Study On The Mechanism Of Fruit Tree Vibration Harvesting

The planting area and the increasing yield of forest fruits have brought new challenges to the harvesting work.There is no denying that mechanized forest harvesting is gradually replacing the traditional artificial harvesting.In recent years,with the continuous advancement of research,the research on the mechanized harvesting of walnut,jujube,olive,apricot,cherry and citrus has made great progress.Machine in the process of collecting,however,for the vibration parameters（e.g.fruit trees vibration position,working frequency of the vibration and vibration duration and vibration amplitude.etc.）are often the lack of a reasonable choice.This makes fruit picking efficiency is not high,in the process of collecting will also because of improper excitation parameters setting broken fruit trees,tree bark and leaves fall off,this is very serious damage in fruit trees,fruit trees even killed,seriously affect the fruit production next year.In view of this situation,the following research has been done:Firstly,the indoor impact test of fruit trees was carried out.The logarithmic attenuation method was used to calculate the ratio range of fruit tree branches to 2.78%⁴.97%.By means of frequency-domain analysis,it is concluded that the branches of fruit trees resonate at about10Hz and 25Hz,and it is concluded that the resonant peaks generated by the branches in 25Hz are larger.It can be concluded that in order to improve the harvesting efficiency of the fruit,the excitation frequency of the exciter should be selected at about 25Hz in the process of mechanized harvesting.Secondly,the indoor continuous vibration test of fruit trees was carried out.The measured acceleration signal curve fitting,the fruit trees under sine excitation load,the acceleration signal of fruit tree branches approximate sine function changes,and the external excitation load frequency and the acceleration signal is almost unanimously,trunk will also further illustrates the fruit tree branches of each measuring point of the acceleration signal as a sine function is correct.By calculating the fruit tree branches different measuring point relative to the value of the kinetic energy than that can be used to compare the energy transfer efficiency and the fruit tree branches related to its diameter,branch diameter,the greater the energy transfer efficiency is higher,the energy transfer efficiency is higher than on fruit tree trunk on the lateral branch transfer efficiency.It is also concluded that when the bifurcation Angle of the two branches is approximately equal,the energy will flow more to the side with a larger diameter.Finally,outdoor high speed camera to luntai county,xinjiang for fruit trees,fruit drop test by near the branches of the apricot fruit position with three to the acceleration sensor,data acquisition system is used to analyse the acceleration signal synchronization acquisition and indirect measure the fruit fall off in front of the shed and the acceleration of the instantaneous.In the experiment,two high-speed cameras were placed vertically and synchronously recorded the whole process before and after the vibration of the apricot fruit.The high-speed video technology applied to apricot fruit harvest vibration experiment,track,record in detail the fruit in the process of loss before and after motion,ms level time image segmentation to guarantee the precision of test process and the accuracy of the data.In the process of image processing,it is necessary to transform the pixel coordinate system to the actual 3D coordinate system of the ground,and establish the transformation relation expression.Through the PCC software reads and records the fruit under several different frames before and after the loss of pixel coordinates,on the basis of establishing the coordinate conversion expression,will record the pixel coordinates can be converted into the ground the value of the actual coordinates calculated apricot fruit off instantaneous acceleration of38.24·m s^-2,fall off speed of2.072s·m ^2-,off inertial force of8.49?10^-3 N,fall off the energy of4.01?10^-2J.From the vibration of high-speed camera video harvested fruit that fruit before shedding torsional oscillation,apricot fruit every swing to reverse time,will be connected to the peduncle around outside from the part of the final apricot fruit from the intermediate position of the connected with peduncle’s for complete separation,thus complete the fall off of the fruit harvest.