A Compound Method for Identifying and Suppressing the Thrust Fluctuation of Synchronous Linear Motor

Thrust fluctuation of linear motor is caused by many factors, of which the detent force caused by cogging effect and end effect changes periodically with the displacement of linear motor mover, and non-periodic thrust fluctuation is caused by the change of load resistance, nonlinear friction, motor parameters changing and other factors. If the detent force feedforward compensation or disturbance observer (DOB) is used simply to suppress thrust fluctuation, the effect is not satisfactory. In this paper, the two methods mentioned above are combined effectively. The parameters of the detent force model are identified by the improved tabu search algorithm, on the basis of this, a feedforward controller is designed, and the integral + proportional form DOB is applied to form a compound controller. The experimental results show that the proposed method fully suppresses thrust fluctuation of linear motor, and the system tracking accuracy is improved significantly.