Reentry skipping trajectory optimization using direct parameter optimization method

In this paper, the application of direct parameter optimization method to reentry vehicle three-dimension skipping trajectory optimization is introduced. Firstly, the model of trajectory optimization control problem to reentry vehicle skipping trajectory is established, while motion equation of the state variables is a three degree-of-freedom model. Performance is selected to minimize the sum of heat, overload and dynamic pressure. The control variables are angle-of-attack and bank angle. During the flight, reentry vehicle is subjected to the heat rate and overload constraints. Terminal state variables constraints are path angle, altitude and latitude constraints. Then, the optimal control problem is discretized into nonlinear programming problem (NLP) using direct parameter optimization method. The control variables are selected as optimal parameters at all nodes. Parameter optimization problem is solved using POWELL algorithm. The simulation result shows that the optimal solutions of skipping trajectory optimization problem are in real-time using direct parameter optimization method. Therefore, direct parameter optimization method is a viable approach to the reentry vehicle skipping trajectory optimization problem.