Research On Pose Detection Of Six-rotor UAV Based On Vision Assistance

Since its flexibility and cheap,UAV is used to a largely extent in various aspects,such as aerial photography,rescue,agriculture and other scenes.As the landing process of UAV is in the stage of high accident incidence,it is particularly important to achieve accurate landing.When the signals of satellite navigation system and inertial navigation system are interfered,new auxiliary means need to be introduced to achieve safe landing.Aiming at the requirement of UAV real-time positioning during landing,with the help of visual tools,the research of UAV visual positioning is carried out in this dissertation.The goal of this dissertation is to realize the real-time detection of UAV pose,and transmit the pose information to the ground.The research contents are as follows:(1)The working principle of the six-rotor UAV is analyzed systematically,and the pose coordinate transformation relationship of the UAV based on the camera imaging model is established.The control methods of UAV pitching,yawing,lifting and rolling are analyzed;The transformation between UAV coordinate system and ground coordinate system is determined;Based on the principle of keyhole imaging,the intrinsic relationships among the world coordinate system,camera coordinate system,image coordinate system and pixel coordinate system of UAV pose in imaging are established.(2)Through the comparative analysis of the advantages and disadvantages of identification codes such as Aruco,ARToolkit and Apriltag,Apriltag identification code is picked as the research object in this dissertation,and the steps of Apriltag detection including line fitting,quadrilateral detection,QR code coding,quadrilateral screening,QR code decoding and label recognition are analyzed systematically.The camera is calibrated by Zhang Zhengyou camera calibration method to obtain the radial and tangential distortion parameters of the camera;the solution process of position problem of six-rotor UAV is analyzed in this dissertation,and the relative position and attitude information between identification code and camera is completed.(3)According to the requirements of position and attitude detection,the overall design of the six rotor UAV position and attitude detection is completed.The model of hardware equipment is determined,the test hardware platform is built,and the software test platform of ROS system based on the graphical function of Rviz is developed.The real-time detecting of position and attitude during landing of six rotor UAV is completed.The relative pose and attitude information of the six-rotor UAV during landing with the identification code is obtained.