空射运载火箭轨迹/穿越距离优化设计

Optimization Method of Trajectory/Crossing Distance for Air-launched Vehicle

空射运载火箭轨迹设计受载荷、载机安全性、姿控能力等多因素限制,为了解决空射运载火箭面临的复杂多约束条件下的轨迹优化问题,提出了一种考虑穿越距离、最大载荷约束、最大控制能力的轨迹优化设计方法。建立了机箭穿越距离模型与载荷计算模型,通过将上述模型转换为过程约束引入轨迹优化问题中,利用伪谱法对轨迹优化问题进行求解,从而实现多约束条件下的空射运载火箭上升段轨迹快速优化。在此基础上,梳理了空射运载火箭轨迹设计中影响火箭穿越距离、最大载荷的典型参数,分析了参数间的制约关系。仿真结果表明:该方法能够实现多约束条件下的空射运载火箭上升段轨迹优化,为空射运载火箭研制提供参考;从降低火箭最大飞行载荷以及总体性能提升角度考虑,空射运载火箭应在较高高度进行投放,投放后以最大角速率将攻角调节至最大值,保证火箭快速穿越稠密大气,同时应尽可能缩短穿越距离,避免火箭在低空加速。

The trajectory design of air-launched vehicle is limited by many factors such as load,carrier safety,attitude control capability,etc.In order to solve the trajectory optimization problem under complex and multi-constraint conditions,an optimize method considering the crossing distance,maximum load and maximum control capability constraints was proposed.The crossing distance model and load calculation model of the aircraft and launch vehicle were established.By transforming the above model into process constraints and introducing them into the trajectory optimization problem,the pseudo-spectral method was used to solve the trajectory optimization problem,so as to realize the rapid optimization of the ascent trajectory of the air-launched launch vehicle under multiple constraints.On this basis,the typical parameters affecting the rocket crossing distance and maximum load in the trajectory design were sorted out,and the constraints between the parameters were analyzed.The simulation results show that the method can realize the trajectory optimization of the ascent phase of the air-launched vehicle under multiple constraints,and provide a reference for the development of the air-launched vehicle.From the point of view of reducing the maximum flight load of the rocket and improving the overall performance,the air-launched vehicle should be launched at a high altitude.After the launch,the angle of attack should be adjusted to the maximum at the maximum angular rate to ensure that the rocket can quickly pass through the dense atmosphere.At the same time,the crossing distance should be shortened as far as possible to avoid the acceleration of the rocket at low altitude.