06 November : PhD defence of Tais Calliero Tognetti from Brasil, 11h30 visio-conférence, salle de Direction
Titre : Commande de systèmes dynamiques : stabilité absolue, saturation et bilinéarité
Jury : J. Daafouz (CRAN, Nancy, France)
J.M. Gomes da Silva Jr (UFRGS, Porto Alegre, Brasil)
V.F. Montagner (UFSM, Santa Maria, Brasil)
I. Queinnec (LAAS-CNRS, Toulouse, France)
S. Tarbouriech (LAAS-CNRS)
P.L.D. Peres (UNICAMP, Brasil)
Abstract : This thesis presents contributions to the solution of the problems of stability analysis and synthesis of state feedback controllers for dynamic systems with non-linear elements, by means of conditions based on linear matrix inequalities and Lyapunov functions. For switched systems subject to saturation in the actuators, convex conditions to design switched and robust controllers are presented. The saturation is modeled as a sector non-linearity and an estimate of the domain of stability is determined.
For linear systems with polytopic uncertainties and sector non-linearities, convex conditions of finite dimension to build Lur’e functions with homogeneous polynomially parameter dependence are provided. If satisfied, the conditions guarantee the stability of the entire domain of uncertainty for all sector non-linearities, allowing the design of linear and non-linear robust state feedback stabilizing controllers.
For continuous and discrete-time unstable bilinear systems, a procedure to design a state feedback stabilizing control gain is proposed. The method is based on the alternate solution of two convex optimization problems described by linear matrix inequalities, providing an estimate of the domain of stability. Extensions to handle robust and linear parameter varying controllers are also presented.
Key-words: Bilinear systems. Switching systems. Saturation of actuators. Lyapunov functions. Linear matrix inequalities. Sector non-linearities. Stability domain.