Research On Quad-rotor Autonomous Takeoff And Landing Method In UAV/UGV Heterogeneous System

By the respective advantages of UAV(Unmanned Aerial Vehicle)and UGV(Unmanned Ground Vehicle),heterogeneous systems composed of them can collaborate to accomplish more complex tasks.In the background of rescue mission,this paper proposes a quadrotor autonomous takeoff and landing method for UAV/UGV heterogeneous system.Firstly,the task background of the heterogeneous system is described in detail,and the framework of the heterogeneous system composed of quadrotor and Mecanum wheel car is built according to the task.In order to maximize the original stability of UAV,a control method based on SBUS protocol to simulate remote control(RC)is proposed.In terms of UGV with Mecanum wheel,a detailed description of control method is designed.When quadrotor UAV takes off autonomously,an equivalent fluid model of quadrotor is established and meshed by unstructured grid.Then proper fluid model is analyzed.After setting the boundary conditions,the SIMPLE algorithm is used to calculate the numerical solution of flow field.Then,the velocity and pressure cloud images of the quadrotor are obtained.The data is post-processed in Matlab to analysis the relationship between the ground effect and the flying height of the quadrotor UAV.According to the relationship,the quadrotor autonomous take-off plan is designed.During the process of throwing rescue supplies,the mass of quadrotor will change a lot,so a LQR and model reference adaptive control strategy is proposed for quadrotor UAV.In the simulation,the stability of the proposed control method is verified by comparing the results with other methods.Finally,the whole landing process is divided into three stages: long-range,medium-range and close-range.By using the characteristics of different sensors,GPS/RTK hybrid guidance is used for long-range,UWB guidance is used for medium-range,and visual guidance is used for close-range.In the long-range and medium-range,the scheme of positioning and guidance is described in detail.In the close-range,according to the requirements of UAV landing on mobile UGV,a visual guidance method based on Apriltag is proposed,and the relative attitude and distance between UAV and UGV can be caluclated precisely.In summary,a series of simulations and experiments in this paper show that the takeoff and landing method of UAV is effective and can be realized,and the contribution of this research have great significance for the study of UAV/UGV heterogeneous system.