ADAPTIVE TRACKING CONTROL DESIGN OF CONSTRAINED ROBOT SYSTEMS

Both dynamic state feedback as well as output feedback tracking contro l designs are presented in this paper for constrained robot systems un der parametric uncertainties and external disturbances. The previous s tudies on tracking control design, not considering the velocity measur ements, address only the unconstrained robot design. In contrast, a dy namic output feedback controller based on a linear and reduced-order o bserver that uses only position measurements is proposed here for the first time to treat the trajectory tracking control problem of constra ined robot systems. Both adaptive state feedback control schemes and a daptive output feedback control schemes with a guaranteed H-infinity p erformance are constructed. It is shown that all the variables of the closed-loop system are bounded and a pre-assigned H-infinity tracking performance is achieved, in the sense that the influence of external d isturbance on the tracking motion error can be attenuated to any speci fied level. Moreover, it is also shown that the motion and force traje ctories asymptotically converge to the desired ones as the dynamic mod el of robot systems is well-known and the external disturbance is negl ected. Finally, simulation examples are presented to illustrate the tr acking performance of a two-link robotic manipulator with a circular p ath constraint by the proposed control algorithms. (C) 1998 John Wiley & Sons, Ltd.