IEEE Transactions on Automatic Control, Vol.51, No.7, 1166-1171, 2006
A constructive approach to local stabilization of nonlinear systems by dynamic output feedback
The note considers the problem of local stabilization of nonlinear systems by dynamic output feedback. A new concept, namely, local uniform observability of feedback control law, is introduced. The main result is that if a nonlinear system is Nth-order approximately stabilizable by a locally uniformly observable state feedback, then it is stabilizable by dynamic output feedback. Based on the approximate stability, a constructive method for designing dynamic compensators is presented. The design of the dynamic compensators is beyond the separation principle and can handle systems whose linearization might be uncontrollable and/or unobservable. An example of nonminimum phase nonlinear systems is presented to illustrate the utility of the results.
Keywords:dynamic output feedback;local uniform observability;nonlinear systems;nonminimum phase systems;stabilization