人体平衡功能测试系统研究进展

平衡功能是人体的一项重要功能,日常生活中的各种动作都依赖有效的平衡作保障,人体姿态平衡的正常维持依赖于前庭、视觉和本体感觉系统输入以及中枢神经系统的整合。章较详细地介绍了目前人体静态、动态姿势平衡测试系统的研究现状、平衡评定的实验及应用现状,最后从劳动科学和人机环境与安全工程的角度考虑,着眼于林业工人在林区作业时施加给作业很大的劳动负荷而影响人体的平衡功能提出一些初步的构想。     

家具封边作业的人体仿真测量与优化

目的对家具封边岗位的疲劳度进行测试,以人体工程学原理作为参考依据,对单边直线封边岗位工人的作业疲劳度进行深度剖析和优化。方法使用动素分析对封边作业的每一个连续动作进行分解,记录无效动作。再应用人体仿真软件3DSPSS构建虚拟的工厂环境,输入采集到的各种的人体尺寸和典型的作业姿势,并给虚拟的人指派任务,从而输出人体各种姿势下各部位的身体疲劳数据。结果工作岗位上人与人之间作业的不协调会增加无效动素,也增加了身体疲劳度;不断重复的弯腰动作会增加腰椎盘间的压力从而易造成腰椎间盘损伤;正常的直立或者前俯动作的腰椎间盘压力比弯腰、下蹲等作业姿势的压力较小;腿部的弯曲可以有效增大腿部和脚步的承受能力以及减少腰椎间盘压力。结论除了对工人的动作进行优化,调整工序和优化工人的某些不良的动作习惯是非常有效减缓疲劳的措施。     

基于OWAS的人工破拆作业肌肉疲劳骨骼风险分析

目的 探究不良工作姿势对人工破拆作业人员肌肉骨骼损伤(MSDs,Musculoskeletal Disorders)的影响.方法 本文采用工作姿势分析系统(OWAS,Ovako Working Posture Analysis System)对作业人员的不良姿势出现的百分比和负重情况进行分析与评估.结果 数据显示作业人...     

BSR—1型人体平衡功能测试仪及其测试指标

章介绍由北京林业大学工学院人机工程研究室研制的BSR－1型人体平衡功能测试仪，该测试仪由测试平台、计算机和人体平衡功能专用分析软件组成，主要用于便携式林业机械作业时人体负荷、人体生理和心理因素以及机械几何参数对人体平衡功能影响规律研究。章具体阐述该测试仪的系统构成、测试平台测量人体重心动摇的工作原理、测试仪的主要测试指标及其计算方法和人体平衡功能专用分析软件特点。     

无动力下肢负重外骨骼人机动力学及其储能元件刚度优化EI北大核心CSCD

为提高人体搬运效率,降低人体关节损害,提高外骨骼能量利用效率,基于人机动力学对一种无动力辅助负重下肢外骨骼的储能元件刚度进行优化。应用牛顿-欧拉动力学方程建立人机耦合动力学模型,得到各关节力矩与大小腿长度和质量、关节转角及弹簧刚度关系的数学模型。将三维动作捕捉系统采集的角度数据代入动力学方程中,通过MATLAB进行计算得到关节力矩动态变化规律。建立人机系统各部分的能量流动模型,并进行步态周期内的能量流动分析,以储能元件刚度为参数,储能元件的能量流动为约束条件,各关节平均力矩最小为目标建立优化模型,通过与AnyBody人体仿真软件获得的人体模型作对比验证优化结果的正确性。结果表明,穿戴优化后外骨骼减轻了下肢着地时对人体的冲击,有效降低了人体能耗和下肢关节转矩。     

特定作业环境下作业姿势的研究

针对某厂实际生产过程中的铆接工序,研究了作业环境对作业姿势的限制,提出了考虑人因的作业规划,设计了3种人体作业姿势方案.利用人因工程学原则,分别对每种姿势进行了可行性分析;利用人因软件对各方案进行了视觉分析、手的操作范围分析和人体负荷计算.在对各方案综合分析评价的基础上,结合实际生产过程中的设备情况,确定了该力工环境下最优的作业姿势.     

