Stability radii based robust wedge-stability analysis and synthesis of continuous constrained systems

In this paper, based on stability radii, a sufficient condition is first proposed to ensure robust wedge-stability of continuous-time constrained systems with state feedback. The saturated actuator is reformulated as a conditioned linear actuator subject to structured uncertainties and an auxiliary matrix is introduced to make the closed-loop system be characterized into a scheme of stability radius approach. We also investigate the issue of maximizing complex stability radius corresponding to a wedge region by state feedback, where a desired maximizing state feedback controller can be obtained via iteratively solving a parametrized Riccati equation. An example is given to illustrate the feasibility of the proposed results.