Reentry trajectory optimization of hypersonic vehicle with minimum heat

To support the global reach concept, the hypersonic vehicle is designed to realize the global strike mission. The paper applies the enhancing parametrization method to the reentry trajectory optimization of the hypersonic vehicle. This problem is considered as an optimal control problem with some path constraints, which must be satisfied along the reentry phase. The purpose is to design an optimal control law to ensure that the hypersonic vehicle minimum the heat under the final condition, dynamic pressure and overload constraints. Traditional methods for solving the optimal control problems is to solve the necessary conditions by applying the Pontryagin minimum principle, which is difficult for solving the Two Points Boundary Value Problem since the initial guess of the costate variable isn't tractable. In this paper, the problem is transformed into an equivalent standard optimal control problem subject to continuous state inequality constraints. A computational method is developed based on the control parametrization in conjunction with a time scaling transform and the constraints transcription method. Finally, the results of this parametrization method is compared with that of the conventional one and the heat is reduced by 10%.