Enhanced sliding-mode constrained motion tracking control of piezo-actuated flexure-based mechanisms

This paper presents an enhanced sliding-mode constrained motion tracking control methodology for piezo-actuated flexure-based micro/nano manipulation mechanisms. This control methodology is formulated to accommodate not only the parametric uncertainties and unknown force conversion function, but also the non-linearities including the hysteresis effect and external disturbances in the manipulation mechanisms. The control objective is to track desired motion trajectories in a constrained environment. In this paper, the equations for the dynamic modelling of a flexure-hinged four-bar micro/nano manipulation mechanism operating in a constrained environment are established for the formulation of the control methodology. Stability of the proposed closed-loop system is analysed, and the convergence of the motion tracking errors is proven theoretically. Furthermore, precise motion tracking ability in following a desired motion trajectory is demonstrated in the experimental study.