农机装备作业人员手臂振动生物力学模型及动态响应特性研究

Hand-transmitted vibration does great harm to the physical and psychological health of the operators of agricultural machinery equipments. However,the current study focuses primarily on vibration exposure of the workers and diagnosis and treatment of the hand-arm vibration disease. The key and fundamental issues, such as the dynamic characteristics, the absorption and transmission characteristics of vibration energy, remain uncertain and call for attention. Taking the hand-held rice transplanter and harvester as the research object, taking into account the vibration excitation, the human body, and external environmental factors, the hand-transmitted vibration of the handle and steering wheel will be measured and evaluated comprehensively. Based on the biomechanical characteristics and vibration dynamic theory, the vibration biomechanical and finite element dynamic model of the human hand-arm system will be established innovatively. Afterwards, the theoretic calculation method, simulation analysis, and various experimental methods will be adopted to evaluate the dynamic characteristics, the absorption and transmission characteristics of vibration energy, and the vibration response. The influence of various factors, such as the vibration frequency and amplitude, on the transmission characteristics and the vibration response will be explored. Consequently, the transferring behavior of vibration energy in the hand-arm system will be revealed. Finally, the parametric finite element model of the object will be established. On the basis of the model, the key modal frequency and its sensitive parameters will be optimized dynamically to control the fundamental frequency of the object. In order to reduce the hand-arm vibration strength and mitigate its adverse impacts on the hand-arm system, the fundamental frequency of the object should dodge the peak regions of the impedance and vibration transmissibility of the arm. The research can provide important references for optimization design and vibration control of the vibrating machineries and occupational health surveillance of the operators.

农机装备手传振动是危害作业人员身心健康的重要因素，但目前的研究主要侧重于对作业岗位接振、振动病诊断治疗等进行初探，而对手臂动态特性与振动能量吸收传递特性等关键基础问题缺乏系统深入的研究。本项目针对水稻插秧机与收获机的操纵把手与方向盘，综合考虑振动激励、人体自身及外部环境因素，完成机具手传振动的综合测评，并根据手臂生物力学特性与振动动力学理论，构建其振动生物力学模型与有限元动力学模型，从理论计算、仿真分析及试验角度深入分析其动态特性、振动能量吸收传递特性及振动响应，探究振动频率与幅值等因素对其振动响应与传递特性的影响，揭示振动能量在手臂内的转移规律。最后，构建机具把手与方向盘的参数化有限元模型，采用模态分析法对关键模态频率及其敏感参数进行动态优化，控制把手与方向盘的振动基频，从而避开手臂机械阻抗与振动传递率峰值区域及敏感频率范围，减少振动对人体手臂系统的不良影响。项目研究可为机具振动控制优化及作业人员职业健康监护提供重要参考。

农机装备手传振动问题是危害作业人员身心健康的重要因素，具有重要的理论研究与工程应用价值，但现有研究主要侧重于对振动作业岗位接振情况及手臂振动病的诊断与治疗进行调查研究，而对人体手臂系统的动态特性、振动能量吸收与传递特性等关键基础问题则缺乏系统深入的研究。本研究主要以某插秧机与拖拉机两种重要农机装备为研究对象，首先对现行ISO5349-2001测评体系进行补充与完善，并据此对插秧机操纵扶手与拖拉机方向盘的振动进行测试与评价，估算机具手传振动接触危险度，结果发现，试验用插秧机引发手传振动病的风险较低，而拖拉机引发手传振动病的风险较高，尤其是低挡位作业时，驾驶员患手臂振动病的暴露年限较短，工作条件更为危险。之后，采用有限元仿真与试验研究相结合的方法对作业人员手臂系统的生物动力学特性、振动能量吸收与传递特性、手臂的振动响应及其与振动激励的关系等关键基础问题进行了系统深入的研究，结果发现，手臂整体前六阶模态频率范围为0.5-5.6Hz，手指部位振动位移最大；手掌对小于25Hz低频振动能量吸收较差；手臂对3.6Hz、5.6Hz、10Hz、25Hz、36Hz、50Hz等频率点的振动比较敏感；驾驶员手背y轴与z轴振动强度明显大于x轴（垂直于手背方向）的振动，振动从手背传递到手臂时呈逐渐衰减的趋势；握力水平、振动强度以及推力水平对手臂振动传递特性均具有显著影响，尤其是当手臂肘角为180°时，其影响更为显著。最后，为了控制机具操纵扶手与方向盘的手传振动，采用有限元参数化建模的方法对扶手与方向盘的关键模态频率及敏感参数进行了动态优化，结果表明，该方法可以有效控制扶手与方向盘的模态频率与振动基频，使其避开手臂敏感振动频率范围，从而减少振动对人体手臂的不良影响。项目研究成果不仅为机具的结构改进与优化提供了一种新思路，同时还为作业人员的职业健康监护、手臂振动病的早期诊断与防治提供了重要参考。