Design And Experiment Of Bag-in-bag Packaging Device For Table Grapes

Fresh grapes are a kind of berry fruit that grows in clusters and is loved by people because of its juiciness and vitamin-rich content.With the development of agricultural picking mechanization and intelligence,the mechanical arm is the trend of fresh grape harvesting instead of manual.Due to the thin and juicy skin and high water content of fresh grapes,the lack of effective protection during harvesting,packaging and transportation can cause damage such as wear,collision and threshing.Therefore,there is an urgent need to design a collection device for joint robotic arm collaborative harvesting,which can be collected immediately after picking to avoid damage.Aiming at the characteristics of grape clusters with irregular shape,thin and juicy skin growth and the agronomic requirements of non-destructive harvesting,the bag-in-bag packaging device of the integrated machine for non-destructive harvesting of fresh grapes was designed to cooperate with the grape picking robotic arm to complete the nondestructive harvesting of fresh grapes,and the main research contents are as follows.（1）Mechanical structure design of the bag-in-bag packaging device for fresh grapes.The bag-in-bag packaging device for non-destructive harvesting of fresh grapes was designed according to the vertical hanging growth characteristics,biological characteristics and agronomic requirements of non-destructive harvesting.The three-dimensional structure of the bag-in-bag packaging device is designed using SOLIDWORKS,which mainly includes the bag storage box,bag pickup mechanism,bag propping mechanism and inflation mechanism,and illustrates the working process of the non-destructive all-in-one machine for fresh grape harvesting.（2）Design of key parameters of the bag-in-bag packaging device for fresh grapes.For the problem that there is no uniform air pressure standard for the bag-in-bag after manual inflation,resulting in uneven protection effect,the key components of the bag-in-bag packaging device are designed.Firstly,based on Shimadzu EZ-Test EZ-SX texture analyzer squeezing single grape test,combined with the analysis of maximum contact force and minimum contact force of squeezing rupture of bag-in-bag,the minimum squeezing rupture force of 16.25 N and maximum inflation air pressure of 24.8k Pa were determined;then,through the drop protection test of packaged grapes,according to the surface Then,through the post-packaging drop protection test,based on the measurement results of four indexes: surface rupture index,surface hardness,mass loss rate and puncture rupture force,it was determined that the best protection effect was achieved when the bag-in-bag inflation air pressure was 4k Pa;then,the bag-in-bag packaging device was analyzed for the force of the bag-in-bag bag propping process,and the minimum suction force and diameter provided by the suction cup were determined to be 6.125 N and 30 mm.Finally,by experimentally measuring the number of grape pixels,volume and inflation time,the pixel point-inflation time relationship was fitted and the inflation time was calculated to ensure the best protection effect for each bunch of grapes after packing.（3）Fresh grape bag-in-bag prototype performance test.In order to verify the performance of the prototype,first,the control system hardware of the bag-in-bag packaging device for fresh grapes was selected and designed;then,the timing control,motor motion control and inflation time control programs of the device were written using Keil u Vsion5 software;finally,the prototype bag-in-bag packaging device was processed,and the prototype and manual packaging comparison test was designed.The test results show that the fresh grapes bag-in-bag packaging device has a 95% nondestructive packaging success rate,an average packaging time of 28.4s,a maximum atmospheric pressure deviation of 0.2k Pa,an average air pressure deviation rate of1.125%,an average rupture rate of 1.5%,an average threshing rate of 0.2%,and the ability to package 126 bunches per hour.The bag-in-bag collection device has stable operational performance and high success rate of non-destructive collection of fresh grapes,which effectively solves the problems of timely packaging and efficient collection of fresh grapes after harvesting,avoids damage,ensures freshness,and improves picking and collection efficiency,and can provide reference for the development and optimization of subsequent fresh grapes non-destructive harvesting integrated machine.