Indirect adaptive fuzzy controller design for vertical direct-driven servo system

In order to deal with the uncertainties and nonlinearities within a permanent magnet line synchronous motor (PMLSM) vertical servo system, such as friction, thrust ripple and external disturbance, an indirect adaptive fuzzy (IAF) controller designed. The IAF controller comprises a supervisory controller and an equivalent controller. The supervisory controller is proved to guarantee the tracking error asymptotically stable without any requirement on the optimal approximation error (OAE). Simulation illustrate that the IAF controller can make the servo system track the reference signal accurately and has good robustness.