LAUSR

In conditions with limited power, such as when constrained by the solar-cell efficiency and/or with reduced solar radiation, it is necessary to efficiently manage the flight energy to ensure continuous flight of a solar-powered unmanned aerial vehicle (UAV). In this study, the endurance flight of a solar-powered UAV was improved by optimizing the flight path with the use of the gravitational potential and by controlling the attitude. The energy optimization for the flight endurance was conducted with case studies. The results of the simulation show that the optimal path planning is effective to increase the endurance of a flight. The use of the gravitational potential energy in descending flight during the night can reduce the dependence on batteries and, as a result, contributes the reduction of the aircraft weight and the extension of the flight endurance. Also, since the optimization process is carried out in real time, it can cope with meteorological changes in real time and is especially useful in the low-altitude domain that is easily affected by the weather.