Introduction

Linear Plants with Actuator Saturation

The presence of actuator saturation in control systems, though frequently ignored, is due to inherent (and unavoidable) physical limitations of devices. The relevance of this issue from the practical viewpoint is more and more attracting the attention of control system researchers, as failure in accounting for actuator saturation may lead to severe deterioration of closed loop system performance, even to instability.

As a matter of fact, classical control theory suffers from the limitation that, in reality, dynamical systems are frequently affected by a number of ignored factors which may invalidate, or at least severely limit its effective application. Among these factors, inherent saturation effects turn out to be almost ubiquitous, since the output of all physical devices are limited to some degree, and when a limiting value is reached saturation is said to occur. A classical example is the output torque of a servomotor, which is subject to a maximum value which can be supplied.