System identification and vibration control of a piezo-driven flexure-based xyz parallel micropositioning stage

This paper presents experimental investigations on vibration control of a piezo-driven micropositioning stage aiming at a submicron-Accuracy motion tracking. The stage has decoupled XYZ translationalmotions and is featured with flexure hinges and parallel kinematics. The flexure structure renders the stage a lightly damped resonant mode, and the stack piezoelectric actuator (PZT) introduces hysteresis behavior into the system. The obtained frequency responses of the system confirm the decoupled property of the stage, which allows the adoption of single- input-single-output (SISO) control strategy for each of the three axes. A low-pass filter is employed to reduce the noise level and an integral resonant control (IRC) scheme is adopted to damp the resonant mode. An additional high-gain integral feedback control is implemented to alleviate the hysteresis effects and to achieve a suitable bandwidth with sufficient stability margin. The effectiveness of the combined controller is verified by extensive simulation and experimental studies. Results show that the ad- verse vibration, hysteresis and noise of the piezo-driven stage are well attenuated, which validates the effectiveness of the presented control scheme.