Relay manoeuvre based fixed-time synchronized tracking control for UAV transport system

In this paper, we address the problem of parcel distribution with Unmanned Aerial Vehicles and propose a new Aerial Transport System (ATS) that uses drone relays to enable effective parcel delivery to its destination. In particular, a leader-follower synchronization technique scheme is presented for drone rendezvous and consists of forcing one drone (leader) to be above the other (follower) for parcel relay. In this scenario, no assumptions on the availability of a dynamic model for the leader drone are made, only its position and attitude are available for feedback to the follower drone. Considering the effect of unknown variation of the parcel load, a finite-time tracking control algorithm via output-feedback is designed for the follower drone while guaranteeing that the input constraints for the drones are satisfied. To conquer the challenge faced with the underactuation property of the drone, a decoupling method is adopted in order to view the drone UAV as a cascade structure of two fully actuated subsystems. A fixed-time sliding mode surface is therefore utilized in the control procedure of the attitude tracking of the drone to cope with the disturbances and model uncertainties. Rigorous theoretical analysis is provided to prove that the tracking error of the closed-loop system converge in a finite time. Simulation results are given to demonstrate the effectiveness of the proposed control strategy. (C) 2020 Elsevier Masson SAS. All rights reserved.