Development of a spherical motor driven by electro-magnets

This paper presents a spherical motor driven by electro-magnets that can rotate omnidirectionally with some degrees of rotation angle error independent of rotation direction. The spherical motor is composed of a spherical rotor, a semi-spherical stator, a control PC, a control circuit, and a DC power supply. The rotor has 92 neodymium magnets. On the other hand, 84 electro-magnets are arranged on the stator. Each electro-magnet can be excited to north or south magnetic pole. The control PC calculates the posture of the rotor after a small time interval and generates the pattern of excitation of electro-magnets in order to rotate the rotor to its calculated posture. The results of the performance of the developed spherical motor show that the maximum torque is 0.24 (N·m), the maximum rotation speed is 2.5 (rad/s), and the average error of rotation angle is several degrees.