Disturbance observer-based nonlinear friction compensation in table drive system

This paper presents a disturbance observer-based algorithm for nonlinear friction compensation in table drive systems to achieve the high accurate trajectory control. In order to design an effective compenstator, dynamic characteristics of the friction are examined and, as a result, a simple but high accurate observer can be designed on the basis of the analyzed function characteristic. Using the disturbance observer based compensation, the precise velocity/position control can be attained without the response delay which is caused by the restricted control bandwidth in conventional compensation algorithms. Experimental results show the significant performance improvement of the proposed algorithm in the trajectory control with low feed rate and velocity reversal motion.