Research On Vibration Harvesting Method And Device Development Of Red Jujubes

Red jujube is one of the characteristic fruits in China.The mechanization of red jujube will eventually emerge as one of the most promising research areas in China with the development of red jujube planting areas and the enhancement of orchard management.However,the red jujube harvesting equipment now only uses predetermined vibration frequencies and amplitudes to collect red jujubes from jujube trees of various diameters.This led to low net picking rates and fruit gathering efficiency because it overlooked the vibratory variations amongst red jujube of various diameters.In response to the aforementioned issues,the vibration parameters of jujube trees with different diameters were studied and a harvesting device of red jujube was designed in this research.The device could harvest red jujube trees of different diameters by different vibration frequencies and vibration amplitudes.The research will provide theoretical basis and technical support for realizing mechanical harvesting of jujube.The main research contents and conclusions of this research are as follows:(1)Optimization of jujube tree vibration parameters for various diameters.Through the modal analysis of three kinds of jujube trees,it was discovered that the vibrating branches of jujube trees with various diameters could produce the greatest amount by appropriate vibrations frequencies of excitation force.By harmonic response analysis,the vibration frequency ranges of jujube trees with various diameters were determined.Vibration tests were used to determine the optimal combination of vibration characteristics for jujube trees with various diameters.The jujube tree vibrated at a frequency of 30 Hz,an amplitude of 15.00 mm,and a duration of 9 seconds when its diameter was 30 mm.The jujube tree vibrated at a frequency of 16.21 Hz,an amplitude of 12.52 mm,and a duration of 9 seconds when its diameter was 50 mm.The jujube tree vibrated at a frequency of 6.18 Hz,an amplitude of 15.00 mm,and a duration of 9 seconds when its diameter was 70 mm.Therefore,the vibration parameters were consistent with the simulation results,which provided a basis for the subsequent design of jujube vibration harvesting devices and vibration harvesting tests.(2)Design a vibration harvesting device for red jujubes based on ADAMS and ANSYS.The vibration mechanism of red jujube was designed,and ADAMS was used to simulate its dynamics.The results demonstrated that the acceleration at the end of the vibration rod had tendency to rapidly increase and decrease,which was advantageous for the vibration of red jujube.The collecting mechanism was designed,and the structure simulation was carried out by ANSYS.The results showed the mechanism could satisfy red jujube collection demand.The design therefore served as the hardware foundation for the future vibration harvesting tests.(3)A trunk measurement method of red jujube based on improved PSPNet was proposed.The trunk segmentation method based on improved PSPNet and the diameter measurement method based on centerline were proposed.The results revealed that the average trunk diameter measurement accuracy was 96.33%,the average relative error was 3.67%,and the average absolute error was 1.27 mm.As a result,the improved method not only accurately measured the trunk diameter and satisfied practical requirements,but it also proved the value and dependability of the deep learning algorithm in the application of measuring trunk diameter.(4)Manufacture of jujube vibration harvesting device and vibration harvesting test.Through the vibration test and collection test of red jujube trees with different diameters,the red jujube trees with approximate diameters from 29.15 mm to 31.26 mm,from 49.56 mm to52.34 mm and from 65.23 mm to 73.25 mm were obtained,and the average percentage of net plucking were 93.98%,94.71% and 94.33% respectively,and the average efficiency of fruit collection were 95.78%,89.43% and 85.04% respectively.Therefore,the machine on the vibration and collection of red jujubes was effective and could meet the production requirements.While the design of jujube vibration harvesting device based on different trunk diameters and the measurement method of jujube trunk diameter based on improved PSPNet were also effective and reliable.