Micro-/Nanopositioning Using Model Predictive Output Integral Discrete Sliding Mode Control

A piezo-driven micro-/nanopositioning system requires an appropriate controller to suppress the inherent nonlinearity and disturbances. In this paper, we propose a new control scheme called model predictive output integral discrete-time sliding mode control (MPOISMC) to achieve a precise positioning using a piezostage. The proposed controller is featured by an integral type of sliding function based on output error along with a sliding mode state observer. The major advantage of the scheme lies in that it is very easy to implement since it only requires a low-order linear model, whereas neither the bounds on system uncertainties nor the hysteresis model is needed. The model predictive control methodology and the integral item are used to eliminate chattering phenomenon, and a low tracking error is achieved. The feasibility and effectiveness of the proposed MPOISMC approach are verified by experimental studies performed on a micro-/nanopositioning piezostage. Results show that a real-time precise positioning is realized and the performance of the controller is superior to the conventional PID control for motion tracking tasks. Owing to a simple structure, the control strategy can be easily extended to other types of micro-/nanopositioning systems as well.