Control Framework for Take-Off of UAVs with Suspended Load in Pipeline Inspection

This paper presents a control framework for the retrieval operation of an inspection crawler from a pipeline, using an UAV (Unmanned Aerial Vehicle) with a cable. The inspection crawler inspects the pipeline until it is retrieved using the UAV with a cable. In order to create this control framework, the task has been divided in two different phases: the tethered UAV phase and the flight of the UAV with a suspended load. For each phase, we study the dynamic and we propose a specific controller. The control framework is composed of a controller obtained using the feedback linearization technique for the tethered phase, while the controller of the second phase is based on an IDA-PBC (Interconnection and Damping Assignment-Passivity Based Control) controller. The proposed control framework is validated through simulations in Matlab-Simulink, showing that the UAV can properly recover the inspection crawler from the pipeline and stabilizes with the crawler as a suspended load at a new position.