STATE FEEDBACK H_ CONTROL OF MANIPULATORS WITH FLEXIBLE JOINTS AND LINKS

Abstract

A two-stage control strategy composed of rigid-body motion based partial feedback linearization and state feedback H_ control for robotic manipulators with flexible joints and links is presented. The partial feedback linearization control synthesized by the differential geometric Structure Algorithm is an input-output decoupling and linearization feedback law capable of precise rigid-body motion based trajectory tracking, but the zero dynamics of the unobservablc nonlinear elastic subsystem remains unstable. In order to actively suppress the elastic vibrations, it is necessary to sacrifice the perfect rigidbody motion based tracking capability somewhat by introducing a robust stabilization control in the vicinity of the desired trajectory. The elegant state space solution of M_ control has great application potential.The use of state feedback H- control with integral action for the synthesis of the robust stabilization control is shown effective to achieve active damping of elastic vibration and robust tracking of motor dynamics. A two-link arm is used in the numerical study.