Design And Experiment Of Conveying And Packing Device For Apple Picking Robot

China ’s apple production ranks first in the world,and the apple industry is crucial to the development of regional economy.Fresh apples taste sweet and nutritious,loved by people.At present,fresh fruit harvesting is mainly completed by manpower,with high labor intensity and high labor cost.As a flexible intelligent agricultural machinery and equipment,agricultural robots have attracted more and more attention from researchers.Agricultural robots are easy to cause damage to apples when harvesting apples,especially in the transportation and packing of postharvest apples.In this paper,aiming at the problems of poor uniformity and high damage rate of apple postharvest conveying and packing,a double-layer uniformly distributed blade apple conveying and packing device is designed.The basic structure and working principle are expounded,and the prototype of apple conveying and packing device is developed and tested.The main research contents are as follows :(1)Red Fuji apple was selected as the test object,and its basic physical characteristic parameters were measured through experiments.The impact process of apple falling to buffer material was theoretically analyzed.The collision damage law of apple falling to buffer material was studied by orthogonal test.The influence of falling height,collision material type and collision material thickness on apple damage volume was analyzed.Through apple compression test and free falling test,the critical falling height of collision damage of apple falling to 3mm thick pearl cotton material was 71.34 mm,which provided a basis for the structural design of apple postharvest conveying and packing device.(2)The design scheme of apple picking robot conveying and packing device is introduced.The discrete element simulation platform of EDEM and Recurdyn coupling is built to simulate the packing process of apple in the conveying and packing device.When the rotation speed of uniform mechanism,the height of uniform mechanism and the inclination angle of uniform blade are different,the stacking shape of apple packing surface and the damage rate of apple are compared.The simulation results show that the rotation speed of the uniform mechanism has a significant effect on the stacking shape of the apple packing surface.When the rotation speed of the uniform mechanism is 10 ～15 r / min,the apple can be packed layer by layer.When the height of the uniform distribution mechanism is 110 ～ 120 mm,the shape of the packing surface is basically flat.When the inclination angle of the uniform blade is 8 ～ 12 °,the influence on the shape of the packing surface is not obvious.When the rotation speed of the uniform mechanism was 15 r / min,the apple damage rate was 3.33 %.When the height of the uniform mechanism is 110 mm,the apple damage rate is 5 %;when the uniform blade inclination angle is 10 °,the apple damage rate is 4.17 %.Therefore,the structural design scheme is reasonable,and the damage rate of apple can be controlled within 5 %.(3)The collision buffer model of apple falling into the buffer pipeline is established,the motion analysis of the moving apple in the pipeline is carried out,and the buffer pipeline is designed.When the height difference between the two ends of the pipeline is greater than 28.5 cm,the apple can just roll out smoothly from the pipeline.The uniform distribution separation component of the windmill packing and storage mechanism is designed in detail.In order to realize the automatic conveying and packing of apple,the control system is designed,and the hardware selection and packing workflow design are completed.(4)The prototype of the apple picking robot conveying and packing device was built and the performance test was carried out.Through the design and analysis of the device and the results of the previous simulation test,the rotation speed of the uniform mechanism,the height of the uniform mechanism and the inclination angle of the uniform blade were selected as the influencing factors,and the single factor test was carried out.On the basis of single factor test,according to the Box-Behnken test design method,a three-factor and three-level analysis test was designed.The rotational speed of the uniform distribution mechanism was selected as 10 r / min,12 r / min and 14 r /min.The height of the uniform distribution mechanism was 100 mm,110mm and120 mm,and the inclination angle of the uniform distribution blade was 4 °,6 ° and 8 °.The influence of each test factor on the packing effect and packing quality of the apple conveying and storage device prototype was analyzed.The test results were optimized by Design-Expert 11 software.The optimization results showed that when the rotation speed of the uniform mechanism was 12 r / min,the height of the uniform mechanism was 107 mm,and the inclination angle of the uniform blade was 6 °,the uniform coefficient of apple packing was 0.294,and the damage rate of apple packing was4.21 %.The optimized parameters were tested.The uniform distribution coefficient of apple packing was 0.288,and the damage rate of apple packing was 4.26 %,which met the requirements of apple packing operation.