基于模糊控制的雷达红外双传感器有轨电车防撞系统

有轨电车与行人车辆的共享路权使得防撞系统成为行车安全的一个关键环节.采用2套传感器对测量向量异步数据融合并在显示端设置三级声光报警保证障碍检测的可靠性和安全性.在控制器部分,从安全性和舒适性2方面设计了两种模糊控制规则比较输出,保证行车安全的基础上提高了电车制动时的舒适度评价.仿真结果表明:较好地实现了有轨电车的制动要求.     

鞭炮捆筒机热冲击振动消除方法研究与仿真

鞭炮捆筒机在工作过程中,电机到主轴采用皮带传动.火药靠皮带的两侧面与轮槽侧面压紧产生摩擦力进行动力传递的,在摩擦热载荷作用下会诱发机器结构的振动.传统的PID振动控制方法需要大幅调整参数,去满足热载荷作用下的振动控制要求,容易引发参数过量失调,振动控制效果不佳.提出基于模糊自适应PID控制算法的鞭炮捆筒机热冲击振动消除方法.计算V带基准长度,通过运算获取实际中心距离,研究了鞭炮捆筒机带轮振动关系.计算热冲击振动信号与控制参数之间的关联性,并对热冲击振动信号进行离散化处理,对离散化处理结果进行误差补偿,实现热冲击振动消除.实验结果表明,利用改进算法进行鞭炮捆筒机热冲击振动消除,能够有效提高消除的准确性,提高鞭炮捆筒机的应用价值.     

竖向环境振动对人车路系统耦合振动的影响

为分析竖向环境振动对人车路系统耦合振动的影响,人体采用并联动力模型,车辆采用7自由度全车模型,路面采用Kelvin地基上梁单元进行模拟,通过车路之间的动态轮胎力建立起考虑竖向环境振动作用的人车路耦合振动方程；运用New-mark积分法对方程组进行求解,采用人体竖向振动加速度均方根值对车辆乘坐舒适度进行评价；对地震波频率和地震波幅值对系统振动的影响进行讨论,以及车辆乘坐舒适度和乘坐者人体生理反应进行分析.数值分析结果表明：竖向环境振动加剧了人车路系统的振动,显著增大了车辆乘坐舒适度指标；地震波频率和地震波幅值对车辆乘坐舒适度的影响都很大.     

输入滞后结构振动系统的H∞可靠控制

针对一类含有输入时变时滞的结构振动系统,研究了在执行器发生故障情况下系统全局渐近稳定的鲁棒H∞可靠控制设计的问题.首先根据建筑结构力学原理,建立了包含控制输入滞后、执行器故障等的结构系统状态模型.然后基于Lyapunov稳定性理论和线性矩阵不等式处理方法给出了一个时滞依赖型H∞可靠主动控制算法,且控制器存在的充分条件以线性矩阵不等式的形式给出.通过对一个四自由度建筑结构模型在El Centro地震波作用下振动的主动控制仿真,验证了所提方法的可行性,可用于工程结构的振动控制.     

高速车辆结构振动的独立模态空间控制

铁路高速客车或轻型车辆的车体结构振动不仅影响车辆运行品质,而且导致车体结构动应力的增加和疲劳寿命的降低.本文在建立高速车辆的柔刚体系统动力学模型基础上,应用最优控制理论,提出了抑制车体的特定低阶垂直弯曲振动独立模态空间控制方法和已改善车辆运行平稳性为目标的控制策略,分析结果表明:该控制办法和策略可以较好地降低特定模态振动的幅度,改善车辆垂直运行平稳性.     

AT90CAN128的有轨电车检测器设计

本设计以AT90CAN128为控制核心,利用其输入捕捉单元对线圈频率的变化进行检测,使用CAN通信接口将检测结果实时传送,来实现车辆存在与否的可靠检测.本设计将应用于现代有轨电车轨道占用检查子系统中,实现在道岔处对轨道占用的检测,来保障电车的安全行驶和运营调度系统的高效运行.     

