Trajectory Optimization for the Vertical Landing Phase of Reusable Launch Vehicles Via Convex Approach

Abstract

AbstractFor better computational efficiency, this paper proposes a convex algorithm to solve the online trajectory optimization problem for the vertical powered landing flight phase of vehicles. To recycle the stages of launch vehicles and lower the cost, vertical take-off/vertical landing reusable launch vehicles are widely studied, actually the precision of the powered landing phase is very important for the recycling mission. In this paper, to achieve both the high precision of landing and the high efficiency of online computation, the convex optimization approach is applied to settle the trajectory optimization problem. Firstly, according to the dynamical model, constraints and mission requirements, the trajectory optimization problem of the vehicles is formulated. Secondly, the flip-Radau pseudospectral discretization approach, lossless convexification, and successive convexification technology are employed to convert the original nonconvex problem to a series of convex problems, and these subproblems can be solved by the primal-dual interior-point method (IPM) accurately and rapidly. The computational procedure of the IPM is also given in detail in this paper. Finally, numerical simulation experiments are given, which prove the computational efficiency and accuracy of the presented convex optimization method.KeywordsTrajectory optimizationConvex optimizationConvexificationPrimal-dual interior-point method