Research On Key Technology Of An Automatic Transplanter For Belt-shaped Cruciferous Vegetable Tray Seedlings Made Of Straw Fiber

At present,vegetable transplanting is mainly by manual and semi-automatic transplanter,but it exists low efficiency,high labor intensity and high labor cost,which limits the rapid and high-quality development of Chinese vegetable industry.In order to realize high-speed automatic transplanting operations,the idea of efficient planting with orderly separation and transportation of belt-shaped tray seedlings a new type of automatic transplanter is proposed,which is composed of disc-shaped seedling trays,an automatic leading out and separation device,planting device and control system.Aiming at efficient and orderly separation of beltshaped tray seedlings made of straw fiber,and an automatic leading out and separation conveyor device test platform was built through in-depth theoretical and experimental research on the key components of the transplanter and implemented parameter combinatorial optimization tests.The main research content and achievements are as follows:(1)Determination of physical and mechanical parameters of belt-shaped cruciferous vegetable tray seedlings made of straw fiber.Based on the production technology of beltshaped cruciferous vegetable seedling trays made of rice straw fiber.Using belt-shaped cruciferous vegetable tray seedlings made of straw fiber during the transplanting period as the test object,the physical and mechanical properties of tray seedlings such as moisture content,geometric parameter friction coefficient,compressive strength of tray seedlings,fracture resistance of joint and tensile force were measured.(2)General design of automatic transplanter for belt-shaped cruciferous vegetable tray seedlings made of straw fiber.Aiming at the efficient and orderly transplanting of cruciferous vegetable tray seedlings made of straw fiber,a new scheme of automatic transplanter was proposed.Through the kinematic analysis of the disc-shaped seedling tray,the rotation mode is determined to be passive,and the tray seedlings will not tear in the process of leading out;Based on the idea of efficient planting with orderly separation and transportation of belt-shaped tray seedlings,the design requirements of an Automatic leading out and separation conveyor device were put forward and the scheme of an automatic leading out and separation conveyor device for taking seedling at the cutting and connecting part was determined.Through the analysis and design of the Lead out mechanism and the planting mechanism,the key structural parameters and the range of working parameters are determined;Determine the range of sliding angle of the separation cutter,using MATLAB to optimize the parameters of the crank slider mechanism,analyzing the crank angle at the maximum speed of the cutter,as well as the length of the crank and connecting rod.(3)Design of PLC automatic control system.Design an automatic control system with PLC as the control core,including lead out speed control module,tray seedlings signal recognition module,separation mechanism reset module,control of lead out mechanism,separation mechanism coordination movement.To explore the impact of extraction speed on the performance of the control system,a single factor experiment was conducted using extraction speed as the experimental factor,The test results show that the lead out speed has a very significant influence on the relative error of the separation position,and the relative error of the separation position can meet the performance requirements of the separation position control system.(4)Experimental study on parameter combination optimization of an automatic leading out and separation conveyor device.By bench test,the feasibility of orderly separation and transportation of belt-shaped tray seedlings is Verified.The whole operation process of tray seedlings from lead out to separation was analyzed,and the main factors affecting the separation of belt-shaped tray seedlings made of straw fiber were found.Using three factors and five levels quadratic regression orthogonal rotating center combination test method,the bench test was carried out with the lead out speed,blade sliding angle and crank speed as the test factors,and the tray seedlings separation rate and pot body damage rate as the evaluation indexes.The results showed that all factors had significant effects on the separation rate of tray seedlings,and the order of effects were lead out speed,blade sliding angle and crank speed;All the factors have very significant effects on the failure rate of the pot,and the order of effects is lead out speed,crank speed and blade sliding angle.The optimized parameter combination ranges were: lead out speed 96 mm/s-156 mm/s,blade sliding Angle 44°,crank speed 3.3 r/s-4.1 r/s,tray seedlings separation rate ≥94% and pot body damage rate ≤4%.The verification tests were carried out with this parameter combination,the separation rate of tray seedlings was above 94%,and the damage rate of pot was less than 4%,the results of the study have laid the foundation for the development of an automatic transplanter for belt-shaped cruciferous vegetable tray seedlings made of straw fiber.