The Estimation Error of Extended State Observer in Rigid-Flexible Coupling Motion Stage

Abstract

The rigid-flexible coupling motion stage (RFCMS) uses the elastic deformation of the flexure hinges to compensate the position error caused by the friction dead zone, and the disturbance to the working stage is converted from friction to elastic disturbance. After the observer estimates and compensates the elastic disturbance, the working stage can be equivalent to a frictionless system. However, due to the friction to the rigid frame in RFCMS and the machining error of the flexure hinges, as well as the measurement deviation, there will be errors in the measurement and the estimation of the observer, which affect the final position accuracy of RFCMS. This paper theoretically analyzes the influencing factors of the estimation error in extended state observer (ESO), and quantitatively studies the estimation performance of ESO, in order to provide a theoretical basis for the control scheme of RFCMS.