Dynamic modeling and robust vibration control of a high-speed macro-micro gripping system

Abstract

This paper presents dynamic modeling and robust vibration control for a high-speed macro–micro gripping system comprised of an air-floating macro-positioning stage and a compliant piezoelectric microgripper. A dynamic displacement coupling model is established considering rigid-flexible coupled macro-micromechanical structures, electromechanical properties containing the piezoelectric actuator and power amplifier, and hysteresis nonlinearity. Then, a comprehensive position/force model is proposed by integrating displacement, load, and force characteristics to describe the position and gripping force of micro-objects. Regarding system disturbances and model uncertainties, robust control strategies for pure displacement and position/force cooperation are devised utilizing perturbation H∞ controllers and Kalman filters. Experimental results indicate that measurement noises for pure displacement and position/force are effectively reduced. Position/force disturbances arising from sudden mutual changes are decreased from 14.39 μm and 7.25 mN to 0.82 μm and 0.85 mN. Also, position/force vibrations excited by high-speed macro motion are suppressed by 31.99 % and 58.06 %. Both precision tracking and vibration suppression are still well achieved, even at significant parameter perturbation. Thus, experiments verify the feasibility of the proposed control strategy.