Adaptive Extended State Observer-Based Synergetic Control for a Long-Stroke Compliant Microstage With Stress Stiffening

Abstract

In this article, the ultrahigh-precision planar motion control problem is investigated for a novel long-stroke multileaf spring based microstage, by considering the cross-axial coupling-induced varying stiffness. In particular, a discrete-time dynamical model with the stress stiffening effect is presented in a parameter varying form, where a discrete-time adaptive extended state observer (ESO) with exponential forgetting factor is developed based on Kalman-like observer method, and a synergetic control theory (SCT) approach is further proposed combining the observer structure to achieve microscale multiaxis motion control. The conditions on the convergence of the adaptive ESO and the robust stability of the closed-loop system are also derived with a theoretical analysis. Finally, the proposed control architecture is implemented (in real time) on a designed microstage, demonstrating significant performance improvement over existing results such as proportional-integral-derivative (PID) control and conventional active disturbance rejection controllers control methods.