Trajectory Optimization for Ascent and Glide Phases Using Gauss Pseudospectral Method

The trajectory optimization method for ascent and glide phases' flight of a hypersonic vehicle is studied.In addition to the constraints on the final position coordinates, the final orbit position and velocity are specified.This article presents also the purpose of designing the endpoint and the constraints during the fight until the endpoint.The trajectory optimization is divided into two phases: vertical-rise phase and orbit-insertion phase respectively.The trajectory optimization problem is formulated as the multi-constraints optimal control problem.Gauss Pseudospectral Method (GPM) method, it is converted into the nonlinear programming which is solved by SNOPT.This direct optimization technique uses linkage constraints to enforce state and optimization parameter continuity between phases.The independent phases, linked together, allow for a common cost or objective function to be optimized.The derivative of reference angle of attack is chosen as the control variables, the performance index is the weighted sum of squares of this derivative.Results show that the proposed method able to iteratively provide the solution coming closer to the necessary condition for optimality and terminal constraints.