静态双手拉车作业的肌肉疲劳分析与MET建模

目的为分析静态双手拉车作业肌肉疲劳的发展情况。方法设计双手拉车模拟试验,9名大学生参加试验,通过测量试验前后被试双手拉力大小(MVC、F),并记录试验时间(MET)和主观疲劳评价值(RPE),探讨两种脚部姿势下静态拉力作业肌肉疲劳发展过程;并依据试验数据建立疲劳的MET预测模型。结果拉车作业使双手的拉力显著下降;脚部姿势仅显著影响下肢RPE,对MVC、MET、F以及上肢和腰部RPE影响不显著;前腿的疲劳感显著高于后腿;所建MET预测模型与现有模型具有一致性,其预测值与实测值偏差较小。结论静态双手拉车作业会产生肌肉疲劳;脚部姿势对拉力大小不产生显著影响;所建MET模型能反映静态双手拉车的肌肉疲劳发展,能为设计拉车作业任务提供针对性依据。     

仿脊柱隔振器振动特性分析

受人体脊柱负重减振作用的生物学启发,设计了一种多层节状连接仿生隔振器.分析不同设计参数对隔振器静态刚度和承载能力的影响,由拉格朗日动力学公式建立了隔振系统动力学方程,利用谐波平衡法对动力学方程进行求解,分析不同设计参数对隔振器位移传递率的影响,通过四阶龙格库塔法求出数值解并与谐波平衡法的解析解进行对比,验证了该研究结论...     

基于JACK的手机使用场景颈部及上肢关节舒适度评价分析

目的探索人体坐姿状态下握持手机最舒适姿势。方法基于人因工程学软件JACK,创建了三组不同百分位数字人P_S、P_(50)和P_(95),探究了颈部关节、肩部关节和肘部关节弯曲角度对颈部及上肢握持手机姿势舒适度的影响规律。并在Porter评价模型的基础上针对人体握持手机姿势构建了颈部及上肢关节舒适度评价模型。以颈部关节、肩部关节和肘部关节弯曲角度相对于Mode值的偏离值作为三组舒适度评价指标,并采用AHP法确定了三组指标的权重,根据所构建的颈部及上肢关节舒适度评价模型进行了舒适度评价。结果视距保持不变,随着颈部关节弯曲角度的增大,颈部及上肢关节舒适度呈先递增后递减的趋势。当视距在35 cm～40 cm之间,且颈部关节弯曲角度在17°～19°之间,肩部关节弯曲角度在12°～14°之间,肘部关节弯曲角度在120°～121°之间变化时,人体握持手机颈部及上肢舒适度指数大于0.8,为较舒适状态。结论该评价模型能够有效快速的进行关节舒适度评价。通过调节使用手机时关节弯曲角度,可以预防颈部及上肢关节疾病的产生。     

基于OWAS方法的选煤厂工人肌肉骨骼损伤分析

探讨选煤厂拣矸作业中危险姿势对工人肌肉骨骼损伤的影响。通过问卷调查和工作姿势分析系统（OWAS）对工人不良作业姿势重复出现的比例以及身体损伤状况进行评估与分析。结果显示工人背部和颈部出现不良作业姿势的比例、危害和损伤程度较高。这与疲劳自觉症状调查和OWAS系统分析所得出的结果基本一致。采取恰当的轮岗方式,增加座椅以及防护装备可有效降低工人肌肉骨骼的损伤程度,同时会更好的提高工作表现并减少工伤事故的发生。     

A Better Posture Strategy for Fingertip Force and Finger Coordination during a Daily Activity

An effective jar opening movement requires not only the complex integration of the thumb and fingers but also good body segment coordination dependent on the body posture. However, few studies have focused on the effect that jar opening posture has on the finger force integration when the fingertips are grasping the jar in their natural positions, rather than fixed ones, and few have considered the role of the global motor in this task. Forty‐two healthy young subjects participated in this study and performed the jar opening movement using a custom instrument with three opening postures. The results showed that the resultant force and overall torque of the right hand significantly increased from the vertical to the off‐table posture. The thumb produced the greatest resultant, tangential and normal forces when the off‐table posture was used. Further, the average normalized normal forces of the thumb and middle–ring–little finger group were greater for the off‐table posture than those for the vertical posture, whereas no difference was found for the index finger. The normal forces were 3.02–3.36 times greater than the tangential forces for the three finger groups. The thumb had the greatest torque contribution and produced the same torque contributions for all the three postures. The torque contributions of the index finger and the middle–ring–little finger group were 0.56–0.96 times smaller than that of the thumb. This study found a better posture strategy for the young subjects to open a jar with the off‐table posture while sitting, and this was also the best opening posture when comparing the overall torque in this work with that reported in previous studies, no matter whether the subjects were standing or sitting or whatever type of finger group was defined. However, the effect of grasp type and the middle, ring and little fingertip force need to be clarified in future studies. Copyright © 2014 John Wiley & Sons, Ltd.     

