Performance enhancement of fixed regulating systems via actuator saturation

Developed in this paper is a controller design technique that utilizes actuator saturation to meet stringent output performance specifications for regulating systems with fixed components. Regulating performance is achieved via the design of a linear controller that saturates the actuator for large step disturbances yet operates linearly for smaller step disturbances. The controller is designed using a pseudo-linearization technique based on a describing function approach. Such an approach retains the advantages of a frequency domain technique including the enforcement of time domain performance specifications and the incorporation of model uncertainty. The resulting control law provides an improved regulating performance for large step disturbances without requiring a larger actuator. For small step disturbances, the control system maintains linear operation and provides desirable system response characteristics.