Positioning of piezo-driven XY table systems using fuzzy mixed H2/H∞ optimization-based decentralized model reference control

In this paper, the positioning of a piezo-driven xy table system via a fuzzy mixed H-2/H-infinity optimization-based decentralized model reference control is developed. Each subsystem contained 6 linear pulse transfer function systems (LPTFSs). The reference model for every LPTFS was first designed to shape the response of the closed-loop of the ith subsystem. Then the. H 2 - norm of the output error and weighted control input of the jth LPTFS was minimized to obtain a control. The H-infinity - norm of weighted sensitivity between output disturbance and output error of the jth LPTFS was minimized to attenuate its effect. In addition, a nonlinear control based on output error for every LPTFS was also established to improve robust performance. The experiments of piezo-driven xy table system confirmed the usefulness of the proposed control.