Linear Oscillatory Actuator with Magnetic Bearing

This paper describes the control of a magnetic bearing system used in a linear oscillatory actuator. The actuator consists of a stator inductor, a piston and two magnetic bearings. The piston is levitated by the two magnetic bearings in the lateral direction and driven by the magnetic force between the three magnetic coils of the stator inductor and the two permanent magnets of the piston in the axial direction. Forward and reverse motions of the piston are available by alternating the direction the exciting current in the coils. The dynamic characteristics of the linear oscillatory actuator are analyzed theoretically and the magnetic bearings are controlled by PID and H8 control methods.