This paper is concerned with the problem of stability regions determination for linear systems with saturating inputs. The paper focuses on a critical analysis of two known approaches to model the effect of actuator saturation: hybrid modeling and polytopic modeling. In each case, algorithms to determine ellipsoidal domains of stability for such class of systems are provided in terms of LMIs. The ability of such algorithms in providing large stability domains is analyzed by highlighting the main reasons they incorporate conservativeness, including the influence of the saturation modeling. Two examples are worked out illustrating how significantly the stability domains obtained by such algorithms can differ.
Control saturation; hybrid modeling; polytopic modeling; stability analysis
