Research On Vibration Characteristics Of Sapindus Tree And A Harvesting Rod Of The Fruit

As a forestry biomass energy,Sapindus has great economic value.The main component of the Sapindus rind is natural detergents,which can be used as a surfactant,and Sapindus have also been proven to have medicinal effects and can be used for deworming,anti-inflammatory,antitussive,and so on.The oil content of the seedless seed is as high as 42.7%,which is a new raw material for biodiesel.However,artificial picking is also used on the picking of the fruit.This leads to inefficiency,time and effort,and economic benefits.Therefore,it is necessary to design a vibration harvesting machine for the vibration characteristics of the tree.The main research content of this paper is:(1)The vibration motor—the mathematical model of the vibration of the Sapindus tree was established,and the vibration form of the fruit tree with the external excitation was analyzed.It was concluded that the fruit tree would vibrate as the vibration source.By further simplification,the frequency and acceleration were approximated the relationship of the quadratic curve.The modal analysis and vibration response test of the fruit trees were carried out to study the vibration response characteristics of the fruit trees under different excitation conditions.According to the image of the collected acceleration value,the fitting curve found that the frequency and the acceleration were approximate a quadratic curve relationship,which was consistent with the mathematical model conclusion.The modal analysis shown that the natural frequency of the fruit tree was different due to the structural difference.The vibration response of the fruit tree increased with the increase of frequency,while the excitation position with high vibration was good at low frequency,and the excitation position was low at high frequency.For fruit tree branches,the absorption of vibration energy by the coarser branches was always larger than that of the twigs,and it was more obvious at higher frequencies.(2)According to the obtained vibration parameters,the vibration recovery test was carried out in the harvest season.Changing the number of exciters,the double excitation recovery was better than the single excitation,and the acceleration root mean square(RMS)of the double excitation was two to three times that of the single excitation compared to the single excitation acceleration RMS.And the picking rate of the double excitation was 92.3%at 20 Hz.In addition,as the frequency increases,there were four different locations of the harvested fruit.The breaking location at the ear and the fruit stem is the most important forms.Their microstructure was observed by microscopy and it was found that the fruit and fruit steims had thinner and cleaner cell walls and cell cavities.This microstructure may be the reason why it was easier to fall off.(3)A portable Sapindus vibration picking rod was designed by calculating the exciting force in the test.Different picking claws of the vibration+picking mode were designed and the picking test was carried out during the harvesting season.It was found that the harvesting effect of the nine-claw vibrating picking rod was the best and it was above 85%,the picking rate after passing through the vibrating+raking was closed to 100%.In order to reduce the vibration and fatigue of the opponent when the harvesting rod was working,the human-type bracket auxiliary device was designed to buffer.Comparing the vibration value of the hand-carrying vibration with or without the buffer frame,the experimental results shown that the human-type bracket auxiliary device could reduce the weighted acceleration of the harvesting rod from the range of 4.26?7.24 m/s2 to 0.53?0.90 m/s2,which could both mitigate the vibration and reduce the vibration so that making the harvesting work better.