高超声速飞行器非线性纵向运动稳定性研究

针对研究高超声速飞行器飞行动力学稳定性时忽略方程非线性影响的问题,建立了保留非线性特征的六自由度动力学方程组和非线性活塞理论耦合模型。研究了初始迎角和活塞理论非线性项对高超声速飞行器纵向稳定性的影响,并在稳定巡航中施加瞬时扰动,分析其姿态响应。仿真结果表明:高超声速飞行器姿态收敛速度比常规低速飞行器慢很多;对迎角施加扰动后,飞行器姿态变化主要影响短周期模态,且偏离平衡位置越远,收敛越快;改变气动力非线性项时,其姿态变化主要影响长周期模态,且收敛较慢;两种扰动均对振荡周期无明显影响。

Research on nonlinear longitudinal motion stability of hypersonic vehicle

For the problem of ignoring the nonlinear effects of equations during study the stability of flight dynamics for hypersonic vehicle, the coupling model of six-degree-of-freedom dynamic equations and nonlinear piston theory that retains nonlinear characteristics was established. The effect of initial angle of attack and piston theory nonlinear term on longitudinal stability was studied. Transient perturbation was applied while the hypersonic vehicle was cruising stably, and its attitude response was analyzed. Simulation results show that hypersonic vehicle’s attitude convergence speed is much slower than conventional low-speed vehicle. When the angle of attack is disturbed, the vehicle attitude change mainly affects short-period mode. The farther from the equilibrium position, and the faster the convergence becomes. When the aerodynamic nonlinear term is changed, its attitude change mainly affects the long-period mode, and the convergence is slower. Both disturbances have no significant effect on the oscillation periods.