Study On Performance Of Plant Protection UAV Spray Performance Test Bed

With the development of science and technology,the plant protection UAV has become the main tool for plant protection operations due to its advantages of flexible operation and pesticide saving.In order to make the plant protection UAV carry out the plant protection operation scientifically and reasonably,achieve the purpose of accurate spraying and reduce the use of pesticides,many companies and scientific research institutions have developed the spray test platform of the plant protection UAV according to different needs to test the spray effect of the plant protection UAV.However,there are relatively few researches on the precision,operation method and stability of the spray test bed in China.Based on the original spray performance test bed,this paper conducted experimental research on the test accuracy,operation method,stability and expansion function of the test bed.The specific research contents and results are as follows:1.Study the test accuracy,determine the correction coefficient and summarize the operation method.Through the test,the error analysis of the spray performance test rig is carried out.The frequency of the fan is 40 Hz and the test time is 3min.For the best test condition of the test-bed,the correction coefficient calibration test is carried out under the best test condition.The correction coefficient is 0.03 L through calculation and analysis of the test data.The maximum relative error is 0.72%;The maximum relative error of stability is 1.8%.The applicable conditions and operating procedures of the test-bed are summarized and analyzed,and the standard operating procedures are formulated.According to the standard operating procedures,the test error can be controlled within 1%.2.Develop the function of the spray performance test bed,and develop a new measurement method of effective spray amplitude through the determination method of 50% effective deposition amount.Ansys Fluent was used to simulate the path of spray droplets emitted from the nozzle to calculate its effective spray amplitude.The two were compared and analyzed to verify its accuracy and feasibility.The effect of different spray pressure and spray height on the effective spray amplitude is studied.It is found that with the increase of spray height,the effective spray amplitude increases first and then decreases.When the spray height is 2m,the maximum effective spray amplitude of the nozzle is 1.2m,and the spray pressure has no significant effect on the effective spray amplitude.3.Spray performance test stand is used,standard operation method is adopted,and response surface analysis method in Design Expert 11 software is adopted.The spray characteristics of NJY-1260 octorrotor plant protection UAV under different spray height,rotor speed and spray pressure,such as effective spray amplitude,drift rate and coefficient of variation,were studied.Through the analysis of test data,the results show that the spray pressure of0.25 MPa,rotor speed of 5000r/min,spray height of 1.62 m are the best operating parameters.