Flexure-hinges guided nano-stage for precision manipulations: Design, modeling and control

In this paper, a novel piezoelectric actuator driven nano-stage with bridge type mechanism is studied from the perspectives of design optimization, dynamical modeling, as well as controller synthesis for high precision manipulation purposes. FEM (Finite Element Method) analysis and dynamical modeling are provided to derive the system model including the hysteresis nonlinearity. Considering the complexities of dynamical uncertainties and hysteresis nonlinearity, an active disturbance rejection controller is developed consisting of extended state observer (ESO), state feedback controller and profile generator. With the proposed algorithm, the nonlinear dynamics, system uncertainties and external disturbances can be treated as part of the “total disturbances”, such that the extended state observer can be used to estimate and suppress the effects of these complex dynamics. The proposed control algorithm is deployed in real time implementations on the designed nano-stage, where experimental results demonstrate good control performance in terms of high precision positioning, hysteresis compensation and disturbance rejection.