A control system for electrical/mechanical hybrid four-redundancy brushless DC torque motor

A control system of electrical/mechanical hybrid four-redundancy brushless DC torque motor applied to the direct drive actuator (DDA) is designed. To improve the response to the low-angle and the stability of DDA for aerial uses, the double closed loop structure of the position and current is associated with the current limit block adjusted by the speed, and the position loop adopts the variable structure PID to suit the small input. This current limit block enhances effectively the stability of the control system, and the variable structure PID in the position loop increases the accuracy of the response to the low-angle. Meanwhile the proposed control strategy has good frequency response characteristics and realizes the redundancies switching smoothly in running. The experimental results of the test platform for DDA verify the control effect of this system.