多约束非线性结构振动系统的鲁棒H∞容错控制

研究了多约束条件下非线性结构振动系统的鲁棒H∞容错控制问题。根据建筑结构力学原理,建立了包含输入时变时滞、执行器故障、非线性参数摄动以及干扰等多约束条件的结构振动系统状态模型,基于状态反馈和Lyapunov稳定性理论,提出了一个可满足多约束条件的时滞相关鲁棒H∞容错控制算法,该结果以线性矩阵不等式形式给出。在推导过程中只对矩阵不等式进行了两次放大,结果与输入时滞有关,以尽可能降低控制器设计的保守性。该方法设计的控制器能够使得时滞非线性结构振动系统具有指定H∞范数的干扰抑制能力,对执行器故障具有容错性。通过对一个四自由度建筑结构模型在 EI Centro 地震波作用下振动的控制仿真,验证了所提方法的可行性和有效性。     

双磁悬浮振子结构地铁轨道监测小波分析

为实现地铁机车的振动测量设计了双磁悬浮振子结构地铁机车振动测量系统,通过实测和最小二乘函数拟合方法获得振子所受磁斥力与位移的函数关系,分别推导了两个磁悬浮振子的振动方程,建立了双磁悬浮振动测量系统仿真模型。分析表明双磁悬浮振子的灵敏度高于单磁悬浮振子,实测了地铁在匀速运行无振动、匀速运行有振动的波形,并在地铁站台测量了机车进站对站台造成的振动,采用多尺度一维小波分解函数对振动信号进行了分析,得到不同情况下的振动特征,最后对振动波形进行了重构。实测表明,设计的双磁悬浮振子结构地铁机车振动测量系统的可实现机车振动测量,对于地铁轨道故障检测具有一定的参考价值。     

支承舱减振性能分析

支承舱是运载火箭与航天器之间的重要连接结构,支承舱的振动特性是力学环境设计需要考虑的因素之一.本文从振动环境控制的角度进行支承舱结构动力学分析,阐述了一种基于支承舱振动特性研究的改善航天器力学环境的方法.在有限元建模过程中,引入了材料级性能试验.计算并比较了不同材料支承舱结构对航天器振动环境的作用,比较了连接面形式对振动环境的影响.基于分析结果给出了进一步研究的建议.     

振动监控系统在鼓风机系统控制中的应用

我厂引进的闪速焙烧炉中,鼓风机系统是一套关键设备,它提供生产运行必需的燃烧风和输送风。鼓风机如果停转,整套生产设备即联锁停止运行;在鼓风机系统联锁控制中,根据生产运行时的振动实时数据及趋势图,分析鼓风机系统的运行状况,振动高高限信号联锁停鼓风机系统,便于故障诊断和处理。１振动监控系统的工作原理和技术参数 振动监控系统包括ＶＳ－０６８振动速度传感器和ＣＶ－１１０监控器。ＶＳ－０６８是绝对式磁电传感器,其结构是一个位移传感器。根据电磁感应定律,当线圈在磁场中交变运动（设备运转时产生振动）时,所感生的…     

Response of the seated human body to whole-body vertical vibration: discomfort caused by sinusoidal vibration

Frequency weightings for predicting vibration discomfort assume the same frequency-dependence at all magnitudes of vibration, whereas biodynamic studies show that the frequency-dependence of the human body depends on the magnitude of vibration. This study investigated how the frequency-dependence of vibration discomfort depends on the acceleration and the force at the subject–seat interface. Using magnitude estimation, 20 males and 20 females judged their discomfort caused by sinusoidal vertical acceleration at 13 frequencies (1–16 Hz) at magnitudes from 0.1 to 4.0 ms^? 2 r.m.s. The frequency-dependence of their equivalent comfort contours depended on the magnitude of vibration, but was less dependent on the magnitude of dynamic force than the magnitude of acceleration, consistent with the biodynamic non-linearity of the body causing some of the magnitude-dependence of equivalent comfort contours. There were significant associations between the biodynamic responses and subjective responses at all frequencies in the range 1–16 Hz.

Practitioner Summary: Vertical seat vibration causes discomfort in many forms of transport. This study provides the frequency-dependence of vibration discomfort over a range of vibration magnitudes and shows how the frequency weightings in the current standards can be improved.     

一种宽频的磁式压电振动能量采集器

基于环境能量采集的压电振动能量采集器为无线传感器和微机电系统的长期供能提供了一种有效解决方案.目前研制的压电式振动能量采集器存在工作频率高,且频带窄的问题.给出了一种通过磁力的引入使其在低频下工作的、宽频的压电振动能量采集器,并搭建了测试系统对器件进行分析测试.在压电悬臂梁上放置永磁铁取代传统的质量块,同时在悬臂梁的上...     

