Stabilization for a class of non-affine systems via reduced-order dynamic output feedback

Sufficient conditions of global stabilization for a class of multi-input and multi-output continuous-time and/or discrete-time nonlinear systems are presented. The systems discussed in this work are not necessarily affine in input, but they may possess Lyapunov stable control-free dynamics. The stabilizing controllers introduced in the paper are dynamic output feedbacks based on reduced-order state observer. The asymptotic stability of the closed loop system is checked using LaSalle´s invariance principle. By means of Lyapunov approach a separation principle is established for the design of feedback control law and observer in the stabilizing dynamic output controller, respectively.