Optimization of vertical profile trajectory for unmanned aerial vehicle
无人飞行器纵向剖面轨迹优化

In optimizing the vertical profile trajectory by energy method, we choose the fuel-efficient performance index for a given distance as the cost function and build a three-stage trajectory-optimization model. Being different from traditional methods that optimize the speed, while keeping the engine thrust in constant, this method optimizes both the engine thrust and the speed simultaneously. The three-stage trajectory-optimization model combined with the real flight process of the unmanned aerial vehicle is transformed into a nonlinear programming problem to be solved by using the restart FR (Fletcher-Revees) conjugate gradient method. Simulations have been carried out on the unmanned aerial vehicle model. Results show that vertical profile optimal trajectory obtained by the proposed algorithm saves more fuel than that obtained by keeping the engine thrust in constant. The superiority in fuel-saving and cost-reduction is significant.