IEEE Transactions on Automatic Control, Vol.46, No.5, 742-746, 2001
A separation principle for the control of a class of nonlinear systems
In this note, we extend the separation results of a previous work to a case where a globally bounded state feedback controller renders a certain compact set positively invariant and asymptotically attractive. The extension covers a wide range of control tasks that arise in adaptive control, servomechanisms, and practical stabilization. It is shown that by implementing the control law using a high-gain observer, we can recover the performance of the state feedback controller.
Keywords:nonlinear control;observers;output feedback control;separation principle;singular perturbation