angle can be measured with encoders. The comparative method using a linear spring constant model for the shaft torsion phenomena caused load torque estimation errors partially. Therefore, I modeled the nonlinearity of the spring constant of the coupling. Simulation confirmed the nonlinear spring constant model identified in the experiment suppressed the tracking error to less than 0.1N.