Abstract: Multi-DOF spherical initiative joint droved by spherical motor directly. It has high mechanical integration and advantage in the control and trajectory planning. But when the joint works, the friction and wear due to mechanical support, resulting in joint components fever, leading to joint static and dynamic performance deteriorated. Based on the motor technology, magnetic levitation technology and robot technology, presents a no mechanical friction and wear, no lubrication reluctance many degrees of freedom magnetic suspension ball joint initiative structure. Its working principle is that according to the air gap magnetic of active joint，derivate rotation angle displacement and radial displacement of the spherical rotor and calculated the total levitation force and electromagnetic torque model in a joint derivation coordinates. Based on the levitation force and torque model, it established active joint system dynamics model and inverse model. The inverse system model is as a decoupling controller, decoupling the prototype system and get pseudo-linear system. The systems controlled by the pseudo-linear state feedback closed-loop, and its simulation study. Simulation results show that the system has good dynamic response and robust anti-jamming features.

Key words: Decoupling control, Inverse system, Magnetic levitation, Mathematical model, Spherical driving joint, quartz crystal vibration robustness phase noise electromechanical coupling electromechanical integrated optimization