Anti-disturbance control of a piezo-driven micromanipulator with a non-minimum phase

In precision micromanipulation tasks, operation accuracy and anti-disturbance performance of micromanipulators are critical. This paper presents anti-disturbance control for a piezo-driven micromanipulator with a non-minimum phase. The micromanipulator is constructed by mounting a flexible manipulator on a parallel positioning stage. The micromotion and dynamic behavior of the micromanipulator are analyzed. Then, an anti-disturbance control strategy combining H-infinity feedback control and disturbance observer-based control for a non-minimum phase is designed to reduce disturbances and ensure control accuracy. Finally, the experimental measurement and control system is built. The observed phenomena show that sinusoidal disturbances are almost eliminated and the overshoot of step disturbances is significantly reduced. In addition, the time for suppressing the step disturbance is shortened from 0.9 to 0.3 s. Experiments verify the viability of the anti-disturbance control strategy.