Extending Linear Designs to Nonlinear Systems via Adaptive Architectures

This paper addresses observer/controller design problems for nonlinear systems from the perspective of augmenting linear designs. In both problems, an adaptive element is added to the nominal design to provide a correction that accounts for modeling errors. The error signal for adaptive laws is generated through a linear observer of the nominal system's error dynamics. Ultimate boundedness can be shown through Lyapunov's direct method.