Adaptive fuzzy tracking control based on backstepping for permanent magnet spherical motor

This paper presents an intelligent tracking control method for a three degrees-of-freedom permanent magnet spherical motor (PMSM). The control method is designed on the basis of the establishment of dynamics model for spherical motor according to Cardan angles. By the use of backstepping design, the nonlinear system of PSMS is divided to several subsystems with less order than that of original system. Moreover, due to an adaptive fuzzy controller, the unknown dynamics of PSMS including external disturbance can be infinitely approximated. The stability of the close-loop system using designed controller is confirmed through Lyapunov theorem. Simulation results are provided to validate the effectiveness of the proposed method.