Linear System Control via Dynamic Saturating Actuators

Abstract

The problem of controlling systems via saturating actuators is addressed. In most previous studies the actuator is represented by a simple saturation. However, there are practical situations where such simple model is insufficient. Then, the actuator dynamics must be accounted for. Presently, a more convenient model is used that takes into account both the dynamics and the saturation of the actuator. A saturated output feedback controller is then developed for the whole ‘actuator-plant’ system, using a backstepping-like design technique. The closed-loop system is analyzed using the input-output stability theory. Sufficient conditions are thus established that guarantee the closed-loop stability and the fact that both the actuator and the controller stop saturating after a finite transient period, implying perfect tracking of the output reference signal provided this is compatible with the actuator constraint.