Wide range uncertain parameters are frequently encountered in numerous industrial systems due to changes in operating conditions. Meanwhile, in the practical engineering control system, input saturation constraint on the actuator frequently occurs due to the limitation of physical characteristics and the requirement of safe operation. The system performance is significantly affected by parametric perturbation and input saturation, making the control design complicated and difficult. The existence of these situations may lead to system performance degradation and even make the closed-loop system unstable. Hence, robust analysis and design of uncertain parametric systems with input saturation is a highly important issue in control engineering.

For achieving high performance of the practical control system, the improved robust control method is studied. How to deal with the parametric uncertainties and utilize the characteristic of the actuator saturation in system design is the key point. A practical system, a single-machine infinite-bus (SMIB) power system, is used as a typical case study to show the effectiveness and advantage.