High precise position control of a novel electromagnetic actuator using sensorless detection

High precise position actuators are widely applied in the fields of civilian and military industry, aviation and aerospace etc. A novel linear electromagnetic actuator system for position servo applications is described in this paper. The actuator is made of an N_dF _eB permanent magnetic moving part, which can return to equilibrium point and have hold force during the excitation power off, a stator with double excitation coils and two operating gaps. By changing the combination of the two electromagnetic excitations, the actuator can run in four quadrants of acceleration or braking in duel direction. Changing the coil current can regulate the acceleration/deceleration and the hold force. Using sensorless position detection to form feedback loop, the control system can realize high precise position and speed servo control following the motion command input. Its controller is based on a single chip processor (SCP) with high accurate A/D converter to realize position information conversion, and the controlling software can program the control strategy, calculate the position feedback parameters, make non-linear compensation and keep dynamic stabilization. This paper deduces the transfer function, calculates the magnetic field distribution of the actuator using finite element analysis and provides effective methods to realize high precise position servo control