Adaptive fuzzy exponential sliding-mode control system design for voice coil motors

In this paper, an adaptive fuzzy exponential sliding-mode control (AFESMC) system, which is composed of a computation controller and an exponential compensator, is proposed for a voice coil motor (VCM). Within the computation controller, a fuzzy observer with an online structure and parameter learning ability is used to online approximate an unknown nonlinear term of the system dynamics. The exponential compensator not only can eliminate the effect of the approximation error introduced. Finally, a 32-bit ARM Cortex-m4 microcontroller is used to implement the control scheme. The experimental results show that the AFESMC system can achieve favorable tracking performance and is robust against payload variations and change in reference speed of VCM applications.