Research On Several Key Issues Of Autonomous Flight Of UAV

With its simple structure and low cost,quad-rotor unmanned aerial vehicle(UAV)has shown great values and development potential in many fields,including target reconnaissance,disaster warning and agricultural plant protection.Additional advantages of UAVs include vertical take-off and landing and easy movement control.In the scenario of photovoltaic inspection,combination of UAVs and ground control station(GCS)could be applied to mission planning,attitude control,and fault analysis of PV modules,which would improve inspection efficiency and degree of automation of the whole system greatly and provide scientific decision support for managers.The thesis focuses on the concrete application of quad-rotor UAV in the field of PV inspection and discussed mission planning,visual aided navigation,autonomous landing and GCS combining with practical problems.The main work and contributions of the thesis are as follows:1)Firstly,the current research status in UAV path planning and visual aided navigation are described systematically,and problems and limitations in the above procedures are analyzed in detail.Aiming at the characteristics of short battery life and limited communication distance of quad-rotor UAV,start point planning method and task assignment algorithms for centralized and distributed PV scenarios are proposed respectively,which can boost the UAV utilization and inspection efficiency.The simulation results verify the effectiveness of the above methods.2)In order to achieve autonomous flight for UAVs in PV farms and complete infrared and visible-light image acquisition,an edge detecting method for PV strings was proposed and line of sight guidance based path following algorithm was carried out according to the distribution characteristics of PV strings.The results show that identification approach for PV strings and line of sight guidance method can work well in localization and navigation respectively,and combination of the two procedures meets the requirements of UAV flight control.3)For the sake of solving the problem of precise landing at designated points for UAVs,landing target model is designed independently according to the basic landing requirements.The relative position and attitude can be estimated by visual feedback in real time,so that the onboard processor can detect the landing guide,calculate offsets and send control instructions.Focusing on the actual requirements of human-computer interaction,ground control station software is designed independently on the basis of C#,which enables the UAV and ground control system to transmit state information and control instructions in real time and both directions.At the end of the thesis,the main work is summarized and the further research is prospected.