Adaptive Super Twisting Sliding Mode Control For Flying-Wing UAV

Fixed-wing UAVs have received great attention in the military,commercial and civilian fields due to their strong endurance,fast cruising speed,and strong load capacity.The flying-wing UAVs cancelled the vertical tail and flat tail,which making the overall configuration of the UAV smoother,and can provide superior stealth performance and good aerodynamic shape,thus making flying-wing UAVs a hot field of research.But at the same time,the cancellation of the vertical tail and the flat tail will result in insufficient static stability of the UAV.Some rudder surfaces of the wing need to be used to control the pitch,yaw and roll at the same time,which brings difficulties to the control of the UAV.Therefore,this paper studied the attitude control and landing control problems of flying-wing UAVs.Specifically,the following researches were mainly carried out:Firstly,a sliding mode control method is used to control the attitude of the UAV.First,the controller is designed using the non-singular terminal sliding mode method,and then combined with the super-twisting algorithm,an adaptive super-twisting non-singular fast terminal sliding mode controller is designed.Through simulation verification,the designed super-twisting sliding mode controller obtain a good control effect and robustness.Secondly,aiming at the problem of autonomous landing,a landing control system for flying-wing UAVs is designed.First,analyze the entire landing process and divide it into longitudinal and lateral control respectively.In the longitudinal direction,the total energy control system is used for decoupling control of the height and speed,and combined with the total energy control,the control law of the descent process and the flare maneuver process is designed;in the lateral direction,the L1 guidance algorithm is used.Finally,combined with attitude control law,the landing control system of flying-wing UAV is designed.Finally,a hardware-in-the-loop simulation platform was built,and the attitude control algorithm and landing control system were simulated.First,the attitude control algorithm is built in Simulink,and then the algorithm is written into the Pixhawk control board through co-simulation.Then combined with Gazebo simulation world and QGround Control ground station,a semi-physical visual flight simulation was carried out.The results proved that the attitude control algorithm has a certain practicability,and the landing control system can control the safe landing of the UAV.