| Fruit and vegetable quality detection and grading based on machine vision has beenwidely applied in practical production in foreign countries, and that has brought hugeeconomic benefits to the fruit industry. However, the high price and maintenance costs makethem hard to be applied interiorly. Chinese scholars have been focusd on large fruit sortingtechnology, such as apple and so on, but seldom involves in that of little fruit, especially injujube. In this paper, several key components of the jujube automatic grading equipment arestudyed on the basis of foreign research results. The main subjects and conclusions of theresearch were as follows：(1) Overall design of the the jujube automatic sorting machine was carried outaccording to its working principal, including productivity and other parameters, feedingapparatus, transportation methods and discharging device. The corresponding design sketchwas obtained.(2) In the case of this subject, design requirements as well as the considerations ofconveying system is given; under which the structural design is carried out. Speed and forceanalysis of the jujube is carried out in the given model, based on which, the relationshipbetween the size of jujube and absolute error of rotation angle of that is discussed.(3) The effect of phase difference as well as driven sprocket support spring on the speedunevenness coefficient were studyed in the virtual prototype model of the secondary chaindrive. The result that speed unevenness coefficient reached the lowest and is74.42%less thanthe initial model with the phase difference at-10.714°was found. In the virtual prototype ofone stage chain transmission with extended supporting spring of driven sprocket speedunevenness coefficient is52.32%lower than the initial model when the preload force is4800N and the stiffness coefficient at20N/mm. The conclusion of that the former method ismore effective according to data comparison. The bonding mechanism of these two methodsneeds more further exploration.(4) The author designed a conveying apparatus which can be installed on the conveyingchain without additional components. The model of jujube and distributing apparatus virtualprototype was established by using the dynamic simulation software—ADAMS. The lengthof off-loading cam and position of virtual sensor in this virtual prototype were determinedthrough virtual single-factor tests,which proved the reliability of the model. The falling trace spline of jujube weighing8g to35g were obtained. The results showed that the model canachieve the best effect when the magnification times of off-loading cam is4and the initialdistance between the bracket and the sensor is50.8mm, with the culmination being100mmand the horizon distance being60mm respectively. Jujube weighing8g to35g could bedistributed successfully and the model could also unload3jujubes one by one. Test resultsshowed that discharging apparatus designed in this paper can be successfully applied toautomatic grading machine that could handle5jujubes per second. |
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