Analysis and control of nonlinear loss of stability for longitudinal flight dynamics of hypersonic vehicle with high angle of attack

Bifurcation and continuation method is employed to address the issue of longitudinal loss of stability of high angle of attack of hypersonic glide vehicle. Based on the obtained codimension 1 equilibrium bifurcation branches presented in phase-parameter space, the stability of the branches and catastrophe are analyzed. The codimension 2 equilibrium bifurcation branches are then presented in phase-parameter space. The 3D surface of equilibrium for the full Mach number and angle of attack parameter space are given, including stable and unstable branch surfaces. The nonlinear dynamic inversion is utilized to design the controller for longitudinal dynamics. The overall open-loop and closed-loop eigenvalue are plotted. A new evaluation strategy for nonlinear closed-loop dynamics is proposed to evaluate the overall performance of the designed controller. Time-history simulation is combined to verify the efficacy and high performance of the controller.