Restricted trajectory tracking in nonlinear systems

The exact linearization of nonlinear control systems provides a useful meth od for designing feedback controllers based on the linear model in which th e nonlinear plant is transformed. This paper deals with three drawbacks inv olved in this method when used for engineering applications, specially for solving the trajectory tracking problem: 1) the feedback control must be bo unded, with previously set bounds, 2) the evolution of the state variables must lie within a determined region of the state space, and 3) all the syst em states are needed in order to design the closed - loop tracking control. Conditions for satisfying the above mentioned requirements are given. A fee dback control that solves the trajectory tracking problem with the imposed constraints is designed. The state estimates are given by a nonlinear reduc ed - order observer. An application to a robot manipulator is shown.