Study Of Permanent Magnetic Spherical Motor

Many kinds of motors, such as AC, DC servo motors, steppers, which are currently used in robotic, wrist, laser cutter etc., can't effectively meet the needs of such complicated systems because of their high speed, small torque and one-DOF and therefore the spherical motor, which can provide many DOF, has been attached much importance since 50'.This paper discussed two-pole permanent magnetic spherical motor, in which two poles of rotor are permanent magnets. The electro-magnetic relationship is analyzed and the electro-magnetic model has been developed, which includes voltage equations, flux linkage equations, and electro-magnetic torque expressions. The model shows that the electro-magnetic coupling relationship inside the two-pole PM spherical motor is simple and that the torque of the motor is easy to control.Permanent magnetic spherical stepper (PMSS) is a novel kind of spherical motor, which has advantages of simple structure, small volume, light weight and high torque etc. The model of magnetic field inside PMSS is developed using integral equation method (IEM) and discrete expressions on field distribution are also derived. The results of IEM and FEM show the effectiveness and advantages of IEM for PMSS. On the basis of field analysis of PMSS, the paper describes the calculation of torque of PMSS using Maxwell Stress Method (MSM). The torque-angle characteristic of PMSS is also analyzed by MSM.