Abstract:

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.

Key words: flight control, optimal terrain following system, linear programming