Torque modeling and analysis of spherical cctuators with iron stator

This paper presents a ball-joint-like three-degree-of-freedom (3-DOF) permanent magnet (PM) spherical actuator which features a ball-shaped rotor with multiple PM poles and a spherical iron stator with air-core coils. Torque output of this PM spherical actuator is formulated analytically. Based on the torque model, simulation result of the actuator torque variation is presented. In addition, the effect of the stator iron on the torque output is evaluated.