Global tracking and disturbance rejection of a class of lower triangular systems subject to an unknown exosystem

In this paper, we study the asymptotic tracking and disturbance rejection problem for a class of uncertain nonlinear lower triangular systems subject to an uncertain exosystem. The same problem was studied before for the same class of systems with the objective of asymptotic tracking only. By utilizing a newly developed robust adaptive controller design approach, we are able to simultaneously handle the objectives of disturbance rejection and asymptotic tracking.