Partial linearization by dynamic feedback for systems with perturbed input vector fields

Input-output linearization and decoupling by feedback are considered for minimum phase systems with perturbation terms in the input vector fields. Perturbations inducing a reduction in relative degree are considered. The perturbed system may then be partially linearized by feedback. It is shown that a dynamic feedback can be used to achieve linear and decoupled input-output relations for the perturbed system that are of the same order as those obtained by static feedback for the unperturbed system. The dynamic feedback law is advantageous because it reduces the excursions at the plant input while maintaining control accuracy. Examples are presented.