Experimental Study On Safe Flight Distance Of Unmanned Aircraft Bridge Disease Detection And Stability Image

Bridges play a key role in road traffic.The health of the bridges is directly related to the safety of people's lives and property.In order to solve the limitations of existing bridge inspection vehicles not suitable for various types of bridges,serious obstacles to traffic and high cost of use,scholars have begun to extensively research and use UAV airborne equipment for bridge detection in recent years.Due to the aerodynamic effects during flight,the imaging stability is affected,and the lack of safe flight protection is a problem.Therefore,it is very important to study the minimum safety distance of bridge stability imaging for unmanned aerial vehicle.Based on the market configuration,this article optimized the EHM-6V unmanned aerial vehicle with a reasonable aerodynamic layout,large load capacity,medium size,and strong endurance.After a comprehensive comparison,a Sony ILCE-7RM2 camera(the pixel is 40 million,the weight is 548g)is selected,which is equipped with a Sony FE 85 mm F1.8 lens and a three-point laser rangefinder triggered synchronously with the camera shutter.This integrated the bridge detection system of UAV,which provide a reliable experimental basis for subsequent studies.After extensive access to data and wood model design of simply supported beam and arch bridge,unmanned aerial vehicle arrived at the bridge to conduct the flight wind tunnel experiment.Paste the mark points at the lens,the IMETRUM non-contact measuring instrument is used to measure the displacement of the camera marker under the hovering state,and the holding time of hovering state is determined by the continuous state of the displacement.The Modulation Transfer Function(MTF)is introduced to evaluate the imaging quality when unmanned aerial vehicle approaching the bridge model.The minimum safety distance of stable imaging for unmanned aerial vehicle is ensured by combining with the holding time of hovering state and the stability of imaging quality.The actual bridge detection test was conducted,and the flight test of the simply-supported beam bridge and arch bridge was conducted under different wind speeds outdoors,and the experiment results of wind tunnel were verified.By conducting wind tunnel experiments of UAV in the laboratory and on site,we can ensure the safety of stable imaging for bridge detection of UAV.This provides guidance for similar disease identification of the subsequent detection industry.To a certain extent,the borrowing parameters are provided for the UAV manufactures to improve the performance of hardware and software,which has profound development potential and engineering application value.