STABILITY-ROBUSTNESS ANALYSIS FOR LINEAR-SYSTEMS WITH STATE-SPACE MODELS

The stability-robustness analysis for linear systems with state-space models is considered. The fundamental problem of linear control system s subject to unstructured perturbations is addressed, and the results are extended to the consideration of linear control systems subject to linear structured perturbations. A modified time-domain Lyapunov-base d method of stability-robustness analysis is proposed where iterative interpolations of quadratic Lyapunov functions are considered. By use of the proposed method, less conservative allowable perturbation bound s are obtained, and the resulting Lyapunov matrices possess structural informations closely related to the perturbation-susceptible characte ristics of the nominal system state matrix. The robustness behaviour o f a vertical takeoff and landing (VTOL) aircraft control system, desig ned by use of the LQR state-feedback method, is illustrated.