Control of uncertain systems with guaranteed performance

Approximation-free controllers are proposed for the output tracking control of a class of multi-input multi-output uncertain systems. The proposed state feedback and output feedback controllers incorporate high-gain observers to estimate the system uncertainty. The tracking error of the closed-loop system is guaranteed to be semi-globally uniformly ultimately bounded. The proposed control architecture is simple without any approximation components for unknown system dynamics, and, therefore, any robustifying components for the compensation of approximation errors. Simulations performed on two benchmark problems illustrate the effectiveness of the proposed output feedback controller.