Robust controller based on friction compensation and disturbance observer for a motion platform driven by a linear motor

Non-linear friction and external disturbances affect the positioning accuracy of high-speed motion systems, especially of those impelled by linear motors. This paper presents a controller, which includes three parts: a proportional-plus-derivative (PD) feedback controller, a friction compensator, and a disturbance observer. The friction compensator is based on the LuGre model and compensates for non-linear friction. The disturbance observer is used to eliminate the friction compensation error and other external disturbances. Experimental results show that the controller gives high positioning accuracy and robust performance in the presence of disturbances for high acceleration motion over 5G.