FPGA Based Adaptive Sliding Mode Control of a Piezoelectric-Driven Micropositioning System

The design and implementation of a novel adaptive terminal sliding mode controller (ATSMC) for precise position control of a piezo-driven positioning system is presented in this paper. The proposed ATSMC scheme needs the output feedback only and does not depend on observer, which reduces the heavy burden of controller algorithm implementation. Nonsingular terminal sliding surface is introduced to achieve fast and finite-time convergence for the trajectory tracking, and also to remove the singularity phenomenon in traditional terminal sliding mode method. An adaptive law is proposed to modify the the controller switching gain online, which provides stable and chattering free control quality. The stability of the developed control scheme has been theoretically proved. The proposed controller is implemented on a field programmable gate array (FPGA) platform for experimental investigation, and its performance and advantages are shown by comparison experimental study.