Global Output Feedback Stabilization of Nonlinear Systems With Nonlinearity of Unmeasured States

This technical note deals with global stabilization of class of nonlinear dynamic systems using output feedback. The systems considered have nonlinear functions of unmeasured state variables, in addition to nonlinear functions of the system outputs. A nonlinear reduced order observer is proposed to estimate the unknown system states. Estimated state variables are used for control design, together with the system output. Certain conditions are identified for the proposed observer and control design. Under these conditions, the proposed control design ensures the global asymptotic stability of the closed-loop control system.