三次样条最佳地形跟随系统的研究

 本文用线性规划法取代二次规划法以实现三次样条最佳航迹的计算,简化了约束条件,且能在原有飞行自动控制系统基础上设计航迹自动跟踪系统,从而大大地减少计算工作量,使得原来无法实现的Funk及Kelly等人的三次样条最佳地形跟随方案十分接近于实时实现条件。混合仿真结果表明。6370m长的最佳航迹可于14.6 s内算完,而飞机飞过这段航迹要用20 s,且这种算法可以保证飞过高度变化范围达1000 m的地形,地形跟随系统的实际高度与参考值的误差不超过10 m,最大法向过载在0～3 g之闻,满足了当前地形跟随系统的基本技术要求。

THE RESEARCH OF CUBIC SPLINE OPTIMAL TERRAIN FOLLOWING SYSTEM

In this paper linear programming algorithm is utilized to compute the optimal cubic-spline flight path instead of quadratic programing approach which was suggested by Dr. Funk in( 1 ). Besides, feedback gains of automatic flight control system are determined with the aid of classical control theory. In this way, the amount of computation is significantly decreased. Results of hybrid simulation show that it takes 14.8 seconds for a PC computer of type "Super" to complete the computation of optimal flight path with a range of 6370 meters, over which 20 seconds are needed for the aircraft to fly. Thus compared with the algorithm of Dr. Fenk's the proposed algorithm makes the real-time computation of the optimal cubic spline flight path closer to practical realization. Further more, the proposed algorithm can ensure an optimal terrain following flight over a terrain with height changes as high as 1000 meters. The maximum error of the resulting terrain following path in comparison with the optimal reference one is less than 10 meters, the normal load falls within the range of 0 to 3g. All the above results show that the designed system satisfies all the requirements specified to the terrain following system.