高超声速飞行器纵向大攻角非线性失稳分析与控制

针对滑翔式高超声速飞行器大攻角纵向失稳问题，基于连续算法和分岔理论，求解并分析了多特征点单参数分岔图，对平衡分支的稳定性和突变点进行了分析。结合高超声速飞行器大包线飞行特性，求解并分析了双参数分岔，并计算了稳定分支曲面和不稳定分支曲面，从全包线范围揭示了高超声速飞行器大攻角失稳特性。为了实现高超声速飞行器的稳定控制，基于非线性动态逆和分阶思想，设计了非线性控制器，并计算了非线性开环闭环系统的全局特征根分布，结合所提出的一种基于连续算法的非线性闭环系统全局性能评估方法，评估并分析得出非线性控制器的有效性和较优的全局性能。最后，对闭环系统进行了时间历程仿真，进一步验证了非线性控制器的有效性。

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.