| 基于时频和功率谱密度的移栽机振动特性测试与分析 |
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| 引用本文： | 耿令新,李康,庞靖,金鑫,姬江涛.基于时频和功率谱密度的移栽机振动特性测试与分析[J].农业工程学报,2021,37(11):23-30. |
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| 作者姓名： | 耿令新 李康 庞靖 金鑫 姬江涛 |
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| 作者单位： | 河南科技大学农业装备工程学院，洛阳 471003 |
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| 基金项目： | 国家重点研发计划资助项目（2017YFD0700800） |
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| 摘 要： | 针对移栽机机械受激励产生振动影响取苗、顶苗工作稳定性的问题,该研究以2ZTT-2型顶夹式气动蔬菜移栽机为研究对象,对移栽机的振动特性进行研究。采用时频分析和功率谱密度分析相结合的方法,得到信号能量在时间轴以及频率轴上的分布特征,并运用锤击法,研究了不同工况下各测点主要频率与该测点代表运动部件的前5阶固有频率之间的对应关系。试验结果表明:取苗摆动装置运动、苗盘横移是移栽机的主要振源,取苗机械手开合、顶苗机构伸缩是振动的次要原因。振动信号频率主要分布在低频频率(0～10 Hz)处,取苗摆动装置运动时加速度振动幅值为5.43 m/s2,整机运转时为1.71 m/s2,振幅下降了68.51%,并且移栽机取苗摆动装置运动所引起的主要振动频率(6.10 Hz)与对应测点处的第5阶固有频率(6.25 Hz)相近,发生了共振现象。研究结果可为移栽机振动特性分析、结构优化设计提供参考。
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| 关 键 词： | 农业机械 振动 移栽机 锤击法 时频分析 功率谱密度 固有频率 |
| 收稿时间： | 2021/3/10 0:00:00 |
| 修稿时间： | 2021/6/30 0:00:00 |
Test and analysis of vibration characteristics of transplanting machine based on time frequency and power spectral density |
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| Geng Lingxin,Li Kang,Pang Jing,Jin Xin,Ji Jiangtao.Test and analysis of vibration characteristics of transplanting machine based on time frequency and power spectral density[J].Transactions of the Chinese Society of Agricultural Engineering,2021,37(11):23-30. |
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| Authors: | Geng Lingxin Li Kang Pang Jing Jin Xin Ji Jiangtao |
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| Institution: | College of Agricultural Equipment Engineering, Henan University of Science and Technology, Luoyang 471003, China |
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| Abstract: | A large-amplitude vibration commonly occurs in most agricultural machinery at present in China. The resulting high failure rate and low reliability have posed great damage to the structural safety and driver comfort of the machine. Many efforts have been made on the vibration modes and testing in agricultural harvesting machines. But only a few focused on the vibration of planters, especially a high-speed transplanting machine. Most previous tests show that the variable speed rotation or swing of the mechanism can significantly cause the impact vibration and inertia force of components, particularly with the increase of picking speed. As such, there is a huge decline in the success rate of picking seedlings, while leading to a high missing rate of seedlings, due mainly to the operational instability and high errors. However, no good solutions were reported to deal with that so far. In this study, taking a top clamp-type pneumatic transplanter (2ZZT-2) of vegetable as the research object, the vibration characteristics of a transplanter was investigated using the time-frequency analysis. A dynamic signal instrument (DH5902) and 3-way acceleration sensor (356A16 type) were first used for the data acquisition. A time-frequency analysis was performed on the MATLAB software, where the power spectral density was adopted to analyze the vibration data. The distribution characteristics of signal energy were obtained on the time- and frequency-axis. Secondly, the local resonance was also verified for the test components. The hammering and multi-point excitation were utilized to determine the response of hammering excitation and vibration data in the measuring points of components. Correspondingly, a specific relationship was obtained between the frequency of each measuring point and the first five natural frequencies. The experimental results showed that the main sources of vibration in the transplanter were derived from the swing of the mechanical arm and the transverse movement of the seedling plate. The secondary sources of vibration were the opening and closing of the seedling picking manipulator, and the stretching of the top seedling mechanism in the whole machine. The energy intensity of vibration was distributed mainly at the low frequency (0-10 Hz) during the transplanting operation. The amplitude was 5.43 m/s2, when the seedling manipulator swung, and 1.71 m/s2 when the whole machine working, indicating the amplitude decreased by 68.51% than before. In addition, the vibration frequency (5.49 Hz) caused by the swinging of the seedling taking manipulator was close to the fifth natural frequency (6.10 Hz) at the measuring point, when the transplanter was working normally, indicating the resonance occurred. The finding can provide a sound reference to improve the vibration performance for the high reliability of a transplanter. |
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| Keywords: | agricultural machinery vibration transplanter hammering method time-frequency analysis power spectral density natural frequency |
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