关键词: 再入轨迹规划, 序列凸优化, 球状禁飞区, 信赖域, 线搜索

Abstract: To address the reentry trajectory planning problem for hypersonic vehicles with spherical no-fly zone (NFZ) constraints, this paper proposes a sequential convex optimization approach based on dynamic objective reconstruction and a hybrid step-size control strategy, enabling proactive NFZ separation assurance. First, a potential function is introduced to model the spherical NFZs as soft constraints, transforming the reentry trajectory planning problem into a sequence of convex subproblems with coupled soft and hard constraints. Second, to mitigate numerical overflow issues caused by the potential function and reduce sensitivity to initial guesses, a two-phase “feasibility–optimality” dynamic decoupling framework is developed. The first phase focuses on computing a feasible solution to generate a high-quality initial trajectory for subsequent optimization, while the second phase dynamically reconstructs the optimization objective using the soft-constraint potential function to maximize the standoff distance from NFZs without significantly compromising primary performance objectives. Furthermore, a hybrid step-size control strategy is designed by integrating the trust-region method with the line-search algorithm, effectively ex-ploiting descent information from rejected steps and improving computational efficiency. Numerical simulations demonstrate that the proposed algorithm guarantees a sufficient safety margin from spherical NFZs, achieving a 95% improvement in computational speed and reducing terminal altitude and velocity errors by factors of 19 and 6, respectively, compared with the conventional trust-region convex optimization method. Moreover, relative to the Gauss pseudospectral method, the pro-posed approach achieves a threefold increase in computational speed while maintaining comparable terminal altitude and velocity accuracy, highlighting its promising potential for practical applications.

Key words: Reentry trajectory planning, Sequential convex programming, Spherical no-fly zone, Trust region, Line search