Controller Design for a Compliant Parallel Mechanism

This research presents control of a XY Nano-positioning stage using a compliant parallel mechanism with small crosstalk and yaw motion that are used in atomic force microscopes (AFM). The stage consists of two flexure displacement amplifiers driven by piezoelectric actuators. The piezoelectric actuator is explored to simultaneously reduce error of motion and fine motion tracking using controller. After identifying the system features, the Bouc–Wen hysteresis Model is established and the parameters of model are identified through particle swarm optimization (PSO) algorithm. An inverse feedforward control strategy is developed, then the PI controller is designed based on Ziegler-Nichols method. At the end, the performance of the mechanism is evaluated.