Font Size: a A A

Design And Experimental Research Of Automatic Control Weeding Device For Paddy Field

Posted on:2022-01-02Degree:MasterType:Thesis
Country:ChinaCandidate:X C MaFull Text:PDF
GTID:2493306311952379Subject:Agricultural mechanization project
Abstract/Summary:PDF Full Text Request
Rice is one of China’s main food crops,and its planting area ranks first among the three major food crops in China,which is of great significance to ensuring the country’s food production safety.Weeds in paddy fields severely restrict the yield and quality of rice.Therefore,efficient weeding methods are a crucial part of the growth period of rice.Mechanical weeding has been widely used as an effective weeding technical measure that has the advantages of avoiding chemical pollution,improving the physical environment of the soil,and promoting the growth and deve lopment of crops.The paddy field mechanical weeding device is the core of mechanical weeding,and its performance directly affects the quality and efficiency of weeding operations,which is of great significance for improving mechanized weeding.The existing mechanical weeding device is difficult to implement row and inter-plant weeding operations at one time,and due to the complex environment of the paddy field,low weeding rate,high seedling damage rate,and difficulty in guaranteeing operation quality.In response to the above problems,this article uses mechanical weeding technology as the basis,using theoretical analysis,mechanical structure design,automatic control technology,virtual simulation analysis and experimental research and other methods and means,combined with the actual field conditions of the paddy field,to carry out the research on the paddy field automatic control weeding device.Focus on breakthroughs in the design and research of core devices such as curved-tooth oblique inter-row weeding devices,arc-tooth automatic weeding devices between seedlings,etc.,and finally the integration and trial production of paddy field automatic control weeding devices.This experiment provides theoretical support and reference value for the in novative design of paddy field mechanical weeding devices.The main content and methods are as follows:(1)Design of curved-tooth oblique inter-row weeding deviceCombining theoretical analysis and mechanical structure design,in order to develop a weeding device that can efficiently and stably carry out weeding operations between rows,a curved-tooth oblique-mounted weeding device is designed.Through the mechanical analysis of the process of embedding the teeth into the soil and the excavation desorption during the operation of the weeding wheel,the corresponding mechanical model of the soil particles on the weeding wheel teeth is constructed,and the curved tooth structure is determined;according to the theoretical analysis combined with the agronomic requirements of weeding between rows,The main structural parameters of the weeding wheel and the value range of each parameter that affect the weeding performance are determined,and the value range of the radius of curvature ρ is 60~100mm,and the value range of the eccentricity e is 80~120mm.In order to improve the operation stability of the device,a single-hinge structure profiling mechanism was designed,and the main structural parameters of the profiling mechanism were determined.(2)Design of spiral-tooth automatic weeding device between seedlingsCombining theoretical analysis with mechanical structure design and automatic control technology,based on the idea of intermittent opening and closing movement of the weeding executive components and the design width of the inter-row weeding device in the early stage,a curved tooth for removing weeds between plants during paddy field cultivation is design ed.Type automatic weeding device to avoid seedlings.According to the growth status of rice plants d uring the weeding period and the design width of the inter-row device in the early stage,through theoretical analysis,we designed the opposite inter-plant weeding tooth,and determined the main structural parameters of the weeding arc teeth.The weeding operation areas are 0~30mm and25~60mm on both sides of the rice plant,and weeding between plants The total width is 120 mm.In order to avoid seedlings and weeding between plants,the photoelectric sensor and electric linear actuators are used to cooperate with each other to design an automatic control system for avoiding seedlings.When the device needs to perform the operation of avoiding seedlings and we eding,the system controls the weeding arc teeth to open a certain distance to avoid the seedlings.T he inter-plant device combined with the inter-row weeding device operation can reach 94.47% of the total weeding coverage.(3)Performance optimization experiment of weeding component-water-soil fluid-solid coupling virtual simulation based on LS-DYNAIn order to determine the best combination of structural parameters of the curved-tooth oblique inter-row weeding device and the best soil depth of the spiral-tooth type automatic seedling avoidance inter-row weeding device,the inter-row weeding device and the inter-row weeding device were established based on the LSDYNA explicit dynamics software.Device component-water-soil fluid-solid coupling model.The curvature radius and eccentricity of the inter-row device are selected as the test factors,and soil dis turbance rate and coupling stress are used as the test indicators.The orthogonal rotation test is used to carry out the multi-factor performance optimization test of the inter-row device;the soil depth is selected as the test factor for the inter-plant device.Taking the soil disturbance rate as the test index,a single-factor virtual simulation test of the inter-plant installation was carried out.The virtual simulation test results show that the optimal parameter combination of the weeding wheel between rows is the radius of curvature of 65.86 mm and the eccentricity of 113.27 mm,Soil disturbance rate and coupling stress were 88.21% and 0.04569 MPa in weeding zone between rows;the optimal depth of the weeding arc tooth between the rows is 32 mm.(4)Configuration design and field experiment of automatic control weeding device for paddy fieldBased on the previous research results,it is equipped with a curved tooth oblique inter-row weeding device and a curved tooth-type automatic seedling avoidance inter-row weeding device,and the other devices are selected,and the devices are integrated to complete inter-row weeding and inter-row weeding at one time.Weeding paddy field automatic control weeding device,and conducted field performance verification test of row,inter-plant weeding device and paddy field automatic control weeding device.Field test results show that the average weeding rate and average seedling damage rate of the inter-row weeding device are 89.66% and 2.10%,respectively.The operating performance is stable,and its comprehensive operation performance is better than that of the squirrel-cage type inter-row weeding device,which meets the agronomic requirements of the paddy field mechanical weeding operation.Technical requirements: The avera ge weeding rate of the inter-plant weeding device is 86.50%,the average seedling damage rate is 0.20%,and the performance of weeding and avoiding seedlings is stable,which can meet the agronomic requirements of paddy field weeding and the operation requ irements of "avoiding seedlings and weeding" between plants;automatic control of weeding in paddy fields The device has stable operation performance,the average weeding rate of the inter-plant weeding device is 91.67%,the average seedling damage rate is 2.87%,can complete row and inter-plant weeding at the same time,with high weeding rate,low seedling damage rate,and seedling avoidance and weeding betw een plants,meeting the requirements of paddy field weeding.
Keywords/Search Tags:Paddy field, mechanical weeding, curved-tooth oblique type, seedling avoidable weeding between plants, finite element method, experiment
PDF Full Text Request
Related items