Improvement Design And Test Of The Self-taken Red Jujube Strip Gathering The Pickup Machine

In view of the single function of jujube harvesting machinery,only the functions of picking up and removing impurities can be realized.In the early stage of this project,a self-propelled jujube collecting machine was designed.The machine can complete the operation of landing jujube collecting and picking up,but there is still room for improvement in the prototype transmission system and main operating components,and the prototype operation effect needs to be further improved.In this paper,aiming at the shortcomings of the original prototype,the original prototype pickup device,transmission system and pipeline layout are improved and tested.Determine the prototype improvement scheme and design selection;the CFD-DEM coupling simulation method is used to design the pipeline layout.The response surface test was designed by Box-Benhnken method,and the optimal operating parameters of the prototype were optimized and verified.The main research contents and results are as follows :(1)Basic material parameter test of grey jujube.The long and short axis size,mass,volume,density,equivalent diameter and moisture content of jujube were measured.According to the physical parameter test,the accumulation angle of jujube,the rolling friction coefficient between jujube and soil,the elastic recovery coefficient of jujube and jujube,air duct and Q235 steel were measured.The measured material parameters can provide theoretical basis for simulation analysis and key device design calculation.(2)Optimization scheme and calculation selection.The performance test of the original prototype was carried out,and the improved optimization scheme was determined according to the test results.Select 4-68 centrifugal fan instead of the original pickup fan;the gas submerged jet theory was used to calculate and verify the airflow velocity at the nozzle required for the jujube collector.Calculate the maximum driving force and maximum power of the crawler chassis,and determine the main operating parameters and models of the drive motor;design the improved hydraulic and mechanical transmission system of the prototype,and determine the model of the main working parts.(3)The Fluent-EDEM coupling simulation was carried out to simulate the motion state of jujube material in the pipeline.According to the analysis of collision times,energy loss and particle erosion state of the bend,the orthogonal test was carried out with the erosion rate as the test index,and the optimal parameters of the pipeline were determined as the bend diameter of 130 mm,the bend Angle of 105° and the airflow velocity of 28m/s.And carry out the test to verify the pipeline optimization effect.(4)Single factor and response surface analysis test.According to the single factor test results,the test factors were determined to be forward speed,picking wind speed,unloading speed,and the test indexes were harvesting efficiency,leakage rate and damage rate.The mathematical model of each factor and test index was established.Verify the reliability of the optimal mathematical model,and use the best theoretical parameters to verify the test.The test results show that when the forward speed is 1.4km/h,the picking wind speed is 30m/s,and the unloading speed is 26r/min,the harvest efficiency is 716.91kg/h,the leakage rate is 8.89%,and the damage rate is 3.47%.The errors of actual value and theoretical optimization value of harvesting efficiency,leakage rate and breakage rate are 0.12%,1.99% and 2.25%,respectively.The mathematical model is reliable...