Accurate Calculation of 3-D Model of a New Type of Double Stator Permanent Magnet Spherical Motor

A new type of double stator multi-DOF permanent magnet spherical motor (DS-PMSM) is proposed, which consists of two stators and a hollow rotor with PMs attached to its inner and outer surfaces. Through the joint action of the rotating motor and six arc-shaped permanent magnet linear motor arrays, it can realize the helical motion of continuously changing the direction of the rotating shaft, and can be applied to fields requiring multi-DOF motion such as industrial robots, aerospace, satellite communication. Considering that the spherical structure of the new motor has curvature in the circumferential direction and the axial direction, the curvature in the circumferential direction corresponds to the preliminary design of the 2-D cross-section, and the curvature in the axial direction corresponds to the accurate calculation of the 3-D model. Based on the preliminary design of 2-D cross-section of motor in the last article, an ideal 3-D structure is designed. Due to the limitation of existing machining technology, it can not meet the machining requirements of ideal spherical motor. Therefore, the structure is improved and the key parameters are optimized. Firstly, the improvement of the ideal spherical motor structure is described in detail. Considering the influence of helical motion on rotary motion, the optimal flattening coefficient of the inner PM is selected, and the inner PM are optimized in sections, so as to meet the electromagnetic performance and deflection angle and reduce the processing cost and difficulty. A torque measurement system platform based on six-axis force sensor is built to measure the influence of different rotation speed, deflection angle and stator current on the measured torque. The research results provide some reference value for the design of this kind of spherical motor.