光电平台无角位移减振装置设计研究

光电平台是一种利用光电载荷实现目标探测与监视的光电系统,为了获得高质量的图像,设计了一套减振装置来减小振动对成像质量的影响,尤其是减小对图像质量影响较大的角振动.根据空间机构学原理和减振理论,尝试通过空间连杆机构来实现无角位移振动,分析了无角位移减振装置的减振机理,建立了无角位移减振装置仿真模型,计算了不同激励下无角位移减振装置的响应,并与目前普遍采用的隔振方案的角振动隔振效果进行了对比,角振动的隔振效果提高了2个数量级,实现了无角位移振动.分析结果显示无角位移减振装置原理正确,设计合理,能够满足无角位移振动的使用要求.     

负泊松比超材料减振结构设计与实验验证

旋转机械的转子部件发生故障时,振幅会迅速增大甚至发散,此时需要一种轻质高效的吸能减振结构,快速控制转子部件的振动幅值.本文基于负泊松比材料概念,提出了一种针对转子系统的负泊松比弧形超材料减振结构,可以实现很好的故障转子减振效果.首先,通过释放自由度提出了负泊松比非对称星形胞单元,设计了针对转子的超材料减振结构,并给出了相应的能量吸收指标.然后,基于有限元模型进行了动力学仿真,讨论了不同冲击速度、不同冲击角度对能量吸收性能的影响.结果表明,低速冲击下,材料主要产生弹性变形吸能.随着冲击速度增加,材料变为弹塑性变形混合吸能模式,有效吸能率会明显增大.特别是在冲击速度较大时,减振结构的吸能率会迅速增加,这对于转子突发故障的减振十分有利.最后,设计了验证实验,对故障转子进行了负泊松比减振结构的验证实验.实验结果证明,对于转子的不平衡故障响应,设计的减振结构能够起到很好的抑制转子振动与吸收振动动能效果.     

基于CPLD高速信号存储测试系统的设计

针对减振控制装置中高频振动信号的采集问题.本文设计了一种基于CPLD为核心控制电路的高速数据采集系统.该信号采集过程是由硬件电路控制,并实时将转换数据存储起来,信号转换后进而由计算机处理采集到的数据.实验结果表明,该电路能够准确有效地进行AID数据采集.     

一种主动振动控制测试装置

为顺应智能制造中测试平台的发展趋势,本文研究设计了一种新的主动振动测试装置。该装置基于LabView测试软件,通过RT模块实现控制器之间的数据传递,并建立了上位机和下位机之间的实时通信。与传统的主动振动测试平台相比,该装置既能主动减振又能降低成本,操作简单且具有高效性。     

舰船概念设计中振动预报方法

以带有双层隔振装置的舰船模型为对象,利用MSC Nastran的有限元分析方法以及试验手段,对其隔振性能进行研究.将船体与双层隔振装置作为一个系统,建立三维有限元振动分析模型;以降低船体结构振动能量为目标,对发动机激励作用下的双层隔振装置与船体的振动特性进行分析;通过有限元分析方法和试验两方面的研究与对比,为舰船的减振降噪的初期概念设计提供快速预报方法.     

仿人机器人单双脚支撑转换时的消振研究

单双脚支撑转换时的冲击振动是一个影响仿人机器人稳定行走的重要因素.本文从振动方程的特性和系统的稳定性分析减振的设想和措施,并运用基于ANSYS平台所建立的THBIP-Ⅰ型仿人机器人精确的有限元弹性动力学模型,进行仿真分析比较,并加以实验验证.结果说明有限元分析法是研究仿人机器人缓冲减振的一种有效途径,所获得的结论能够为实现高品质的快速步行及控制规律做出有效的指导.     

倾斜安装电机振动特性研究

因为安装空间和实际运行的需要,电机在倾斜工作状态下容易产生振动超标。该文针对倾斜安装异步电机结构特点,设计了倾斜安装异步电机的振动特性实验装置,分析了含有减振垫的异步电 机系统刚度特性,通过有限元分析计算出了不同厚度减振垫的刚度系数。实验中,采用不同厚度橡胶减振垫进行振动测试分析,结果显示,在倾斜 5°的安装条件下,异步电机共振转速随减振垫刚度的减小而明显减小。该研究结果可为倾斜安装电机与减振器振动特性匹配、设计与安装提供理论参考。     

一种直升机旋翼振动测试方法及实验

为了精确测量直升机旋翼振动特性,设计了一种基于加速度计的直升机旋翼振动测试装置.该装置主要包括加速度传感器、A/D转换模块、无线模块、软件处理等部分.通过无线装置将加速度计采集到的振动信号发送到电脑端,进行数据采集和处理.还进行了标定实验和转台模拟实验,得到了需要的振动特性(振幅、振动频率).测试结果表明,设计符合振动测试要求.     

