Cooperative Aerial Slung Load Transportation Using a Novel Adaptive Sliding Mode Controller

This paper presents a decentralized approach to transport a cable suspended load using multiple Unmanned Aerial Vehicles (UAVs). The proposed approach is decentralized in the sense that the trajectory for each of the UAVs is computed offline using the kinematics of the system and the desired path of the load. This approach enabled the task of cooperative transportation to be treated as a problem of multiple UAVs, each carrying a cable suspended load. A neural adaptive sliding mode controller proposed by the authors in an earlier work is then deployed on each of the UAVs to track the trajectory while minimizing the load swing. Since the system of an UAV carrying a suspended load is underactuated, the conditions on the sliding surface variables that ensure the stability of the system are also given. The performance of the proposed approach is tested with payloads of non-uniform density and uncertain mass, using Gazebo simulations. The performance is compared against an adaptive sliding mode controller which motivated the design of the proposed controller.