On Region of Attraction Analysis of Nonlinear Flight Dynamic System

Current practice for flight stability analysis relies heavily on linear analysis and nonlinear, high-fidelity simulations. In the paper, the method of region of attraction analysis based on Sum Of Square (SOS) theory is proposed and applied on nonlinear system to estimate its stability. The polynomial model of aircraft is deduced from the nonlinear dynamic model, and then the stable flight region is calculated. Simulation results show that the aircraft can resume stable flight while its initial condition is in the region of attraction. The methodology provides a new way to research the stability and control of the nonlinear flight dynamic system. In addition, it has practical significance for guaranteeing the flight safety.