The motion control algorithm and orientation detection methodology of a spherical stepper motor

The structure and operation principle of a PM spherical stepper motor and its gimbal guideway orientation detection system are discussed. According to the arrangement and combination of the permanent magnets and windings, a weighted graph is given which consists of all possible stable positions of the spherical stepper motor. Using the algorithm of the weighted graph, the commuting strategy can be attained and the expected trajectory can be achieved. On the basis of kinematic analysis of the rotor and gimbal guideway, the rigid body kinematic models of single rotor and rotor with the gimbal guideway are derived. Combined with the control strategy, simulations of actual stepping motions and the outputs of orientation detection system in the case of knowing targets points are carried out. Simulation results provide the references for the motion control strategy research and the experimentation design.