中立型时滞反馈扭转控制系统的稳定性分析

研究了中立型时滞动力吸振器抑制扭转系统的振动问题.针对一类强迫扭转振动系统,采用动力系统的稳定性理论分析了动力吸振器与扭转振动系统的稳定性问题,以时滞为参数,分别得到了动力吸振器与扭转振动系统的稳定区域,并研究时滞变化时动力吸振器对于主振动系统振动的吸收效果,通过与时滞动力吸振器对比,得到了更大的吸振器和减振系统时滞稳定工作区域,通过数值模拟验证了结论的正确性.     

周期性冲击载荷作用下井字梁楼盖竖向振动的控制

针对周期性冲击载荷作用下井字梁楼盖异常振动问题,对某工业厂房井字梁楼盖进行现场动力特性测试,采用Abaqus软件建立局部楼盖有限元模型,研究周期性冲击载荷作用下井字梁楼盖的动力特性,并提出设置调谐质量阻尼器(tuned mass damper,TMD)、增设隔振支座等2种减振方案.结果 表明:4种不同TMD布置方式的减振效果不同,在设备4个支座处布置TMD的减振效果最佳;增设隔振支座后,采用有限元法得到各测点减振率为83.91％ ～88.80％.2种方案均能有效降低楼盖的竖向振动,可为结构振动控制提供参考.     

Recognizing the viscoelastic safe area of work shoe sole in the sitting posture with vibration transmissibility in the vertical direction

Work shoe soles are a useful tool for decreasing the amplitude of vibration transmissibility to the human body for subjects exposed to foot-transmitted vibration (FTV) in the workplace. The main objective of this paper is to identify the viscoelastic safe area of work shoe soles in the sitting posture using a biomechanical model. To identify the model parameters, twelve young males participated in the experimental test. Moreover, to identify the viscoelastic parameters of the shoe sole model, three different work shoe soles, i.e., soft sole (Shore scale: A25), fairly soft sole (Shore scale: A42), and hard sole (Shore scale: A70), were used, whose mechanical parameters were extracted by establishing the experimental test based on vibration transmissibility. Afterward, the viscoelastic safe area of work shoe soles was determined based on vibration power absorption (VPA) for subjects exposed to vibration. The numerical simulation demonstrates that the soft shoe soles can decrease the maximum value of VPA up to two times compared to barefoot conditions. Furthermore, the maximum value of VPA in the hard sole is up to 14% more than that of the soft sole. Furthermore, the experimental test shows that the amplitude of vibration transmissibility to the hard sole is 15% more than that of the soft sole (p < 0.01), which is in line with the results of the numerical simulation. Moreover, increasing the mass of the shoe sole from 0.3 to 0.6 kg leads to a reduction in the viscoelastic appropriate area of the work shoe sole up to nine times.     

Comparative studies of perceived vibration strength for commercial mobile phones

A mobile phone, also known as cell phone or hand phone, is among the most popular electrical devices used by people all over the world. The present study examines the vibration perception of mobile phones by co-relating the relevant design parameters such as excitation frequency, and size and mass of mobile phones to the vibration perception survey by volunteers. Five popular commercially available mobile phone models were tested. The main findings for the perception surveys were that higher vibration frequency and amplitude of the peak acceleration would result in stronger vibration perception of the mobile phones. A larger contact surface area with the palms and figures, higher peak acceleration and the associated larger peak inertia force may be the main factors for the relatively higher vibration perception. The future design for the vibration alert of the mobile phones is likely to follow this trend.     

The effect of vibration on the skeleton, joints and muscles. A review of the literature

Owing to the elasticity and plasticity of the skeleton, joints and muscles, the musculoskeletal system is capable of absorbing and damping mechanical vibration without damage as long as the vibration level is within tolerable limits. However, technical developments have led to the exposure of many people to intolerable variation levels with destructive changes as a result.

