Adaptive control of systems with nonsmooth input and output nonlinearities

Adaptive control schemes are developed for plants with unknown nonsmooth nonlinearities at both the input and output of a linear dynamics. New controller parameterizations with nonlinearity inverses for parameterized nonlinearities are employed. When implemented with true parameters and properly initialized, the inverse controller ensures closed-loop signal boundedness and output tracking. Adaptive laws are designed to update the parameter estimates to implement adaptive inverse controllers for unknown nonlinearities in two cases: the linear part known and the linear part unknown.