A Novel Moving Coil Linear-Rotary Electromagnetic Actuator based on Unipolar Permanent Magnet

According to the complexity of using two or more single DOF motors and links for two-degree-of-freedom (2-DOF) drive application, this paper presents a novel 2-DOF linear and rotary machine (LRM) as an electromagnetic actuator that can move in rotary and linear direction. Two units of the machine share the same unipolar permanent magnet stator, which can not only reduce the amounts of permanent magnets to save costs, but also shorten the axial length of the motor effectively on the basis of reducing the electromagnetic coupling between two parts of the actuator. The Linear and rotating armature windings and the unipolar permanent magnet stator of the actuator are designed comprehensively to obtain a reasonable electromagnetic scheme. Characteristics of the actuator are analyzed by Finite Element Analysis (FEA). As a result, the actuator meets the design requirements that 1Nm of the torque in rotary motion and the average thrust is 23.8 N in linear motion.