Enhanced sliding mode motion tracking control of piezoelectric actuators

This paper proposes an enhanced sliding mode motion tracking control methodology for piezoelectric actuators to track desired motion trajectories. The proposed control methodology is established to accommodate parametric uncertainties, nonlinearities including the hysteresis effect, and other un-modelled disturbances, without any form of feed-forward compensation. The fundamental concept in this control strategy relies on the specification of a target performance and the formulation of an enhanced sliding mode control law based on the variable structure control approach. The control methodology ensures the convergence of the position tracking error to zero in the presence of the aforementioned conditions. The stability of the control methodology is proven theoretically and a precise tracking ability is demonstrated in the experimental study. One of the most important advantages of this control methodology is that the approach requires only a knowledge of the estimated system parameters together with their corresponding bounds and the bound of the non-linearities and disturbances in the physical realisation. Being capable of motion tracking, the proposed enhanced sliding mode control methodology is very attractive in the field of micro/nano manipulation through which high-precision piezoelectric actuation control applications can be realised.