Research On Orchard Target Variable Spray System Based On Kinect

Spraying is the main way to control diseases and insect pests in orchards.Traditional operation methods often cause problems such as low utilization rate of pesticides and excessive pesticide residues in soil,which not only pollute the environment,but also threaten the life and safety of farmers.In order to effectively reduce the use of pesticides and improve the utilization rate of liquid medicine,the variable spray control system of tracked orchard based on Kinect sensor is studied in this paper.The system organically combines the target spray with the variable spray,and implements the target variable spray according to the presence of the target and the size of the target area.The main research contents are as follows:(1)This paper analyzes the advantages of the target variable spray technology,puts forward the design tasks and requirements of the control system,designs the overall scheme and the structural diagram of the control system,and designs a crawler orchard variable spray control system to overcome the problem of complex orchards and difficult operation in the orchard.In order to improve the working efficiency of the system,the single-chip microcomputer STM32F407VET6 is selected as the CPU of the system,the spray pressure is adjusted by controlling the servo motor,the spray flow is adjusted by controlling the opening and closing time ratio of the solenoid valve,and combined with the identification and processing technology of the Kinect sensor to control the spray output in real time.(2)In order to obtain the information of pesticide application target,the leaf wall(LWA)region detection method which combines the target color and depth image information is adopted,which can effectively detect the presence and size of the target.In order to improve the pesticide utilization rate,the detection method of LWA region density is used to study the distribution of LWA region density of different fruit trees to meet the requirements of target variable spraying operation for different orchard types.On this basis,through the water sensitivity test paper test,it is verified that the variable spraying method based on LWA region meets the requirements of orchard pest control.(3)In order to obtain the best spraying distance of the sprayer,combined with the target depth information collected by the Kinect sensor,the detection method of the average distance in the LWA area is adopted,and then the optimal spraying distance is determined according to the width of the spraying equipment and the spraying range of the nozzle.In order to solve the problem that the sprayer deviates from the optimal spray distance,the calculation methods of path deviation and path correction are adopted,and the peach forest is taken as an example to correct the sprayer deviation path,so that it is always on the best spraying path to achieve accurate target variable spray.(4)In order to improve the liquid utilization rate during spray operation,a dynamic PWM variable spray test platform is designed to analyze the droplet distribution uniformity.In the experiment,carmine solution is used instead of medicine solution,concentration-absorbance technique and response surface method are used to draw the response surface diagram of the influence of PWM duty cycle,PWM frequency and spray advance speed on droplet distribution uniformity by Design-Expert.The experimental results show that all three have significant effects on the droplet distribution uniformity,and the PWM frequency has the greatest influence;the PWM duty cycle and PWM frequency play a positive role in improving the spray distribution uniformity,while increasing the spray forward speed can not improve the spray distribution uniformity;when the droplet distribution uniformity is the best,the corresponding coefficient of variation(CV)is 1.17%.