A Friction Compensation Algorithm Based on Sliding Mode Control

Aiming at the problems caused by nonlinear friction on precision optical servo platform at low speed, a novel sliding mode control (SMC) algorithm with adaptive gains is studied. Integral term is introduced to design sliding surface, and the Twisting control (TC) algorithm based on the idea of higher-order SMC is selected as the switching control law. Nonlinear gradient gains are proposed originally to solve the chattering problem of conventional TC. Then, Anti-windup method is particularly taken into consideration. Simulation results show that the proposed SMC algorithm can effectively compensate the adverse effect of friction on the system control performance at low speed, and in compare with PI algorithm and conventional TC, it achieves faster response, higher accuracy and stronger robustness.