The Development Of An Automatic Orchard Spraying Machine In Hilly And Mountainous Region

In recent years,along with the economy fast development,people's living standard raises gradually,at the same time,the demand for fruits also increases a lot.The orchard pest control,as an important section in orchard management,has an effect in the production.Traditional method uses large amounts of pesticides,which causes excessive pesticide and wastes liquid,resulting in great pollution on the surrounding environment.In the southwest of China,most regions are hilly mountains and large machine cannot work in the orchard.In order to spray pesticide automatic,improving the utilization rate of pesticide and reducing the pollution to the environment,this paper develops an automatic spray pesticide machine.The machine includes four ultrasonic sensors used for identifying the location of fruit trees,two slides used for adjusting the height and distance of nozzle,rotating mechanism used for automatically adjusting the direction of spray nozzle which could increase the spraying rate.System can real-time control nozzle open and close,improving the effect of pesticide spraying and reducing the loss of pesticide.The paper can be summarized as below:(1)After reading literatures about automatic spray technology widely,we can determine the spray scheme of the control system of self-propelled sprayer.The spray control scheme is divided into two categories: manual control and automatic control.According to the distance of the fruit tree detected by the ultrasonic sensors,the automatic control system can recognize the objective and control the moving organization to adjust the orientation of the nozzle.The adjusted nozzle can spray the pesticide toward target precisely.Manual control system mainly controls the moving mechanism and nozzle by pressing the keys.(2)Designing moving mechanism,detection mechanism and control system according to the demand of the spray machine.The moving mechanism including two slides and stepper motors connected with a sprayer is used for adjusting posture of the nozzle.We choose KS-109 small beam angle of the ultrasonic sensors to detect the objective which is made by the Shenzhen electromechanical guidance technology co.,LTD.The control system including data collection modules,manual control module,automatic control module and motor control module is designed based on STM32F103.The real-time communication between the various modules is realized by using CAN bus.(3)Establishing hardware circuit design and software programming about each of the modules in the control system.The whole system can realize the function of the automatic control and manual control of the nozzle.(4)Testing the performance of ultrasonic sensor positioning accuracy,beam angle and crosstalk testing.According to the speed of the spraying machine and property about ultrasonic sensors,the layout of the four ultrasonic sensors can be drawn out which can realize the accurately target.According to different distance between canopies,the corresponding target mode can be chosen with the machine's speed 0.5m/s.(5)The original prototype machine is experimented outside and optimized.The modes of the automatic target detection are divided into two modes: automatic mode 1(spray lance can't rotate)and automatic mode 2(spray lance can rotate).After the optimization,the proposed machine is experimented again.As it shown in the measured results,the detecting system cannot distinguish the canopy gap when the gap between the two trees is less than 0.25 m and the speed is 0.5m/s.However,the proposed system can distinguish the gap efficiently when the distance of two trees are larger than 0.25 m.When the canopy gap is between 0.25 m and 1m,the automatic target is spraying under the mode 1 and control the nozzle in real-time in order to reduce the use of pesticides,and the amount can be reduced of 14.2% compared with continuous spraying.When the distance is beyond 1m,the mode of the automatic target can be chosen freely.The mode1 can reduce the amount of pesticides of 34.3%.The mode2 can control the rotation of the spraying bar to make the pesticide coverage more balanced.In addition,the mode 2 can also control the nozzle in real-time to increase the crown side coverage from 10% to 20%.Compared with continuously spraying,the mode 2 can reduce the whole spraying amount of pesticides by 8.8%.(6)Considering the characteristics of hilly mountain,we design a manual operation system for those areas that the caterpillar vehicle cannot reach.