Design Of Plant Protection Machine Precise Applicator Based On Machine Vision And Simulation Optimization

As a field management oriented machine in agricultural machinery,the plant protection machine carries out pesticide application tasks on crops in different periods.Due to the phenomenon of excessive spraying and droplet drift in the spraying process,which has caused great harm to operators and the natural environment,the spraying device of 3wpz-2000 plant protection machine is designed and optimized.The main research contents of this paper are as follows:First,in view of the problem that the traditional full coverage spraying method can not reach the surface and play a role in the weeding operation of crops in the seedling stage under the straw collection mode of conservation tillage,which directly causes the waste of chemical solution and environmental pollution.At the same time,in order to improve the uneven spraying of chemical solution caused by the change of driving speed of plant protection machine and crosswind,a precise spraying device is designed to improve the utilization rate of chemical dosage through machine vision processing.The camera mounted on the front end of the plant protection machine is used to collect the straw row field image,segment the straw and seedling belt in the image through the intelligent optimization multi threshold algorithm,correct the boundary edge by morphological methods,select and separate the field seedling belt area with the external moment frame,calculate the centroid position of the seedling belt,and mark the positioning line of the seedling belt.According to the coordinates of the seedling belt positioning line,control the lead screw sliding table of the stepping motor to drive the nozzle to move above the seedling belt to realize the displacement and spraying of the nozzle;Each nozzle is equipped with independent micro electric valve and flow sensor.The M-type double input single output fuzzy controller is used to adjust the spraying amount according to the driving speed and cross wind speed of the plant protection machine to realize variable spraying.The experimental results show that the accuracy of the device for identifying the seedling belt location line is about 85.7%;Co MPared with the traditional full coverage spraying method,the precise spraying method in the straw row mode saves about 62.1% of the liquid medicine;At the same time,the sedimentation uniformity of liquid medicine was also improved and maintained at about 26.5%.The device realizes the precise application of medicine in the seedling belt under the straw collection mode,achieves the purpose of improving the utilization rate of liquid medicine and protecting the environment,provides methods and devices for the field of precise application of medicine,and provides technical support for promoting the promotion of conservation tillage.Secondly,the digital simulation software is used to optimize the wind curtain device.The gas-liquid two-phase flow is simulated by FLUENT software,and the flow field velocity and droplet trajectory are obtained.Then the relevant parameters are changed in turn to obtain the influence law of different factors on the wind curtain flow field.Through the analysis of the numerical simulation results of the gas-liquid two-phase flow field,it can be concluded that with the increase of the size of the air curtain outlet,the suppression effect of the air curtain on the droplet drift first increases and then decreases;When the horizontal distance between the air outlet of the wind curtain and the nozzle gradually increases,the inhibition effect of the wind curtain on the droplet drift first increases and then decreases;When the vertical distance between the air outlet of the wind curtain and the nozzle increases gradually,the inhibition effect of the wind curtain on the droplet drift decreases gradually;With the increase of auxiliary air flow angle,the suppression effect of wind curtain on droplet drift first increases and then decreases.Through the orthogonal test and variance analysis,it is concluded that the wind curtain device test platform is: the air curtain outlet diameter is 18.5mm,the horizontal distance between the wind curtain and the nozzle is 115.9mm,the vertical distance between the wind curtain and the nozzle is 80.0mm,and the auxiliary air flow angle is 25 degrees.Through the research and parameter optimization of the wind curtain type spray rod spray,it is shown that the optimized wind curtain type spray rod spray device can effectively reduce the amount of droplet drift and improve the uniformity of droplet settlement.