Adaptive Control of Noncanonical Nonlinear Systems With Time-Varying Dynamics

In this article, adaptive control designs are systematically studied for uncertain noncanonical nonlinear systems with time-varying dynamics. As a key system characterization, the relative degrees are directly defined for noncanonical nonlinear time-varying systems, and at the same time, the necessary time-varying parameter conditions are specifically derived for different system dynamics. Then, robust adaptive feedback linearization-based control designs are studied for noncanonical nonlinear systems with time-varying dynamics under different relative degree conditions. The designs ensure that all closed-loop system signals are bounded and the output tracking error is small in the mean. Simulation studies are presented for a time-varying noncanonical nonlinear aircraft model to show the effectiveness of the developed adaptive control schemes.