An observer-based IT2 TSK FLS compensation controller for PMSM servo systems: design and evaluation

It is hard to achieve precise displacement for the permanent-magnet synchronous motor (PMSM) servo systems due to the nonlinear friction and time-varying end-load. This paper proposes an observer-based compensation control strategy to cope with the above issues. First, an adaptive interval type-2 Takagi-Sugeno-Kang (TSK) fuzzy logic system is adopted to estimate the inherent friction. By utilizing the tracking and modeling error, the composite adaptive updating law is constructed to improve the tracking performance. Then, the residual reconstruction errors and the bounded end-load are estimated and compensated by the designed disturbance observer. Estimation of friction and disturbance observer, as compensation terms, are employed in traditional cascade control. Finally, the proposed controller guarantees the tracking error is uniformly ultimately bounded based on Lyapunov theory. Simulations and experiments are presented to verify the effectiveness and superiority of the proposed controller.