基于凸优化的再入轨迹三维剖面规划方法

可重复使用飞行器一般采用大升阻比气动外形，再入轨迹三维剖面规划方法可充分发挥这类飞行器固有的机动能力。计算量大是制约三维剖面规划应用的难题，为提高计算效率，提出了一种基于凸优化的再入轨迹三维剖面规划方法。首先，分析运动方程特性，利用定义新的控制变量、约束松弛、连续线性化等技术，将原始非凸的三维剖面规划问题转化为一个凸优化问题。其次，将指令反解步骤嵌入至序列凸化算法中，通过迭代求解凸优化子问题，获得原问题的可行解。数值仿真结果表明所提方法具有较高的求解精度和确定的收敛性质，飞行器的机动能力得到充分发挥；与伪谱法的结果对比表明凸优化方法在轨迹规划问题上具有更高的求解效率。

Entry trajectory planning method based on 3D profile via convex optimization

The reusable launch vehicle has an aerodynamic shape with a high lift-drag ratio. The entry trajectory planning based on the 3-D profile can take full advantage of the inherent maneuvering ability of the vehicle. However, the heavy computational burden restricts the application of the 3-D profile planning method. To improve the computational efficiency, this paper proposes an entry trajectory planning method based on 3-D profile via convex optimization. The characteristics of dynamic equations are first analyzed, and the original non-convex trajectory planning problem is transformed into a convex optimization problem using convexification techniques such as the definition of new controls, constraint relaxation, and successive linearization. The command solution step is then inserted into the sequential convex optimization algorithm proposed in this paper. A feasible solution is obtained by solving iteratively the convex sub-problem. In the simulation experiments, the high solution accuracy and the determined convergence of the proposed method are demonstrated, and fully utilizing the maneuvering ability. Compared with the pseudospectral method, the proposed method has a significant advantage in computational efficiency.