Overall Design And Control System Design Of A Tri-Tilt Rotor Unmanned Aerial Vehicle

Hovering unmanned aerial vehicles,including helicopters,multi-rotor UAVs and tilt-rotor UAVs etc.,have been widely studied and used due to their hovering capability.Tilt-rotor UAV,which possesses both merits of multi-rotors(vertical takeoff and landing)and fixed UAV,is becoming a hot point.In this thesis,a novel UAV configuration with three tilt-rotors(hereinafter referred as TTR)is proposed based on design requirements,with airfoil selected and aerodynamic performance calculated.The mathematical model of the UAV is derived for flight control system design based on the flight features.The TTR UAV has three flight modes: multi-rotor mode,fixed wing mode and transition mode.During the transition flight process,it has manipulation features of both multi-rotor and fixed wing UAVs,resulting in strong coupling characteristics and high nonlinearity.Therefore,smooth transition is the key to flight control of TTR UAV,and it is the focus of this study.A flight control system employing classic PID method for control laws was designed,with simulation performed and both hardware and software developed.Flight tests were performed with a prototype manufactured.The results of simulation and flight test show that the TTR UAV designed meets all requirements and the control scheme is feasible with robust control performance.