铸件打磨工人姿势分析及改善研究

为设计能减轻铸件打磨工人工作姿势负荷的工作平台,首先在现场录制打磨工作的视频,然后运用OWAS(Ovako working posture analysis system)分析视频中打磨作业的工作姿势,发现工人在打磨铸件时须长时间保持背部和腿部弯曲的姿势,86%的工作姿势劳累等级为迫切需要改进的AC3级和AC4级。针对姿势分析发现的问题,结合人体尺寸数据和打磨作业的现实约束条件,设计适用于打磨作业的工作平台,并采用Jack软件对改善后打磨工人的工作姿势进行验证。结果表明,在工作平台进行打磨工作时,AC1级姿势占42.6%,AC2级占57.4%,基本消除AC3级和AC4级姿势。打磨工人的工作姿势得到显著改善。     

温度突变环境下人体平均温度变化及热感觉预测

分析了利用Gagge教授“两节点模型”求解人体平均温度的方法,然后根据人体与环境间热交换的平衡建立了一个简单的人体温度调节模型——“一节点模型”,避免了求解人体平均温度时所需要的复杂计算,该模型不但减少了计算求解的工作量,而且结果与“两节点模型”间有着很好的一致性;作为实际应用,利用该模型制作了温度突变环境下人体温度求解表格及曲线,总结了在该环境下人体温度变化规律,从而找到了热感觉指标TSENS在温度突变环境下的实用途径。     

The effect of hemodialysis session on postural strategies in older end‐stage renal disease patients

Patients suffering from end‐stage renal disease experience multiple disabilities, such as muscle wasting, weakness, higher postural sway, and fall rates compared with healthy population, which has a negative effect on physical functioning and autonomy. The vital treatment of hemodialysis is recognized to induce important post‐hemodialysis fatigue, hypotension, cramps, and headache due to the rapid fluid redistribution, among others. Nevertheless, even the well‐known negative effect of aforementioned consequences of hemodialysis treatment, its effect on physical function, especially postural balance, is unclear. Thus, this study hypothesized the adverse effect of hemodialysis treatment on postural sway in 12 end‐stage renal disease patients (mean age 63.3 ± 11 years) through the analysis of center‐of‐pressure (COP) trajectories recorded before and immediately after hemodialysis session. Evident postural alterations were observed at post‐hemodialysis balance assessment for COP position‐based (Fs < 7.7, P < 0.02) and COP velocity‐based variables (Fs > 2.33, P < 0.05), without changes in complexity of COP time series in anteroposterior and mediolateral directions. These results suggest that period after hemodialysis treatment is particularly unsafe, as evidenced by important disability in postural control, and highlight the importance of the medical support and falls‐related prevention strategies of these older frail patients after hemodialysis treatment.     

几种静态姿势的负荷评价与工作设计

以２５名大学生志愿者为对象，通过实验室模拟生产中常见的几种静态姿势，测定和分析了他们的肺通气量、心率及Ｂｏｒｇ量表分值的变化。结果发现自然坐位和站位情况下，随手臂不同程度地前伸和上举，肺通气量、心率、Ｂｏｒｇ量表分值连续地升高，至双臂９０°上举达到最高值。结果说明，肺通气量、心率及Ｂｏｒｇ量表分值均可在一定程度上反映静态劳动的负荷。手上举及手完全前伸的作业姿势无论从劳动生理还是生物力学的角度看都是不合理的，在工作上应尽量加以避免。     

