基于轨迹线性化控制的再入轨迹跟踪制导

针对高超声速飞行器再入制导问题,提出了一种基于轨迹线性化控制(TLC)方法的轨迹跟踪制导律.利用再入飞行器动力学固有时间尺度分离的特点,通过外环路和内环路的设计分别对高度和速度进行控制.轨迹倾角被用作外环路的虚拟控制量来控制高度;倾侧角和迎角用于在内环路跟踪轨迹倾角指令和速度.在反馈回路通过设计线性时变控制器对误差动态进行镇定.反馈增益可在线计算并能符号化地表示为参考轨迹的函数,从而避免了增益插值调度和可能需要的模式切换.大量仿真结果表明:TLC可以实现轨迹的精确跟踪且控制参数对不同参考轨迹的依赖性很小;TLC与基于轨迹在线生成的制导方法的结合可以显著提高再入制导的自主性和适应性.

Trajectory linearization control based tracking guidance design for entry flight

A novel use of trajectory linearization control (TLC) method was introduced in the guidance law design for hypersonic vehicle entry flight. By exploiting the inherent characteristics of time scale separation of entry vehicle dynamics, altitude and velocity could be controlled separately via outer and inner loop design. In the outer loop, path angle was used as pseudo-control for controlling the altitude. In the inner loop, the flight path angle command and velocity were tracked using bank angle and angle of attack as controls. A linear time-varying controller was designed for the feedback loop to stabilize the error dynamics. Feedback gains were computed online and are the symbolical functions of reference trajectory, therefore no explicit gain scheduling or mode-switching were needed. Extensive dispersion simulations show that this guidance algorithm can achieve precise trajectory tracking and is trajectory-independent. The simulations also show that an integrated entry guidance approach which combines the use of TLC-based tracking guidance law design and on-board reference trajectory planning can significantly enhance the autonomy and adaptability of entry flight.