Rate loop control based on torque compensation in anti-backlash geared servo system

This paper proposes the methods that convert two nonlinear characteristics into linear ones in anti-backlash geared servo system. The method to linearize the nonlinear stiffness of the anti-backlash geared train is suggested by investigating the frequency response characteristics. For the purpose of eliminating the nonlinear friction, a new non-model based torque compensator is applied to the servo system. The friction increased by the anti-backlash gear train is measured using torque equation in steady state. The design guideline of this compensator to guarantee the stability is established by describing function analysis and R-H method. In the end, the performance of designed controller is demonstrated by the results of simulation and experiment both in the frequency and in the time domain.