These injuries to the musculoskeletal system continue to be the subject of research interest. Initially, the joints and joint complaints attracted the greatest attention. Vibration damping takes place mainly in the joints. The incidence of destructive joint changes has been examined in comprehensive clinical, epidemiological and radiographic studies, mainly concentrating on the joints of the hand and arm. The response of muscles to vibration is often expressed in the form of a tonic vibration reflex (TVR) which arises as a result of stimulation of the muscle spindles and therefore resembles the classic tonic stretch reflex. There is increased muscular activation for stabilisation of the joint positions, especially during whole-body vibration. Studies have also disclosed how vibration affects body equilibrium and equilibrium control and how vibration can elicit muscle pain, cramps and reduced muscular strength.     

加权滤波在电梯振动测量中的应用研究

电梯运行振动可以反映电梯整体性能状况。介绍一种加权滤波测量方法，根据人体对不同频率振动的敏感程度，对电梯运行振动数据采用加权滤波方法衡量。该方法在广州东部地区乘客电梯实际测量中得到验证，取得良好效果。     

一个结构振动仿真系统的实现

本文介绍的结构振动的数值和图形仿真系统是我们所研究的振动控制仿真系统的一个模块。介绍了振动的仿真的基本方法和实现过程中的几个关键问题，并概略介绍了作者在微机上实现的仿真系统（ＳＤＳＳ）的主要功能。     

A comparison of vibrotactile thresholds on the finger obtained with different equipment

Vibrotactile thresholds on the finger have been compared using two alternative systems. One system prescribed the push force, the contact force, and the surround, while this was not defined for the other system. The experiment was performed with nine male subjects attending on three different days. It was found that the two systems yielded vibrotactile thresholds which were significantly different. The dependence of vibrotactile thresholds on the frequency of vibration, the area of contact with vibration, the conditions surrounding the contact area, the contact force, the push force, the finger temperature, and the distortion of waveform must be considered when quantifying vibrotactile thresholds.     

Technical Note Human hand-transmitted vibration measurements on pedestrian controlled tractor operators by a laser scanning vibrometer

A first application of a new measurement technique to detect vibration transmitted to the human body in working conditions is presented. The technique is based on the use of a laser scanning vibrometer. It was previously developed, analysed and tested using laboratory test benches with electrodynamical exciters, and comparisons with traditional measurement techniques based on accelerometers were made. First, results of tests performed using a real machine generating vibration are illustrated. The machine used is a pedestrian-controlled tractor working in a fixed position. Reference measurements by using the accelerometer have been simultaneously performed while scanning the hand surface by the laser-based measurement system. Results achieved by means of both measurement techniques have been processed, analysed, compared and used to calculate transmissibility maps of the hands of three subjects.     

一种调节阀减振降噪方法的探索

流体诱发问振动是常见的现象。根据流体诱发阀振动及频率的随机性,用概率论指导研制的“异径多束流调节阀”,在几种工况下,经多年的运行表明,新阀有效地解决了原使用传统调节阀时未能避免的振动,并且其工作特性优良,而所需成本仅为进口低噪音阀的1／8左右。这对解决流体诱发调节间的振动与噪音具有理论和实际价值。     

基于虚拟仪器的旋转设备振动监测与分析系统设计

针对旋转设备振动监测的改造升级项目的用户需求,采用虚拟仪器技术,设计开发了一种分布式的振动监测与分析系统,可对多个设备进行监测并提供多种振动分析图形。系统保留了原有监视仪表的使用,从其BUFFER口或串口采集振动信号,降低了改造费用,实现了平稳升级。LabWindows/CVI软件开发平台的使用,使显示界面和仪表相类似,便于操作人员使用,还大大缩短了开发周期。本文论述了该系统的总体结构和软件功能开发,系统已在工业现场进行了初步测试,效果良好,具有实用价值。     

Vibration of portable orbital sanders and its impact on the development of work-related musculoskeletal disorders in the furniture industry

The wood furniture industry has a strong presence in Canada, where it employs over 100,000 workers. Because of the extensive number of manual tasks required in this industry, several studies have been undertaken to characterize the health and safety risk factors to which these workers are exposed, such as awkward postures, repetitive movements and the application of undue force. However, very little research has been done on workers’ exposure to vibration from portable orbital sanders, one of the most common tools used in this industry. Vibration is responsible for a specific occupational disease called vibration syndrome, but is also recognized as a risk factor that increases the prevalence of more common work-related musculoskeletal disorders (WMSDs). This study proposed to determine the level of vibration to which sanders of furniture parts are exposed, and to analyze its impact on the risk of WMSDs. The results show that the level of vibration to which the workers are exposed is well above acceptable levels defined by recognized standards and directives and that this vibration is combined with many other risk factors, thus representing a risk for the development of WMSDs.