Optimal output disturbances rejection control for nonlinear systems based on stability degree constraint

This paper considers the problem of optimal output disturbances rejection control for nonlinear systems based on stability degree constraint. The corresponding optimal output feedback control laws are derived from a Riccati equation and Sylvester matrix equations in finite-time and infinite horizon. We give the existence and uniqueness conditions of the optimal output control law. Then an observer which can solve the problem of the actual control state variables difficult to measure by using the signal of input variables u(t) and output variables y(t). With feed forward compensation, the impact of external disturbances is eliminated and achieved optimal output feedback control based on stability degree constraint. Finally, the simulation results show that the method is effective to reject external persistent disturbances, and the robustness is superior to the classical state feedback optimal control, and satisfy the stability degree constraint.