A Novel 4-DOF Hybrid Magnetic Bearing for DGMSCMG

In this paper, a novel structure of four degrees of freedom (4-DOF) hybrid magnetic bearing is proposed for double gimbal magnetically suspended control momentum gyro (DGMSCMG). It includes two active parts and one passive part, and every active part has eight stator magnetic poles around the circumference in X and Y directions, which are divided into upper and lower layers. The passive part has two whole magnetic rings, which is located in the middle of this 4-DOF hybrid magnetic bearing. The radial active force is analyzed by equivalent magnetic circuit method (EMCM) and the axial resilience force is analyzed by the infinitesimal method based on the end magnetic flux. Meanwhile, three-dimensional finite-element model of the 4-DOF hybrid magnetic bearing is established with ANSYS software, and the radial displacement versus radial force, the current versus radial force, and the axial displacement versus axial resilience force characteristics are analyzed compared with the EMCM. Furthermore, the 10 Nms DGMSCMG prototype with the proposed 4-DOF hybrid magnetic bearing is manufactured, and the experiments of the radial active force test and the axial resilience force test are carried out. Experimental results show that the presented 4-DOF hybrid magnetic bearing has good force performance and verify the correctness of the theoretical analysis.