Autonomous Control for Orographic Soaring of Fixed-wing UAVs

We recently created a new algorithm for drones to perform autonomous orographic soaring only by means of elevator control, so *without* any use of the throttle. Specifically, since the drone only has one degree of freedom, we gave it as single objective to steer towards a “target gradient line”. Choosing this line requires minimal knowledge on the flow field; only that downwards on the line there should be a high updraft and upwards the updraft should diminish. With drone experiments in a windtunnel, we show that steering towards this line with the elevator results in the drone stabilizing in a zero-excess-updraft area. The drone can almost stay there indefinitely as the elevator actuation costs negligible energy compared to the throttle. The method can also adapt to a changing wind-field, which we tested in the windtunnel by changing the slope of the wooden board. Scientific article: