Fuzzy adaptive multi-mode sliding mode control for precision linear stage based on floating stator

This paper outlines a precision motion stage actuated by using a voice coil motor with a floating stator. For getting good performance, a multi-mode sliding mode control (MMSMC) was designed to operate this linear motion stage. MMSMC contains two sliding mode controllers: a sliding-mode control (SMC) and an integral sliding-mode control. The switching of two SMCs will be activated according to the setting error threshold. In order to eliminate the chattering phenomenon, a soft switching control is developed to replace the signum function with a smooth function. To obtain improved performance, a fuzzy controller and an adaptive controller are introduced into the MMSMC to form a fuzzy adaptive multi-mode sliding mode control (FAMMSMC). The fuzzy control is adopted to tune the slope of the sliding mode function, and the gain of the switching control is tuned according to the adaptive law. The results of the experiments are provided to make a comparison with the FAMMSMC, MMSMC, and proportional-integral-derivative control. The experimental results show that good positioning and tracking performance can be provided by using FAMMSMC.