Design And Experimental Research On Spiral Comb Type Apple Harvester

The scientific integration of agricultural machinery technology and agronomic technology is the common direction of the reform of orchard cultivation mode and the research and development of orchard operation equipment.In view of the urgent need for mechanized harvesting in apple production and the difficulty that existing mechanized apple harvesting equipment is difficult to apply in orchards,this study starts from two aspects: the adaptive transformation of apple trees and cultivation models and the method of mechanized apple harvesting.Through the scientific integration of apple cultivation agronomic techniques and apple mechanized harvesting methods,the "丰"-shaped apple tree structure suitable for mechanized harvesting and the wall-shaped cultivation mode of "fruit branches parallel to the fruit rows" were proposed.A kind of apple batch harvester that is matched with it and can continuously complete apple picking,conveying and collecting operations during the walking process—spiral comb-type apple harvester,and relevant harvesting tests have been carried out.The main contents and The research conclusions are as follows:(1)Overall Design of Spiral Comb Type Apple Harvester.According to the technical idea of scientifically integrating apple cultivation agronomy and apple mechanized harvesting methods to develop harvesting equipment,the existing bead curtain-shaped apple tree branch distribution structure was adapted to mechanical harvesting,and the "丰"-shaped apple tree structure was proposed.And the wall-shaped cultivation mode of "fruit branches parallel to the fruit rows" has completed the working principle design of the spiral comb-type apple harvester that is matched with it and can continuously complete apple picking,conveying and collecting operations during the walking process.,to determine the overall layout of the machine structure.(2)Design and Analysis of Spiral Comb Type Apple Picking DeviceUsing the dynamic principle and numerical calculation method,the dynamic model of the branch-stalk-fruit system was constructed,and the force and motion state of the apple during the picking and separating process were analyzed.The separation principle of the branches and the four factors that affect the separation process: the rotation speed of the spiral brush,the pitch,the traveling speed of the whole machine,the contact position of the spiral brush rod and the apple;the structural parameters of the spiral brush rod are determined.Based on Abaqus 2018 software,the finite element model of branch-stalk-fruit was established,and Cohesive Sufaces was used to simulate and analyze the binding force of fruitstalk-twig.The relative error is 3.45%,which proves that it can describe the separation process of fruit stem and branch more accurately.The finite element model was used to simulate and analyze the separation movement of branches and stalks and the damage of apples under the action of the helical brush.The relative errors are 11.5% and 10.11%,respectively,which proves that the finite element model can more accurately describe the separation process of fruit stem and branch and the damage of apple under the action of spiral comb.Based on the finite element model,a Plackett-Burman simulation test was designed and carried out.The test results show that the significant parameters affecting the separation process of apple stalk and branches under the action of the spiral brush are the speed of the spiral brush,the pitch,and the forward speed of the whole machine.(3)Design of post-harvest collection and conveying device for spiral comb type apple harvesterIn order to ensure that the apple collecting plate can receive postharvest apples effectively and low-loss,the maximum stress on apples is used as the response index,and a finite element simulation test is carried out on the process of apples falling to the apple collecting plate.The test and optimization results show that: When the traveling speed of the harvester is 150 mm/s,the material of the apple collection plate is EPE pearl cotton,and the inclination angle is 12.36°,the damage rate of the apple collection plate to the postharvest apples is the smallest.In order to ensure that the collected apples can be transported to the fruit collection bucket with high efficiency and low loss,the apple damage rate and the collection rate are used as response indicators.The optimal conveying speed is 180mm/s.(4)Drive and Control System DesignTaking the STM32L031G6U6 processor as the core,a set of control and control system for the operation parameters of the whole machine has been developed.At the same time,the telescopic and lifting of the picking platform,the rotation speed and reversal of the spiral brush rod,and the forward speed of the whole machine are remotely controlled.(5)Trial production and orchard harvesting experiment of spiral comb type apple harvesterThe first-generation prototype of the helical comb-type apple harvester was trialproduced,and the harvesting simulation experiment was carried out in the orchard with the apple recovery rate and damage rate as the response indicators.The test and optimization results show that the spiral comb-type apple harvester can continuously complete apple picking,conveying and collection during the walking process,and the forward speed of the whole machine is 159 mm/s,the screw pitch of the spiral combing rod is 110 mm,and the spiral When the brush rod rotation speed is 1.05 r/s,the recovery rate is the largest and the damage rate is the smallest,which meets the design requirements.