Output feedback adaptive control of robot manipulators using observer backstepping

In this paper we present an observer-based adaptive control scheme for robot manipulators, for which we have both unmeasured velocity and uncertain parameters. Using the observer backstepping method, a reduced-order adaptive velocity observer can be designed independently from the state-feedback controller, which uses damping terms to compensate the presence of the estimation error in the tracking error dynamics. The resulting closed-loop system is semiglobally asymptotically stable with respect to the estimation error and tracking errors. Furthermore a simulated example shows the performance of the control scheme applied to a two-link manipulator.