Rapid ascent trajectory optimization of rocket-based combined cycle hypersonic vehicle

RBCC高超声速飞行器上升段轨迹快速优化

¹ School of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China
² COMAC Flight Test Center, Shanghai 201323, China

Received: 13 September 2022

Abstract

The ascent trajectory design of a rocket-based combined cycle (RBCC) hypersonic vehicle has many typical characteristics, including the complex working mode of the RBCC power system, strong coupling between thrust and flight state, strong nonlinear model and many complex constraints etc. This paper proposes a rapid trajectory optimization method based on sequential convex optimization to optimize the complex ascent trajectory with the RBCC power system. Firstly, a mathematical model for optimizing the ascent trajectory of the RBCC hypersonic vehicle is established to describe the angle of attack control system with and without the second-order lag. Then, the optimization model is made convex and discretized based on the convex optimization theory, and a trajectory optimization strategy is improved. Finally, taking the maximum terminal mechanical energy as optimization objective, the ascent trajectory optimization is simulated in cases with and without the second-order lag in the angle of attack control system. The simulation results show that the proposed mathematical model and the ascent trajectory optimization method are rapid and reliable and that the optimization results meet the characteristics of the RBCC power system and provide reference for the application of a RBCC power system and the design of an angle of attack control system.

摘要

针对火箭基组合循环(RBCC)高超声速飞行器上升段轨迹设计所具有的动力系统工作模态复杂、推力与飞行状态存在强耦合、模型强非线性且存在多种复杂约束限制等典型特征, 设计了一种基于序列凸优化的RBCC动力上升段轨迹快速优化方法。针对攻角控制系统是否存在二阶滞后情况, 分别建立了适用于RBCC高超声速飞行器上升段轨迹优化的数学模型。基于凸优化理论对原优化模型进行凸化和离散化处理, 进而设计了改进的轨迹优化求解策略。以末端机械能最大为优化指标, 针对攻角控制系统存在/不存在二阶滞后的情况分别进行了上升段轨迹优化仿真。结果表明, 所构建模型和轨迹优化方法可以快速、有效地完成RBCC高超声速飞行器上升段轨迹优化, 优化结果符合RBCC动力系统工作特点, 且可为RBCC动力运用和攻角控制系统设计提供参考。