Composite nonlinear control with state and measurement feedback for general multivariable systems with input saturation

We present here a design procedure of composite nonlinear feedback control for general multivariable systems with actuator saturation. We consider both the state feedback case and the measurement feedback case without imposing any restrictive assumption on the given systems. The composite nonlinear feedback control consists of a linear feedback law and a nonlinear feedback law without any switching element. The linear feedback part is designed to yield a closed-loop system with a quick response, while at the same time not exceeding the actuator limits for the desired command input levels. The nonlinear feedback law is used to reduce the overshoot caused by the linear part as the system output approaches the target reference. The application of our technique to an air-to-air missile autopilot system shows that the proposed design method yields a very satisfactory performance.