An analytical investigation of an energy flow divider to attenuate hand-transmitted vibration

A five-degrees-of-freedom (DOF) bio-mechanical model of the hand-arm system is developed to study the vibration transmissibility characteristics of the human hand-arm. The model parameters are identified from the characteristics of vibration transmitted to the hand, forearm and upper arm, measured in the 10–200 Hz frequency range under a constant 25.0 N grip force. A concept of an energy flow divider is proposed to reduce the flow of vibration energy into the hand. The coupled hand-arm-divider is modeled as a six-DOF dynamical system and the response characteristics are evaluated for handle excitations caused by a palm-grip orbital sander. The response characteristics of the coupled hand-arm-divider model are compared to those of the hand-arm model to demonstrate the potential performance benefits of the proposed energy flow divider. The hand-transmitted vibration is further assessed using the overall weighted acceleration response, and it is concluded that the proposed energy flow divider can reduce the magnitude of hand-transmitted vibration considerably.     

建筑结构振动监测和模态识别集成软件

为开发用于建筑结构振动监测与模态识别的集成软件系统,分析监测工作和识别计算的主要工作内容,设计集成软件的架构体系和专业功能,划分出基于Internet的远程监测客户端、结构计算、模态识别和结果对比/评估等4个主要功能模块.根据频域峰值法和时域随机子空间法等识别理论,设计基于实测振动加速度的模态识别数值算法.在Microsoft Windows平台上用C++和FORTRAN程序语言开发该软件包,并用数值测试算例验证软件的正确性.该软件已经应用于"上海中心"大厦在施工过程中的振动监测和模态识别.     

Subjective discomfort caused by vertical whole-body vibration in the frequency range 2–100 Hz

Current standards assume the same frequency weightings for discomfort at all magnitudes of vibration, whereas biodynamic and psychological studies show that the frequency-dependence of objective and subjective responses of the human body depends on the magnitude of vibration. This study investigated the discomfort of seated human body caused by vertical whole-body vibration over the frequency range 2–100?Hz at relatively high magnitudes from 1.0 to 2.5?ms^?2 r.m.s. Twenty-eight subjects (15 males and 13 females) judged the discomfort using the absolute magnitude estimation method. The rate of growth of discomfort with increasing vibration magnitude was highly dependent on the frequency, so the shapes of the equivalent comfort contours depended on the magnitude of vibration and no single frequency weighting would be appropriate for all magnitudes. The equivalent comfort contours indicated that the standards and previous relevant studies underestimated the vibration discomfort at frequencies greater than about 30?Hz.

Practitioner Summary: The discomfort caused by vertical vibration at relatively high frequencies can be severe, particularly at relatively great magnitudes in transport. This study provides the frequency-dependence of vibration discomfort at 2–100?Hz, and shows how the frequency weightings in the current standards can be improved at relatively high frequencies.     

Power hand tool vibration effects on grip exertions

Operation of vibrating power hand tools can result in excessive grip force, which may increase the risk of cumulative trauma disorders in the upper extremities. An experiment was performed to study grip force exerted by 14 subjects operating a simulated hand tool vibrating at 9.8 m/s² and 49 m/s² acceleration magnitudes, at 40 Hz and 160 Hz frequencies, with vibration delivered in three orthogonal directions, and with 1.5kg and 3.0kg load weights. Average grip force increased from 25.3 N without vibration to 32.1 N (27%) for vibration at 40 Hz, and to 27.1N (7%) for vibration at 160 Hz. Average grip force also increased from 27.4 N at 9.8 m/s² acceleration to 31.8 N (16%) at 49m/s². Significant interactions between acceleration x frequency, and frequency x direction were also found. The largest average grip force increase was from 25.3N without vibration to 35.8N (42%) for 40 Hz and 49 m/s² vibration. The magnitude of this increase was of the same order as for a two-fold increase in load weight, where average grip force increased from 22.5N to 35.0N (56%). A second experiment studied hand flexor and extensor muscle responses using electromyography for five subjects holding a handle vibrating at 8 m/s² using ISO weighted acceleration, with frequencies of 20 Hz, 40 Hz, 80 Hz and 160 Hz, and grip forces of 5%, 10% and 15% of maximum voluntary contraction. Muscle responses were greatest at frequencies where grip force was affected, indicating that the tonic vibration reflex was the likely cause of increased grip exertions.     

