Theory and experimental results on output regulation for nonlinear systems

Output regulation is the problem of finding a control law by which the output of the system we are interested in can asymptotically track another output generated by an exosystem and, simultaneously, reject undesired disturbances. The control law must also asymptotically stabilize the system whenever the exosignal is absent. Without loss of generality, both the exo-output and the disturbances can be viewed as an output of an augmented exosystem. In the literature, the word augmented is usually dropped. In this paper, the theories of output regulation are presented and successfully implemented on an under-actuated system: the Pendubot. The objective of the experiment on the Pendubot is to perform tracking and maintain the second link in the upright position. Experimental comparisons between different methods are discussed.