Safe Landing of Fixed Wing UAVs

Fixed-wing unmanned aerial vehicles (UAVs) are used in several applications from agriculture to search and rescue. An interesting feature of these vehicles is their ability to deploy by hand and easy recovery with belly landing. However, as the payload of the vehicle increases, they become heavier, and hence these vehicles need to be launched in the traditional manner on a small runway with wheels. The most difficult part of the UAV mission is landing as any deviation from the desired trajectory can lead to a crash. One way to increase the safety of landing is to know when to abort the landing. For this, we need to compute the feasibility region online and determine if the vehicle can achieve the landing or not. If not, then abort landing. We designed a 3D LQR based landing controller that accurately lands the vehicle on a runway and also compute the safety regions to determine safe landing of the UAV. Through extensive simulations, we demonstrate the conditions under which a UAV is able to land safely. Further, we also extend this to linearly moving landing pads.