| 悬挂农具对电液悬挂系统拖拉机振动的影响 |
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| 引用本文： | 承 鉴,迟瑞娟,毛恩荣.悬挂农具对电液悬挂系统拖拉机振动的影响[J].农业工程学报,2015,31(7):24-32. |
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| 作者姓名： | 承 鉴 迟瑞娟 毛恩荣 |
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| 作者单位： | 中国农业大学工学院,北京 100083,中国农业大学工学院,北京 100083,中国农业大学工学院,北京 100083 |
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| 基金项目： | 高等学校博士学科点专项科研基金资助项目（20130008110042）;"十二五"国家科技支撑计划资助项目（2011BAD20B02） |
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| 摘 要： | 悬挂农具设备的拖拉机在行驶过程中的振动会加剧,有时甚至产生很大的俯仰运动。为了研究悬挂农具的存在对拖拉机振动特性的影响,该文在对拖拉机进行运动学和动力学分析的同时,首次详细分析了悬挂机构的运动及受力情况,从而建立了带有悬挂农具的大功率拖拉机整机振动数学模型;用Matlab仿真了拖拉机受到条形水泥障碍激励时的振动情况。研究表明:农具的存在使拖拉机前轮动载系数由O.26增大到0.55;空载拖拉机垂直振动频率为3 Hz,带农具的拖拉机垂直振动频率为2.5 Hz;农具的存在使得拖拉机的俯仰振动显著增加,频率为4.8 Hz;由于悬挂系统的运动与拖拉机机体振动的非线性耦合,一定条件下会表现出频率为10~15 Hz的第3振型的振动;农具的振动使得电液悬挂系统下拉杆铰接点处的力发生相应变化,其垂直分量的大小与农具质心垂直加速度之间存在较好的线性关系。仿真结果与试验结果相吻合,验证了所建数学模型的正确性。所得到的上述结论为拖拉机主动减振控制提供了理论依据。
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| 关 键 词： | 拖拉机 振动 悬挂 机构 数学模型 仿真 振型 |
| 收稿时间： | 2015/1/11 0:00:00 |
| 修稿时间： | 2015/3/19 0:00:00 |
Influence of hanging farm implement on vibration of tractor with electro-hydraulic hitch system |
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| Cheng Jian,Chi Ruijuan and Mao Enrong.Influence of hanging farm implement on vibration of tractor with electro-hydraulic hitch system[J].Transactions of the Chinese Society of Agricultural Engineering,2015,31(7):24-32. |
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| Authors: | Cheng Jian Chi Ruijuan and Mao Enrong |
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| Institution: | College of Engineering, China Agricultural University, Beijing 100083, China,College of Engineering, China Agricultural University, Beijing 100083, China and College of Engineering, China Agricultural University, Beijing 100083, China |
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| Abstract: | Abstract: With the increase of the speed of high-power tractors, the tractor's vibration problem has become more and more prominent in recent years, since tractors often travel on rugged roads. High-power tractors mostly work with farm implements hung by hydraulic hitch system. The hanging farm implements are raised to the highest point in transit. When the tractor is travelling on the rugged road, the vibration of the tractor with a farm implement will be more intense for the existence of the hanging farm implement sometimes would bring a great pitch vibration. This paper discussed the effect of the existence of the farm implement on the vibration characteristics of the tractor. For the first time, the movement and stress distribution of the hitch system and the farm implements were analyzed in detail, besides that of the tractor's body. The mathematical vibration model of the tractor with a farm implement was established. And then the incentive mathematical model of the concrete barriers was established and the process of the tractor driving over obstacles was simulated with the Matlab based on the mathematical model. Variation curves of each key point were got and some conclusions were obtained by the simulation. The front tire's dynamic load and dynamic load coefficient increased significantly because of the existence of the farm implement. The front tire's dynamic load coefficient increased from 0.26 to 0.55, which seriously affected the safety of the driving. When the tractor encountered obstacles, low frequency vibration had obviously been strengthened. In both cases of load and no-load, the first vibration mode of the tractor was the body's vertical vibration, and the second vibration mode of the tractor was the body's pitch vibration. Without the farm implement, the tractor's vertical vibration frequency was 3 Hz, and it became 2.5 Hz with the farm implement. In case of no-load, the tractor's pitch vibration was hardly apparent. When the farm implement was hung up, the tractor's pitch vibration was significantly enhanced by the farm implement, and the frequency of that was 4.8 Hz. Because of the nonlinear coupling between the vibration of the tractor and the motion of the hitch system, the third vibration mode appeared under certain conditions, the frequency of which was between 10 and 15 Hz. Both the performances of the second and the third vibration mode of the tractor with farm implement would be harmful to the driver's comfort and the safety of the tractor. The vibration of the farm implement made the force of the lower pull rod's hinge point of the electro-hydraulic hitch system changed correspondingly. There was a good linear relationship between the vertical component of the force and the vertical acceleration of the farm implement's centroid. Therefore, we could use the vertical force instead of the acceleration to represent the vibrational state of the tractor when we designed the active vibration control system of the tractors later on. The simulation results agreed well with the experimental results, which verified the correctness of the mathematical model. The methodology and conclusion provide a theoretical basis for the tractor vibration control. |
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| Keywords: | tractors vibrations suspensions mechanisms mathematical models simulation vibration mode |
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