NONLINEAR RE-ENTRY FLIGHT CONTROL SYSTEM ROBUSTNESS EVALUATION USING INTERVAL ANALYSIS

A stability robustness analysis is performed on a re-entry vehicle flight control system. The mathematical model of this system is nonlinear and may contain uncertain parameters, for which a set of models has to be examined instead of a singleton. The robustness evaluation is performed using interval analysis, which allows one to certify uncertainty regions affecting the closed-loop system. The celebrated Lyapunov function is taken as the stability criterion for the closed-loop system with uncertainties, since the existence of this function provides sufficient stability condition. The result shows the feasibility of the method for nonlinear system analysis.