ADAPTIVE OUTPUT REGULATION OF A FLEXIBLE ARM

A self-tuned version of a constoller for asymptotic trajectory trackin g of the end point of a two-link flexible robot arm is presented. The bounded solution to the inverse system, which is used in the control l aw, is tuned by the estimates of the unknown robot parameters, generat ed by a least square identification scheme. Boundness of the state of the adaptive controller is achieved by a stabilizing linear feedback f rom the output error, with fixed gains and robust with respect to vari ations of the parameters. This guarantees the total stability of the s ystem, which is the main ingredient used in the proof of the controlle r properties, through a Lyapunov-like approach. The controller perform ance is finally illustrated by numerically simulating the tracking of an end point ramp under payload mass variations.