Oscillation elimination of tip regulation for a single-link flexible manipulator

Many existing variable structure control schemes for flexible manipulators use a conventional sliding surface, which is linear with respect to system states. It results in a reduced-order sliding motion, i.e. the closed-loop dynamics during ideal sliding has reduced number off eigenvalues to be assi gned, and the fixed eigenvalue at the origin functions as integrator and ma y degrade system robustness. In this paper, an integral-type sliding surfac e is proposed which obtains a full-order sliding motion, such that all the eigenvalues of the closed-loop dynamics can be assigned. The integral-type sliding surface is derived from a reference model which does not have any f inite zero but all negative real poles. In order to force the system to fol low the reference model in the presence of the unstructured uncertainties, a variable structure controller is adopted. When in sliding mode, the syste m performs as the reference model. Hence there will be no vibration and the tip position regulation can be achieved when the system approaches steady- state. Simulation results demonstrate the effectiveness of the proposed app roach. Copyright (C) 2001 John Wiley & Sons, Ltd.