Amirreza kosari - Corresponding Author Assistant Professor of Aerospace Engineering, Faculty of New Sciences and Technologies, University of Tehran
Hosein Maghsoudi - Ph.D. student of Aerospace Engineering, Faculty of New Sciences and Technologies, University of Tehran
Puya Gorji - M.S. student of Aerospace Engineering, Faculty of New Sciences and Technologies, University of Tehran

In this paper, the aim is to produce optimal trajectory and optimal control laws for a Parafoil, and to present nearly accurate analysis for a class of nonlinear optimal control problems based on iteration of variations method. The design and optimization of trajectory is analyzed and investigated in various fields like mission design for aerial, marine and terrestrial vehicles including unmanned aerial vehicles, parachutes, submarine robots without Passengers, vessels, ships and Landing Crafts. In this paper, trajectory design of a parafoil has been done using iteration of variations. Here, a method of manufacturing a nonlinear optimal control law is proposed. The main Steps are to formulate the optimal control problem as a problem of two point boundary value based on equations of state and quasi-state equation relating to optimality condition and Hamiltonian function and then solving boundary value problem using iteration of variations. Finally, when the desired solution is reached, the control law can be derived with simple calculations.

Develop optimal trajectory, optimal control, iteration of variations method, parafoil