三缸发动机整车怠速振动性能研究

研究基于传统四缸、横置前驱架构上更换的三缸发动机车辆在怠速工况下车内振动性能。阐述分析未加装平衡轴三缸发动机的激励及整车传递路径特性,并从整车NVH性能集成角度研究降低怠速工况下车内振动措施。研究结果表明:怠速工况下,三缸机一阶不平衡往复惯性力矩引起的怠速振动可以通过发动机的不同激励策略结合整车灵敏度特性及悬置的阻尼特性来消除;而降低1.5阶主燃烧激励引起的怠速振动,除降低发动机负载需求和通过降低悬置X向动刚度获得更低的Pitch模态频率及更高隔振性能外,还可以通过优化响应点处的模态频率来实现。     

基于多尺度下塑性指数模型的结合面接触刚度计算方法EI北大核心CSCD

螺栓连接结合面的接触特性是影响机械系统动静态特性的关键。当结合面处于振动疲劳状态时,会导致阻尼增大和共振频率减小,因此建立精确的栓接结合面接触模型对研究整个机床的动态特性有着十分重要的意义。结合Greenwood和Williamson给出的塑性指数表达式、统计学的粗糙度参数和分形参数,建立了与微凸体频率序数相关的塑性指数模型,从而根据塑性指数得到微凸体弹性-弹塑性-塑性变形的临界频率序数,并基于赫兹接触理论,通过对不同频率区间内微凸体的积分得到整个结合面的接触载荷和接触刚度。最后,通过有限元仿真与试验相结合共同验证了理论模型的正确性,证明该理论模型具有较强的工程应用价值。     

The Effect of Jar Holding Posture on Finger Force and Torque during a Jar‐Opening Task for Young Females

Many young females have difficulty opening jars. Although previous studies have attempted to clarify the body posture effect during such a task, the experiments therein focused on a single digit or actions with unnatural finger positions and were further restricted to upper extremity postures. A further study is required to investigate the fingers’ coordination, as well as each subject's natural and self‐selected upper extremity posture and finger grasp location when opening a jar. This study focused on the forces and coordination of the right hand fingers during a jar opening movement under both vertical and free‐way opening postures. A jar simulator was set up to record the forces applied by finger groups (the thumb, the index–middle finger group, and the ring–little finger group) of the right hand. A self‐selected finger position and free‐arm posture of each subject were allowed. Results show that the force vectors of the finger groups were all in the counterclockwise direction for both postures. The total force and overall torque of the right hand decreased in the vertical opening posture. The thumb produced greater tangential and resultant forces in the vertical opening posture. Despite normal forces being 1.82–3.54 times the tangential forces for both postures, no difference was found for the normal force to tangential force ratio for each finger group between the two opening postures. The index–middle finger group had similar torque contributions for both postures. The torque contribution of the thumb increased (26% and 21% for vertical and free‐way posture, respectively), while the ring–little finger group torque contribution decreased (35% and 42% for vertical and free‐way posture, respectively) in the vertical opening posture. As such, the free‐way opening posture is the better strategy for young females to open a jar. Copyright © 2013 John Wiley & Sons, Ltd.     

Calculation of the stress intensity factors and nominal stresses in the plane of a crack from the opening of its edges

A method is proposed for determination of the stress intensity factors and stress distribution in the plane of a defect under an arbitrary load. It includes measurement of the opening of the edges of a developing opening mode crack at several points at a distance from its tip. The theoretical basis of the method is the equation of the energy balance of the body with a crack and the Petroski-Achenbach approach of approximate calculation of the crack edge opening, making it possible to consider arbitrary configurations of the body and the crack. The results of solution of a series of method examples confirming the accuracy and effectiveness of the proposed approach are presented.Translated from Problemy Prochnosti, No. 6, pp. 27–34, June, 1990.     

A Distributed Intrusion Detection Model via Nondestructive Partitioning and Balanced Allocation for Big Data

There are two key issues in distributed intrusion detection system, that is, maintaining load balance of system and protecting data integrity. To address these issues, this paper proposes a new distributed intrusion detection model for big data based on nondestructive partitioning and balanced allocation. A data allocation strategy based on capacity and workload is introduced to achieve local load balance, and a dynamic load adjustment strategy is adopted to maintain global load balance of cluster. Moreover, data integrity is protected by using session reassemble and session partitioning. The simulation results show that the new model enjoys favorable advantages such as good load balance, higher detection rate and detection efficiency.