Research On Characteristics Of Potato Harvester Vibration And Potato-Soil Separation Based On Chaos

Potato is the world’s fourth largest food crop after rice,wheat and corn.China has a long history of potato cultivation,production and planting areas ranked among the world’s top.At present,most small potato harvesters vibrate linearly through a crank-link mechanism,with a single vibration frequency,resulting in poor soil and potato separation.In this paper,chaotic vibration is applied to the potato harvester,and when the parameters meet certain conditions,the wide frequency vibration response is output by inputting a determined excitation,so that the vibration has a more drastic speed change,thus improving the probability of collision between the materials and the vibrating screen and between the materials and the materials,avoiding the blockage of the sieve bar gap,strengthening the flow of the material,and improving the soil-potato separation rate in the potato harvesting process.The specific research is as follows.Firstly,the current research status of potato harvesters at home and abroad is introduced,and the problems of small potato harvesters are analyzed;the basic concepts of chaos theory and chaos identification methods are introduced;the mathematical model and three-dimensional model of the chaotic shaker with three eccentric wheels are established,the simulation parameters are determined,and the identification of chaotic features of the shaker is completed by numerical simulation.Secondly,the specific parameters of the vibrating screen are determined by establishing the three-dimensional model of the whole machine,The motion parameters are verified to meet the harvesting requirements of the potato harvester;the vibration response of the vibrating screen at different motor speeds is identified as chaotic;then the modal analysis and harmonic response analysis of the vibrating screen are performed and the structure of the vibrating screen is optimized to meet the working conditions;in order to further verify that the vibrating screen has chaotic characteristics,a bench test is set up to collect acceleration data and verify the chaotic characteristics through the chaotic identification method.Finally,by the discrete element method,the soil and potato discrete element models were established and coupled with the discrete element software EDEM and the automatic dynamics analysis of mechanical systems software ADAMS for simulation.The motor speed and the inclination angle of the vibrating screen are used as factors,and the return displacement of potato,the maximum value of the force suffered,the soil penetration rate and the penetration efficiency are used as indexes for simulation.The results show that the motor speed 330r/min and the vibrating screens inclination angle 8.2°,the motor speed 360r/min and the vibrating screens inclination angle 8.2°,can take into account the potato transport and soil separation,And this parameter is used as the optimal parameter for the chaotic vibrating screen of potato harvester designed in this paper;Comparing with the soil penetration of conventional vibrating screen under the same parameters,it is verified that chaotic vibrating screen has better penetration effect on soil;The optimal parameters in the simulation results were used as conditions for potato conveying tests to analyze the skin breakdown rate and conveying rate of potato.