Adaptive Control of a Class of MIMO Nonlinear Systems in the Presence of Additive Input and Output Disturbances ⋆

In this paper, two controllers are developed for a class of MIMO nonlinear systems. First, a robust adaptive controlleris proposed and proven to yield semi-global asymptotic tracking in the presence of additive disturbances and parametricuncertainty. In addition to guaranteeing an asymptotic output tracking result, it is also proven that the parameter estimatevector is driven to a constant vector. In the second part of the paper, a learning controller is designed and proven to yielda semi-global asymptotic tracking result in the presence of additive disturbances when the desired trajectory is periodic. Acontinuous nonlinear integral feedback component is utilized in the design of both controllers and Lyapunov-based techniquesare used to guarantee that the tracking error is asymptotically driven to zero. Numerical simulation results are presented forboth controllers.