Precision Motion Control of Permanent Magnet Linear Synchronous Motors Using Adaptive Fuzzy Fractional-Order Sliding-Mode Control

The aim of this study is to develop an adaptive fuzzy fractional-order sliding-mode control (AFFSMC) strategy to control the mover position of a permanent magnet linear synchronous motor (PMLSM) system. First, the mathematical model of the PMLSM is investigated by using the principle of field oriented control. Subsequently, a fractional-order sliding-mode control (FSMC) is designed by means of a new fractional-integral sliding surface. Because it is difficult to determine the hitting control gain for the FSMC in practice, the AFFSMC is further developed in which an uncertainty observer is developed to observe uncertainties while an adaptive fuzzy reaching regulator is designed to concurrently compensate for observation deviations and suppress the chattering phenomenon. The adaptive laws are derived to tune the control parameters online based on the Lyapunov stability theorem. Thus, the uncertainty bound information is not required while the chattering can be attenuated. Finally, experiments demonstrate that the proposed AFFSMC system performs the robust control performance and precise tracking response for the PMLSM drive system against the parameter variations and external disturbances.