High-Dimensional Merit-Function-Based Sequential Convex Programming for Nonlinear Trajectory Optimization

This study focuses on the key challenge of achieving high-precision guidance for spacecraft: real-time trajectory optimization. The highly efficient sequential convex programming (SCP) is a potential method to address this issue, but its convergence is difficult to guarantee. To enhance the convergence performance of SCP, this paper proposes a high-dimensional merit-function-based SCP method. The main contribution of this paper is threefold. Firstly, the traditional one-dimensional penalty function used to ensure the convergence of SCP is extended to a high-dimensional merit function, which avoids using the penalty parameter that is difficult to determine in advance. Secondly, to match the high-dimensional merit function, a feasibility-then-optimality convergence strategy is proposed, which is essentially an application of the iterative direction descent property in higher dimensions. Finally, based on the high-dimensional merit function and the feasibility-then-optimality strategy, an iterative algorithm is developed, and its convergence analysis is provided under certain assumptions. In numerical simulations, the effectiveness and robustness of the proposed algorithm are validated using the reentry trajectory optimization problem of a lunar capsule.