Research On Vibration Transmission Characteristics Of Wine Grape Plant

Grape industry is one of the characteristic fruit advantageous industries and agricultural pillar industries in Xinjiang,which has significant economic and ecological value.As of 2015,the wine-growing area has reached 40 000 hm~2,however,its harvesting is still completed manually.Although foreign developed countries have already achieved mechanized harvesting for wine grapes,whose wine grape tree style is trunk-shaped primarily,while the tree style in Xinjiang is multiple main vine fan-shaped tree,there are two large differences in vibration transmission characteristic between them.Thus,this paper aims to explore the vibration transmission characteristics of the multiple main vine fan-shaped wine grape plants in Xinjiang,and provide reference for the design and optimization of the shaking mechanism of wine grape harvesting machinery in Xinjiang.On the basis of the analysis for the current research status of mechanical vibration harvesting test,tree dynamics analysis and tree vibration transmission law,the double main vine regular fan-shaped wine grape planted extensively in northern China was identified as the subject of this study through field research and literature review.The basic structural parameters of the tree were measured and statistically analyzed,and the distribution of basic structure parameters of the plant was obtained.Three material properties including water content,density and elastic modulus of main vines and fruiting branches of the wine grape plants were measured,and the distribution laws of them were obtained.Through theoretical analysis,the vibration differential equations of the plant were established,and the formulas for solving the resonance frequency of each branch of the plant were obtained.Through the laser scanning test of the plant,the plant surface structural grid information was extracted,and the 3D solid model of wine grape plant was established through reverse engineering parametric modeling method.Through dynamic modal and harmonic response simulation analysis of the plant 3D solid model,the natural frequencies distribution,mode shapes,and resonance frequencies distribution of wine grape plant in the frequency range of 0 Hz to 30 Hz were obtained,and the excitation frequencies that can make the plant achieving a better vibration response were determined.Through the indoor plant hammering test,the vibration spectrum characteristics of plant and the transmission law of vibrations on plant were analyzed,the vibration transmission characteristics of wine grape plant were revealed,and better vibration parameters and methods for vibratory harvesting of wine grapes were finally obtained.the test results showed that:1)The vibration energy distribution of plant main vine and fruiting branches at the frequencies of 9 Hz,14 Hz,and 22 Hz were relatively larger,thus,the frequencies including9 Hz,14 Hz and 22 Hz could be selected as the excitation frequencies of the shaking mechanism when harvesting wine grapes,and the correctness of the simulation results was also verified by this conclusion.2)The vibration on the plant vines was transmitted in the form of wave,and its transmission law had nothing to do with excitation force and position.Most of the vibration energy was absorbed by the plant roots and its connecting soils When the plant was excited near the ground,thus,to avoid excessive excitation energy loss by the plant roots and its connecting soils,when designing a shake mechanism for wine grapes,its shaking parts should not be too close to the roots of the plants;When the one-third position of the main vine was excited,both the main vine and the resulting branches of plant were able to achieve better vibration transmission effects.The vibration energy could be transmitted between the main vines through the wire and the main root,but the vibration response of the main vine which was excited was significantly greater than that of the adjacent main vine,thus,when designing the shaking mechanism for wine grapes,in order to improve the plant's vibration transmission efficiency,the shaking mechanism should ensure that each main vine will be excited.