Nonlinear control design for linear time varying systems

A new class of linear controllers for linear time varying systems are proposed. These controllers are based on nonlinear tools such as integrator backstepping and nonlinear damping, and on a new filter structure that incorporates the time varying parameters. It is shown that these controllers can guarantee exponential convergence of the tracking error to zero when the plant parameters are known exactly. When the parameters are not precisely known but the time variations of the parameters associated with the system zeros are known, the appropriate choice of certain design parameters lead to a closed loop system with uniformly bounded signals and zero regulation error