A binocular vision based auxiliary navigation system of the unmanned aerial vehicle for power line inspection
To achieve the wire-landing and wire-walking inspection of the unmanned aerial vehicle (UAV) for power line inspection, a binocular vision was developed based auxiliary navigation system on the embedded development platform. Based on the specific imaging target, line laser is shine on the power system wire, making it a cooperative target to assist the landing of UAV. During the course of UAV flight, the distance between the wire and mounted binocular ranging device and the angle between the Yaw direction and wire direction can be obtained, which can function as the auxiliary Navigation for UAV and improve the success rate of the landing. In the realization of binocular vision algorithm, the process of extracting characteristic points can be simplified by swiping the wire using laser beam. This can increase the implement speed of the algorithm while maintaining the precision. After the distance is obtained, the angle between the Yaw direction of UAV and the wire direction can be calculated through a simple mathematical model. The results showed that the relative error of binocular distance measurement was 2-3 %. The minimum deviation angle that could be identified with a Yaw direction at 50 cm was 5°. The imaging processing frame rate was 30Hz, which met the accuracy and real-time requirements of UAV landing.