Periodic Optimal Flight of Solar Aircraft with Unlimited Endurance Performance

Solar aircraft offer the possibility of an unlimited endurance. This can be achieved if the energy required for the flight at night is stored in batteries. The goal of an unlimited endurance performance is treated as a trajectory optimization problem. This is a problem of periodic optimal flight because the trajectory is repeated after a complete day-night cycle. A trajectory optimization is performed with the objective of minimizing the required battery capacity. Thus, the weight penalty due to the batteries can be kept as small as possible. Realistic mathematical models of the energy management system, the available solar radiation and the dynamics of the aircraft are applied. With the use of an efficient optimization method, solutions of the periodic trajectory optimization problem are generated.