Research Of Conveying And Packing System On Orchard Picking Platform

China is the world's largest producer of apples,and the apple industry has played an important role in developing regional economies and increasing farmers' incomes.In order to achieve the modernization of orchard,agronomist has put forward the planting mode of "wide row,short anvil and dense planting" after years of research and production practice.Due to the complexity and high cost of picking robot,it is difficult to be widely used in a short time.Therefore,the semi-automatic orchard picking platform will get preferential development.The core part of the orchard picking platform is the conveying and packing system,which is to collect,transmit and pack the apples that have been artificially picked.However,rolling,falling and collision usually cause some damage to apple and affect the quality of fruit in the process of mechanical picking.Aiming at the above problems,the paper designs a system of conveying and packing with the orchard picking platform,and carries out the prototype test.The main research contents and conclusions are as follows:(1)Based on the planting mode of " wide row,short anvil and dense planting",combining apples' mechanical damage mechanism,the overall scheme of the conveying and packing system of orchard picking platform was determined.Among them,the width of the conveying belt is 800 mm and the length of conveying belt is 3000 mm.The system is driven by a speedregulating motor to drive the conveyor belt and automatically completes the conveying and packing process of the apples.The swing of the moving conveying device causes the apples to land evenly on the bottom of the box.The fruit box is placed on the spring frame and its vertical displacement is linearly related to the weight of the apples in the box.(2)Based on EDEM,the packing process of the conveying and packing system in the orchard picking platform was simulated in order to verify the rationality of the design scheme and the range of working parameters for system.Established apple modal and apple box model,then simulated apple-packing process in the different value of swing frequency,swing amplitude and conveying efficiency,then compared the surface accumulation shape and apples' damage rate.The simulation results showed that when the swing amplitude of swing conveying device was 800 ~ 850 mm,apples could basically stack layer by layer in the packing process;however,when the swing frequency was from 1/25 Hz to 1/5 Hz,the conveying efficiency was from 2 to 6 apples per second,these two parameters had little influence on the surface shape of the apples stacking.When the swing amplitude was 800 mm,swing frequency was than 1/10 Hz,the conveying efficiency was 3 apples per second,the packing quality of apples was the best,the apple damage rate was within 5%.(3)Designed the key parts of the prototype and completed the virtual prototype assembly.The designing and parameter calculation of the fork frame,portal frame,chute,transmission shaft,spring and other key parts in the packing frame were completed.ANSYS was used for the static analysis of the fork frame and the transmission shaft,the maximum stresses for the fork frame and the transmission shaft were 91.255 MPa and 136.12 MPa respectively,t he maximum deformation of the fork frame and the transmission shaft were 7.19 mm and 0.76 mm respectively,the structural strength met the actual working demand.The overall structure of the conveying system(including conveying frame,conveyor belt and cylinder,etc.)and the swing control system of the moving conveying device were designed;all parts' three dimensional model and prototype assembly were completed through CATIA software.(4)Completed the prototype performance test.Spring frame performance test show that,after loading weight for fork frame,the error between the theoretical descending distance and the actual descending distance was small.The test results of conveying and packing test showed that the system could finish the conveying and packing procedure and reduce effectively the collision damage in the process of apple conveying and packing by the swing of moving conveying device and the spring control of box frame,the packing quality of apples met the design requirements.The orthogonal test results showed that the optimal combination of the system working parameters was: the swing frequency of the moving conveying device was 0.1 Hz,the transmission efficiency was 3 apples per second,and the linear speed of the conveying belt was 0.1m/s.In this condition,the operating efficiency of the system was 10800 apples per hour.