TY - JOUR T1 - Developing a hybrid algorithm to design the optimal trajectory of reentry vehicles TT - تدوین یک الگوریتم مشارکتی برای طراحی مسیر بهینه اجسام بازگشت پذیر JF - mdrsjrns JO - mdrsjrns VL - 14 IS - 13 UR - http://mme.modares.ac.ir/article-15-949-en.html Y1 - 2015 SP - 143 EP - 152 KW - hybrid optimization KW - shooting method KW - Reentry KW - Radu pseudospectral N2 - Optimal trajectory planning is an important task which is required in most of guidance missions. This paper introduces a new method that utilizes the most important characteristics of global optimization methods along with a new gradient-based method in a two layered scheme for the trajectory planning. In the first layer to construct a convenient shooting method based algorithm, some of the most important global methods of optimization are used in an information transform structure. Exchanging the information between selected algorithms helps for increasing the efficiency of problem solving. To do this, a comprehensive model for parameterization of the control history is introduced which allows the method to search for the best profile in a variety of different profiles. Results of this layer are transformed to the second layer that uses one of direct methods of solving the optimal control problems. This gradient based method named Radau pseudospectral method using of the results of global methods, completes the optimization process. Finally, developed algorithm is used to find the optimal trajectory of a reentry capsule and effects of the path constraint values on the total heat absorbed is investigated. M3 ER -