Disturbance suppression control with review action of linear DC brushless motor

This paper proposes a new preview and disturbance suppression control for a coreless type linear DC brushless motor (LDM). The brushless and coreless type linear DC motor is coggingless and has long life. It is suitable for high-speed operation and many precise positioning control purposes. However, it has disadvantages in that it is greatly affected by the parameter and load variation in the servo system with the LDM because it is not equipped with auxiliary mechanisms. The influence of the parameter variation and load change of the servo system are regarded as an equivalent disturbance signal and the compensation action is applied by utilizing the estimated value of the equivalent disturbance. The proposed control system is an optimal preview control system of type 1 comprising the estimation and compensating loop. In the proposed system, the disturbance suppression, improvement of phase delay of the whole control system, and lowering effect of the value of the input variables are attained in this control system for LDMs. Experimental studies for the LDM itself and a linear X-Y table made by the LDMs are shown and the above improvements are confirmed