System Design And Spray Performance Test Of Plant Protection UAV Flight Testing Platform

With the rapid development of the precise agriculture aviation industry,plant protection UAV,as an emerging plant protection machine,has the advantages of low altitude,low capacity,high operating efficiency and so on.Due to the complex operating environment and the limited accuracy of airborne sensors,it is difficult to obtain flight posture,position,or speed information timely when plant protection UAV are operating.Only theory and experience are used to set flight parameters,which affects the effect of precise spraying operations.Therefore,the spraying performance testing of plant protection UAV has become an vital issue,and the development of plant protection UAV performance testing devices is imminent.Based on the analysis of the spraying performance testing platform and the current research status of spraying characteristics technology at home and abroad,this paper builds a plant protection UAV flight experimental platform,using this experimental platform to test the spraying performance of plant protection UAV to replace the complicated Field trials.Here are the main research contents and results of this paper:First of all,according to the overall plan of the plant protection UAV flight experiment platform,use Solid Works to draw a three-dimensional model to design the mechanical structure of the plant protection UAV flight experiment platform,and select the proper type of driver and controller according to the design requirements.The experimental platform has a fixed height,fixed speed,fixed angle of attack function.The track trolley device is equipped with a plant protection UAV for simulated flight,and the maximum speed can reach 10m/s;the plant protection UAV fixture device can adjust the angle of attack 0-30°;the control lifting device can change the distance between the plant protection UAV and the target to be measured 0-5m.Double linear guide rails and adjustable four-wheel eccentric sliders are used.Sensors are evenly distributed at the starting point,deceleration point and finishing point,which play a limiting role in linear motion.Choose a three-phase asynchronous motor,the speed n at full frequency 50 Hz is 980 r/min.Then,using ANSYS Workbench finite element analyses software to conduct static analysis and modal analysis on the overall structure and key components of the plant protection UAV flight experiment platform under different working conditions,and at the same time analyses the track trolley device and the plant protection UAV fixture device.Through the calculated stress distribution and displacement,the mechanical structure design meets the strength and rigidity requirements,and the natural frequencies and vibration modes of each order are calculated to avoid resonance.Finally,the paper carries out performance testing and research on the flight test platform of the plant protection UAV.First,the test platform is debugged,calibrated and safety checked,taking flight speed,aircraft angle of attack,and flight altitude as factors,and fog drop deposition uniformity as evaluation indicators to conduct the experimental research.The paper uses Design-Expert software to analyze the variance of the obtained experimental data and establish the regression equation to analyze the interactive influence of the experimental factors.The results show that the order of factors affecting the uniformity of fog droplet deposition is: flight altitude> flight angle of attack> flight speed,and the optimal operating parameters are: flight speed 3.359m/s,flight altitude 1.002 m,aircraft attack angle 0.893°,The coefficient of variation of droplet density is 23.38%.After the error correction test is carried out,the coefficient of variation of the droplet density is 24.52%.At this time,the uniformity of the droplet distribution is the best,and the relative error is 5%.