Design And Experiment Study On The Spring-finger Type Of Peanut Pickup Device

Peanut is one of the most important oil and cash crop in China and the world. Although China produces huge amount of peanut crop, the level of harvest mechanization is relatively low, compared to developed countries. For most part of China, peanut is harvested manually. Peanut plants were digged and windrowed by diger, tied and picked up by hand after drying by sunshine in some areas. This way of peanut harvest costs a lot of time and labor, and the peanut on the field could turn bad due to rainy weather if it isn’t harvest in time. If picking method is not suitable, which is as primary process of peanut hearvest, made pods fallen off seriously. Foreign peanut harvest equipment is not very effective due to peanut types and planting ways in China. This paper combines with the specialized research fund for the doctoral program of higher education project "Study on Research on the dynamic damage mechanism of full-feed peanut picking and the low damage peanut picker" (project number:51575367) and "peanut picking combine core institutions working mechanism and key technology" (project number:20122103110009) and research the spring-finger pickup mechanism, which is the core part of sliding spring-finger cylinder pickup. In this article, analyzed the ideal position and swing ruls of the pickup component according to the typical peanut type and planting characteristics in northeast China. Also optimized the parameter of the mechanism and researched the prototype experiment.The main research contents and conclusion are as follows:(1) Experimental study on physical and mechanical characteristics of typical peanut plant. Including the tensile strength of the stem and key node on the peanut plant, the experiment to the different friction angles when the peanut plant responded to different material. So as to obtain the changing law of water percentage, the friction angle, the tensile strength of the stem and key node on the peanut plant with drying time.(2)Confirmed the pickup mechanism. Compared and analyzed different type of pickup mechanism, including sliding spring-finger cylinder type, retractable finger type, sliding elevator type, toothed belt type,non-sliding springer-finger type. Finally chosen the sliding spring-finger cylinder pickup mechanism as the pickup of two-stage peanut harvester, according to the analysis on structure, working principle and scope of application.(3)Pickup mechanism design and parameters optimization. Confirm spring-finger position and swing ruls in different step, according to the erect peanut plant character in our country. Cam slide centerline locus were designed by analyzing spring-finger swing characteristic, pickup parameters were optimized by using NSGA-Ⅱ based on C-language. After the analyzing the result, the main parameters of the spring-finger cylinder pickup machanism were confirmed.The crank length is 50mm, the angle of the spring-finger and the crank is 1.Orad, the flip angle of top shield is 0.3rad, the cylinder radium is 99.2mm, spring-finger length is 203mm, the picking flip angle is 0.3rad,the shield radium is 172.3mm.(4)Simulation and analysis on the pick machanism by using virtual prototype technology. Through kinematical and kinetic analysis of pick machanism by ADAMS, confirm that the leakage areas influence of pickup mechanism, the pickup should adapt four rows spring-fingers and further make sure the parameters were reasonable.(5)Fore analysis of pick machanism. The finite element analysis of spring-finger confirm reliabily. Limit condition of peanut plant avoid stacking, sliding, throwing and gripping was obtained by force analysis on peanut plant.(6)Experiment on spring-finger pick device. The optimal working parameters of spring-finger cylinder pickup were obtained by experiment with response surface method: forward speed was 48.0m/min, cylinder rotating speed was 53.1r/min, height above around was -7.4mm; The collecting rate and the loss rate were 98.9% and 2.5% respectively.Through observing and analysing the pickup experiments on 3 different peanut windrow ways(pods in front of peanut, pods in back of peanut, scattered plants), get conclusion that pods in front of peanut have the largest collecting rate.the lowest loss rate, the best continuity.