桑葚机械振动收获参数优化与试验研究

Abstract

The mechanized harvesting of mulberry is important for its production. In the process of harvesting, it is considered not only the mechanical damage of mulberry fruit but also its harvesting efficiency. It is very important to improve the vibration harvesting efficiency of mulberry. In this study, modal analysis of mulberry trees and harmonic response analysis of branches were carried out to determine the harvesting frequency of the branch's vibration and other parameters. The effects of excitation frequency and vibration position on the triaxial acceleration of the mulberry branch at different positions were analyzed by vibration test. Then the triaxial acceleration of branches at different positions was analyzed. The conditions of the mulberry fruit shedding were obtained through theoretical analysis. Through the 20-order modal analysis of mulberry, it is concluded that a better vibration effect can be achieved when the vibration frequency is controlled at 4-16 Hz. According to the harmonic response analysis, the best excitation frequencies are 5-6 Hz, 10-13 Hz, and 14-16 Hz. The harmonic response analysis of fruit branches was carried out, and the stress of fruit stalks at 5 Hz, 10 Hz, and 15 Hz were analyzed. The result shows that the maximum stress is 2.9252×107 Pa, the excitation position is the first-order branch, and the excitation frequency is 15 Hz. The frequencies obtained from modal analysis and harmonious response analysis were used to conduct experiments. When the excitation frequency was 15 Hz, the triaxial accelerations aX, aY, and aZ were 2.12 g, 4.16 g, and 3.99 g, respectively, which were more conducive to the shedding of mulberry fruits.