Development And Test Of Large-Load Plant Protection UAV Based On Ozonated Water

With the development of green prevention and control technology,ozonated water has been gradually applied in the field of agricultural plant protection.Ozonated water has the characteristics of no pollution,no pesticide damage,and no drug resistance.At present,researchers have conducted in-depth research on backpack,fixed,and vehicle-mounted ozone plant protection equipment.With the rapid development of the agricultural aviation industry,it also provides a new idea for ozone-water plant protection.This paper carried out the development of a large-load plant protection UAV that can prepare and spray ozonated water in real time.Aiming at pest larvae and common diseases caused by agriculturally harmful microorganisms such as bacteria and fungi,a high-efficiency,light,and simple ozonated water preparation and spraying system has been developed that can increase the concentration of ozonated water to 17.3 ppm within 4.5 minutes.On this basis,the ozonated water preparation and spraying system was integrated with the UAV flight platform,and a prototype was produced for performance testing and field verification.The main research content and results of this paper are as follows:(1)A set of ozonated water preparation and spraying systems suitable for plant protection operations was developed,the overall design of the system was carried out,and the ozone preparation device,gas-liquid mixing device,and spraying device were selected.Finally,the influence of different process parameters on the concentration of ozonated water was explored.In the preliminary test,the concentration of ozonated water prepared by this system was up to 17.3 ppm,which can meet the requirements for the prevention and control of pest eggs and common diseases caused by agriculturally harmful microorganisms such as bacteria and fungi.(2)A six-rotor electric plant protection UAV that can be mounted with an ozonated water preparation and spraying system is designed.Its main performances are: maximum take-off weight 58.3kg,battery capacity 44000 m Ah,full-load hovering time 10.2 min,and flight operation time 6.7 min.According to the proposed design goal of the large-load plant protection UAV,the overall design and structural layout design of the UAV are carried out,the power system is selected,and the lithium battery of the power supply system is selected and calculated.Perform static analysis and prestress modal analysis on the fuselage structure of the UAV.The maximum stress of the fuselage is 26.213 MPa,which meets the allowable stress conditions.The vibration frequency of the propeller varies between 70.6 Hz and 83.7Hz,avoiding the natural frequency of the fuselage mode.The fuselage will not resonate,and the structure of the drone fuselage is reliable.(3)A large-load plant protection UAV control system based on ozonated water was developed.The control system integrates flight control with ozonated water preparation and spraying control through the Onboard SDK.The STM32 single-chip microcomputer is used as the control core of the ozonated water preparation and spraying system,and the control mode of remote start of the ground remote controller is used for ozonated water preparation and spraying operations.(4)Trial production of a large-load plant protection UAV based on ozonated water was carried out,the performance test of the prototype was completed,and field verification tests were carried out.Prototype performance tests include an ozonated water concentration test,a hover performance test,a flight performance test,and an effective spray width test.The test results show that the concentration of ozonated water prepared by the prototype reaches its highest level at 4.5 minutes,and the highest value is 17.1 ppm.The hovering time of the prototype under full load and no load is 10.2 minutes and 19.9 minutes,respectively.The hover thrust under full load is about 40%,and the power redundancy is sufficient.When a single power system fails,it can still fly and land stably.The flight operation time of the prototype under full load conditions is 6.7 minutes.When the working height is 2.0 m and the flight speed is 3.0 m/s,the effective spray width of the prototype is 5.25 m.The field control effect test results show that the use of the UAV to spray 17.1 ppm ozonated water for7 consecutive days can prevent grape downy mildew up to 69.7%,which can effectively control grape downy mildew.Using the UAV to spray 17.1 ppm of ozonated water for 7consecutive days,the control effect on broccoli diamondback moth larvae can reach 76.4%,which can effectively control the pest.