An Integrated Method for Landing Site Selection and Autonomous Reactive Landing for Multirotors

Unmanned Aerial Vehicles (UAV) in autonomous operations is an emerging technology with growing applications in several areas, such as agriculture, search and rescue (SaR), and even space exploration. The take-off and particular landing are some of the critical parts of operation. This paper proposes a landing site selection and control algorithm for an autonomous multirotor UAV. The goal is to land the UAV in safe locations as close as possible to a Point of Interest (PoI), mainly in unknown and unsafe terrains. The Landing Site Selection (LSS) algorithm uses terrain features from a 3D pointcloud, Support Vector Machines (SVM) to classify landing safety, and a cost function to compute the best landing site. The algorithm can be used both offline with a 3D map and online with data from a depth sensor. The states of the landing procedure are handled by a high-level state machine and velocity controllers control the UAV. LSS was tested using 3D maps of real scenarios and data from depth camera mounted on a real UAV, and the full autonomous landing system was tested in a simulated environment.