RBCC可重复使用运载器上升段轨迹优化设计

针对火箭基组合动力(RBCC)可重复使用运载器(RLV)轨迹多段、多控制变量、推力与飞行轨迹耦合,飞行轨迹设计困难的问题,提出了基于高斯伪光谱方法的数值优化求解模型和求解方法,并获得满足要求的上升段燃料最省轨迹。将该轨迹分为3部分,分别由引射火箭、亚燃冲压和超燃冲压发动机提供动力,以攻角和燃料秒流量为控制变量,根据轨迹任务和各模态发动机启动及工作条件建立优化模型、设定各段末端和路径约束,利用高斯伪谱法求解最优轨迹并利用特殊方法计算边界控制变量。通过与传统方法所得轨迹的对比表明,所建立的优化模型和方法可快速求解出RBCC运载器上升段最优轨迹,优化结果符合RBCC运载器工作特点。

Optimization of ascent trajectory for RBCC-powered RLV

Since the multi-phase and multi-control-variable trajectory of the reusable launch vehicle(RLV)which is coupled with the thrust powered by rocket based combined cycle(RBCC) is difficult to solve,the numerical optimization model and method based on Gauss Pseudospectral Method(GPM) were proposed,and the optimal-fuel ascent trajectory was obtained.The trajectory is divided into three phases powered by rocket,ramjet and scramjet in sequence.The angle of attack and fuel flow are control variables,and according to the trajectory mission,the ignition and work condition of the each mode,the optimization model was built,the terminal and path constraints were imposed.The optimal trajectory was solved by using GPM and the boundary control variables were solved by a special method.Compared with the result by traditional method,the optimization model and GPM can solve trajectory optimization problems effectively,and the optimal result accords with the characteristic of the RBCC-powered RLV and satisfies all the constraints.