| A new inspection method of power transmission line has been appeared based on quadrotor aircraft in recent years. Due to the short flight duration is seversely limited by the battery capcity, one way to relieve the situation is increasing the capcity of battery. However, the increasing of flight time is nonlinear to the increasing of capcity. Besides, the production cost limits the flight time as well as battery technology. So, it's cannot fundamentally solve the problem of a long time autonomous power line inspection. Therefore, this paper proposes an autonomous charging system for the power line inspection quadrotor aircraft.To be first, this paper introduces the composition frame and the system solutions. The system is mainly composed of the ground control station, the patrol aircraft and the charging station network. When the aircraft detects the battery needs charging during the whole inspection process, it will navigate autonomously to the target charging station based on the strapdown inertial and GPS integrated navigation system. Then complete the precise docking through visual navigation. After this, charging station transfer the power wirelessly to the aircraft battery based on class E power Amplifier. And the quadrotor returns to continue to inpsetction when the charging is over.Secondly, it makes research to the related contents of integrated navigation system. Combined with the feature of continuous but divergent error of strap down inertial navigation and the characteristic of bounded but discontinuous error of GPS navigation, it uses extended Kalman filter to fuse navigation data, thus determine the navigation filtering algorithm.Thirdly, it introduces the design of visual navigation and docking. Makes the overall process of visual navigation and describes the designation of the landing beacon as well as the fundmental contents of visual docking. And then interprets the feature detection process of landing beacon, which using Hough transform, Harris corner detection algorithm to achieve the characteristic detection of laning beacon, and the relative position algorithm.To be next, this paper focuses on the design of wireless charging based on class E amplifier. The charging scheme based on electromagnetic induction transmission and power amplifier inverter circuit is determined through the description and comparison of several kinds of wireless energy transmission mode and inverter circuit. According to the theoretical analysis of the class E amplifier wireless power transfer, a parameter design method based on optimal load has been puts forth, and the circuit is simulated in Saber and the wireless transfer efficiency can as high as 90.81%.Lastly, the paper introduces the hardware realization of this autonomous charging system and the experiment of wirless charging. The charging efficiency is approximate to 75%, and the experimental results are consistent with the theoretical and simulation results. Meanwhile, puts forward the existing problem in current system and the direction for future improvement. |
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