Autonomous Landing of Fixed-Wing UAV in Net suspended by Multirotor UAVs - A Fixed-Wing Landing System
Abstract
This thesis presents an autonomous landing system designed for an fixed-wing unmannedaerial vehicle (UAV) to land in a net suspended by multirotor UAVs. Ordinary landingof an fixed-wing UAV usually involves landing on a long runway, but by landing in anet suspended below multirotor UAVs, operations with fixed-wing UAV can be performedfrom ships or other platforms with confined space where no runway is available. The focusin this thesis is placed on the fixed-wing UAV part of the landing, and involves design andimplementation of a guidance and control system, together with a system for coordinatinga landing path between the fixed-wing UAV and the multirotor UAVs.The autonomous landing system uses the Pixhawk autopilot for low-level control, and asoftware toolchain from Underwater Systems and Technology Laboratory (LSTS), Porto,for high-level guidance and control, mission review and communication. The guidanceand control system developed in this thesis is implemented in the LSTS toolchain, andconsist of a decoupled lateral and longitudinal line-of-sight (LOS) guidance scheme forpitch and roll angle commands, and a speed controller for throttle command.The system is tested both in software-in-the-loop (SITL) simulations and flight experimentsat Agdenes airfield, where successful tests demonstrated both the feasibility and thegood performance of the system using a Skywalker X8 fixed-wing UAV.