Design procedures have been developed for adaptive control of nonlinear systems with both parametric and dynamic uncertainties and unmeasurable input disturbances, and their application to vibration damping of flexible structures is experimentally verified using this two-link flexible manipulator testbed at CRRL. The testbed consists of brush DC motors, joint encoders, an IBM data acquisition unit, a 486-based personal computer and a TMS320C30 DSP board. Some of the experiments conducted include positioning of unknown flexible payloads for robotic arms using a wrist-mounted force/torque sensor.