Robust H-infinity minimum entropy static output-feedback control of singularly perturbed systems

The problem of designing static output-feedback epsilon-independent control lers for linear time-invariant singularly perturbed systems is considered. The controller is required to satisfy a prescribed H-infinity-norm bound an d to minimize the closed-loop entropy (at s = infinity) for all small enoug h epsilon. The optimal controller gain is designed on the basis of generali zed Riccati and Lyapunov equations with symmetric block (2,2), that are cou pled via a projection. This gain is either purely fast, purely slow or a co mposite one, depending on the structure of the output coupling matrix. A we ll-posed problem with a finite value of entropy for epsilon --> 0 is obtain ed by assuming that the entropy of the fast subproblem is zero or by scalin g the matrices of the system. In the first case the optimal controller is t he one that minimizes the entropy of the corresponding descriptor system. ( C) 2000 Elsevier Science Ltd. All rights reserved.