Composite adaptive control of uncertain nonlinear systems using immersion and invariance method

The design of a novel composite adaptive control system for a class of uncertain systems using immersion and invariance (I&I) theory is presented. The interest here is to achieve a composite I&I adaptive control in the presence of model parametric uncertainties. Two sources of parameter information are combined for the parameter adaptation, which consists of tracking-error based adaptation law and prediction-error based adaptation law. Particularly, the tracking-error based adaptation law is constructed using I&I theory, which leads to a more flexible and effective design process of adaptation law. Stability analysis is presented using Lyapunov theory. Representative simulations are carried out on the mass-damper-spring system, which illustrate the superiority of the proposed composite I&I control scheme over the standard one.