Abstract: Re-entry trajectory optimization with complex constraints for hypersonic vehicles is a strong nonlinear optimal control problem with multiple phases and constraints. A trajectory optimization framework which adds the constraints successively based on Gauss pseudo-spectral method is proposed. The framework is used to build more accurate models of typical regular no-fly zone to provide multiple choices for mission plan, and then a successive approximation solving method is proposed to simplify the complexity of constraint model. In each iteration, the previous solutions to simpler problems are used as initial guesses to approach the solution of the original problem. Numerical examples for minimizing time of trajectory with multiple constraints including heat flux of stagnation point, overload, dynamic pressure and no-fly zone constraints are simulated to demonstrate the proposed method. The simulation results show that the phased adding constraints trajectory optimization framework has better robustness.

Key words: basic disciplines of aerospace and technology, trajectory optimization, optimal control, no-fly zone constraint, re-entry, Gauss pseudo spectral method