直线参考轨迹制导律推导与应用

Derivation and application of guidance laws of a straight-line reference path

针对直线参考轨迹的截获和跟踪问题,提出了一种新的飞行器轨迹制导律设计方法。通过建立轨迹偏差运动方程和一系列坐标转换,利用非线性动态逆(NDI)、增量非线性动态逆(INDI)和PID控制方法推导出制导指令。借助于投影张量和矩阵伪逆等数学手段,使得公式推导过程更加简洁和容易理解,物理概念也更加清晰。针对常见的以法向过载制导律作为内回路输入指令时仿真效果不佳的问题,推导出了以俯仰速率制导律作为内回路输入指令的制导方法,可显著改善制导性能。最后,将所提方法应用于某飞机的高度模态和进近阶段的航向信标(LOC)/下滑信标(GLS)制导律设计,并进行了初步仿真验证。研究结果表明,所提出的制导律能够实现精确轨迹制导,具有较好的动态特性和鲁棒性。

This paper presents novel guidance laws of a flight vehicle to capture and track a straight-line reference path.Through establishment of trajectory error dynamics and transformations of coordinate systems,the guidance laws are derived using Nonlinear Dynamic Inversion(NDI),Incremental Nonlinear Dynamic Inversion(INDI)and PID methods.With the aid of math means such as projection tensor and pseudo inverse of the matrix etc.,derivation progress of proposed formula is more concise and the physical concepts are clearer.To improve the poor flight quality when adopting the load factor guidance law as input command of inner-loop controller,the pitch rate guidance law is deduced and could significantly enhance the guidance performance.Finally,the proposed scheme is applied to the guidance law design of altitude mode and LOC/GLS mode for an aircraft,and the preliminary simulations are conducted.The research results show that the guidance laws designed according to the proposed scheme can achieve precise trajectory tracking and demonstrate satisfactory dynamic characteristics and robustness.