Design Of Orchard Air-assisted Sprayer Control System Based On Multi Sensor Fusion

In view of the waste of liquid spray produced by continuous spraying and spray leakage caused by spray drift in most orchards in our orchard,the wind drift model based on spray speed and spray distance was fitted based on the CFD(Computational Fluid Ddynamics)technology developed by the previous developed wind sprayer.Based on the fitting wind drift model and the optimized positioning model,a control system based on multi-sensor fusion is developed,which can effectively restrain the spray drift of the sprayer,achieve precise target spraying,reduce the waste of liquid and environmental pollution.The main research contents and conclusions are as follows(1)research on the drift model of sprayer based on CFD technology.The FLUENT component transport model is used to simulate the dynamic drift field of the wind driven sprayer with the effective drift field of the percentage of water content.The relationship between the drift distance of the sprayer and different walking speeds and different spray distances is studied,and the drift field model of the sprayer is obtained,which provides a theoretical basis for the dynamic control of precision spraying.(2)Location model optimization based on multi-sensor fusion.According to the optimization conditions of positioning model considering accuracy and economic applicability,information fusion between laser sensor and depth camera is used to estimate the trend of the sprayer and the middle point of the fruit tree crown.The information of the laser sensor and the ultrasonic sensor is used to fuse the information of the sensor and the ultrasonic sensor to determine the location relationship between the crown and the crown of the fruit tree.Realizing the function of early detection and determining the starting time and ending time of the spray operation,the optimization of the positioning model of the control system is completed.(3)design of control system based on wind driven sprayer.Based on the flow field drift model and the positioning model,the control strategy for the design of the wind driven sprayer is to deduce the drift distance in the horizontal direction and control the spraying height range in the vertical direction.The corresponding control system is built according to the control strategy.It can be realized: the horizontal target is realized by the delayed spray based on the drift model,and the fruit tree is recognized in real time to adjust the spray angle based on the height of the tree crown to achieve the vertical target.(4)the simulation validation and control system performance test based on the spray control simulation platform.In order to verify the accuracy of the component transmission model,a spray control simulation platform was built,and the simulation validation test was designed for it.The results show that the simulation based on component transmission model is basically effective,and the simulation results of wind drift can reflect the real spray situation to a large extent.The performance test of the control system was designed.The performance of the control system was judged by the spray cover rate of the water sensitive paper before and after installing the control system.The test results showed that after the opening control system,the spray droplet coverage rate near the top of the spray machine was close to 90%,which was significantly improved compared with that without opening.The performance of the control system based on multi-sensor fusion is better than that based on single ultrasonic sensor.