A two-stage controller for vibration suppression of flexible-link manipulators

A two-stage controller is utilized for vibration damping and end-effector trajectory tracking of a two-link flexible manipulator. The controller design strategy is based upon an inner-loop controller attained through asymptotic expansions and an outer-loop controller for further vibration damping and robustness enhancement of the closed-loop dynamics to parameter variations and unmodeled dynamics in the system. The outer-loop controller is a linear output feedback designed according to a frequency-weighted quadratic cost criterion. The control methodology advocated by the author is applicable to the multilink flexible manipulators. The asymptotic expansion analysis is extended to the force control of flexible-link manipulators. The experimental setup is described