研究高超声速飞行器在纵向的运动情况，对系统的速度和飞行高度进行仿真分析，我们将对在不同的 、 值的条件下分析出系统的最优性能(The longitudinal motion of the hypersonic vehicle is studied, and the system speed and flight height are simulated. We will analyze the optimal performance of the system under different conditions and values.)