Robust ESO Based Control for Interval Plant: Application to Piezoelectric Positioning Stage Working at Changing Temperatures

There are a number of challenges in precision control of piezoelectric actuated micro/nano-motion devices, including uncertainty in modeling and environmental disturbances. Especially, the parameters of piezoelectric actuated systems may wander noticeably at varying temperatures due to the intrinsic properties of piezoelectric materials. In this work the issue is addressed by importing an interval model to cover all kinds of uncertainties and developing a robust extended state observer(ESO) based control which can limit the closed-loop zeros and poles to acceptable areas although the interval plant exists. With the aid of an equivalency between linear ESO-based control and a type of two-degree-of-freedom controller and root locus approach, all of the controller parameters are adjusted collaboratively in the proposed method. Lastly numerical simulations are performed to validate the effectiveness of the proposed method and to compare it with a conventional ESO based control.