Research On Transmission Line Safety Distance Inspection System Based On UAV Vision

Transmission line inspection of UAV has become the main way of the electric power lines inspection in State Power Grid Corporation with the advantages of high degree of automation, wide application scope, high efficiency and low cost. The fixed-wing UAV inspection mode is usually used as a quick scan of the transmission line corridor. The multi rotor UAV inspection mode is used for transmission lines precision inspection in short distance because of its flight stability and operability.According to the functional requirements of multi-rotor UAV transmission lines inspection system, the four-rotor UAV inspection system model is established in this paper. Analysis of the structure and function of each subsystem to determine the device selection, and the four rotor UAV transmission line inspection hardware platform are built, and the stability of the platform is verified through the test flight.For the homography transformation between the image and the two-dimensional scene in the visual inspection system, the solution method based on the vision imaging model of transmission line is proposed. The external parameters matrix of the camera and the normal vector of the two-dimensional scene planes are calculated by the transmission line visual imaging model. The intrinsic parameters of the camera are obtained by camera calibration. So the corresponding homography transformation matrix can be obtained. The above method can realize the conversion between the different angle of view image and improve the accuracy of the image measurement of the inspection system. Experimental results show that the homography matrix based on this model can achieve accurate homography transformation.Finally, In view of the requirement of transmission line safety in the process of transmission line inspection by UAV, the four rotor UAV inspection system is taken as the research object, and the method of inspection safety distance measurement based on monocular vision is proposed. Based on the transmission line visual imaging model and the actual height of the towers, the real-time safety distance from transmission lines to the UAV is calculated by the recognition and measurement of transmission line tower image. The correctness of the algorithm is verified by experiments, and the various factors that affect the measurement accuracy and the range of error are analyzed, and the feasibility of the algorithm is verified.