Research On Dynamics Characteristics Of Rigid-flexible Coupling Of Camellia Oleifera Picking Mechanism-fruit Tree

Camellia oleifera,a unique woody oil tree species in China,its Planting area has enlarged in recent years.However,at present,the picking of Camellia oleifera is mainly manual,with low efficiency and high labor intensity,which seriously restricts the development of the Camellia oleifera industry.Hunan is the main producing area of Camellia oleifera.Therefore,it is of great engineering significance to study the rigid-flexible coupling dynamic characteristics of Camellia oleifera fruit picking mechanism and fruit trees based on the morphological and structural features of Camellia oleifera tree.The selection of working parameters of the camellia fruit picking mechanism designed in this paper will directly determine the effect of picking.Based on this,this paper analyzes the fruit picking theory and uses ADAMS simulation software to operate dynamic simulation of rigid-flexible coupling on the picking mechanism-fruit tree vibratory system,and conducting experimental research.According to the working principle of the picking mechanism,a harvesting kinetic model of "Camellia oleifera fruit picking mechanism-fruit tree" was established,and the vibration differential equations of the system were listed.The amplitude and phase angles and displacement expressions of the system were obtained by solving.According to the growth characteristics of Camellia oleifera in Hunan,a vibration mechanical model of short-stemmed fruit was studied.By solving the fruit motion equation and analyzing the fruit shedding conditions,the inertial force generated by the fruit during the movement is related to the working rotational speed of the eccentric block and the amplitude of trunk.the higher the rotational speed,the larger the inertial force of the fruit,the larger the amplitude,and the larger the amplitude of the fruit inertial force,which provides a reference for the design and simulation of the subsequent picking mechanism.Based on plant fractal theory and field survey of morphological characteristics of Camellia oleifera tree,ang measuring the size parameters of the primary stem,secondary side branches,and tertiary side branches of Camellia oleifera tree.and a three-dimensional mechanical model of Camellia oleifera tree was established for the purpose of rigid-flexible coupling simulation using Solidworks software.This paper introduces the Camellia oleifera fruit picking mechanism and establishing the three-dimensional modelingBased on ANSYS and ADAMS software,a three-dimensional flexible body model of Camellia oleifera tree was established.A rigid-flexible coupling model of "picking mechanism-fruit tree" was built in ADSMS.Adding the constraints of rigid-flexible coupling model and setting the working parameters of the picking mechanism based on the actual situation to operate dynamics simulation of rigid-flexible coupling on vibratory system and research vibration response characteristics of Camellia oleifera tree under different excitation frequencies and different clamping heights were studied.A picking test is performed on the picking mechanism to determine the feasibility and effect of the picking mechanism.By designing Orthogonal experiments and analyzing the results of picking tests by means of range analysis and analysis of variance,to obtain the relationship between the fruit drop rate、the flower drop rate and the working parameters The results show that when the picking frequency is at 35～41 Hz,a higher fruit drop rate can be obtained,and the fruit drop rate is above 85%.As the excitation frequency increases,both the fruit drop rate and the flower drop rate increase first and then decrease;as the clamping height increases,the fruit drop rate gradually increases and the flower drop rate gradually decreases.The experiment also showed that under the condition of the significance level of 0.01,the clamping height and the excitation frequency had a high and significant effect on the fruit drop rate and the flower drop rate.Multi-index analysis was performed by comprehensive scoring method,and the optimal combination parameters were obtained at an excitation frequency of 38 Hz and a clamping height of 1300 mm.