Bedside safety rails: assessment of strength requirements and the appropriateness of current designs

This second paper in a series of studies of the discomfort produced by multi-axis vibration is concerned with rotational seat vibration. The effects of level, frequency and direction of the roll, pitch and yaw vibration of a firm flat seat have been studied in two experiments. At octave centre frequencies in the range 1-31.5 Hz the first experiment determined the levels of roll, pitch and yaw seat vibration which caused discomfort equivalent to 0-5 and l.25m/s²r.m.s. 10 Hz vertical seat vibration. In the second experiment, comfort contours equivalent to 0.8 m/s² r.m.s. 10 Hz vertical seat vibration were determined from 18 males and 18 females at preferred third-octave centre frequencies from 1 to 31.5 Hz. In all cases the axis of rotation passed through the centre of the seat surface. There was no vibration of the feet and no backrest.

It was concluded that the shape of equivalent comfort contours need not normally depend on vibration, level. Both individual and group equivalent comfort contours are presented. Although there were significant correlations between subject size and subject relative discomfort it is not thought that these correlations have much practical application. In all three axes the median contours of vibration acceleration increase in proportion to vibration frequency. Sensitivity is greatest for roll vibration and least for yaw vibration of the seat.     

The effects of vibration frequency and direction on the location of areas of discomfort caused by whole-body vibration

Although much research has been devoted to the determination of equivalent comfort contours for human response to whole-body vibration little consideration has been given to the source of the feelings that give rise to such comfort contours. This paper shows that for vertical vibration there is a distinct difference in the locations of discomfort on the body at different frequencies and that the locations are not much affected by the vibration level. For horizontal motions, feelings of discomfort predominated in the lower abdomen and buttocks irrespective of vibration frequency or direction. A semantic scaling technique indicates the maximum sensitivity to vertical vibration acceleration in the 4 to 16 Hz range, but for both fore-and aft and lateral vibration there is a decrease in sensitivity with increasing frequency above 2Hz.     

Frequency-dependence of discomfort caused by vibration and mechanical shocks

The frequency content of a mechanical shock is not confined to its fundamental frequency, so it was hypothesised that the frequency-dependence of discomfort caused by shocks with defined fundamental frequencies will differ from the frequency-dependence of sinusoidal vibration. Subjects experienced vertical vibration and vertical shocks with fundamental frequencies from 0.5 to 16 Hz and magnitudes from ±0.7 to ±9.5 ms^–2. The rate of growth of discomfort with increasing magnitude of motion decreased with increasing frequency of both motions, so the frequency-dependence of discomfort varied with the magnitudes of both motions and no single frequency weighting will be ideal for all magnitudes. At the frequencies of sinusoidal vibration producing greatest discomfort (4–16 Hz), shocks produced less discomfort than vibration with same peak acceleration or unweighted vibration dose value. Frequency-weighted vibration dose values provided the best predictions of the discomfort caused by different frequencies and magnitudes of vibration and shock.

Practitioner Summary: Human responses to vibration and shock vary according to the frequency content of the motion. The ideal frequency weighting depends on the magnitude of the motion. Standardised frequency-weighted vibration dose values estimate discomfort caused by vibration and shock but for motions containing very low frequencies the filtering is not optimum.     

铁路车轮导纳分析

为控制铁路车轮的振动和噪声辐射,采用模态叠加法分析车轮频率响应,利用ANSYS建立车轮结构有限元模型,根据0～10 000 Hz的模态计算0～5 000 Hz内的频率响应,用Block Lanzos法计算50～5 000 Hz内车轮的固有频率和振型,分析车轮的固有模态和导纳特性.研究结果表明：车轮在名义接触点处受到不同方向激励时所得的导纳特性与车轮相应的模态有关;对于车轮不同接触点处的激励,在1 000 Hz以下频段,轮缘轴向激励引起的径向导纳大于踏面径向激励引起的径向导纳,在其他频段,踏面径向激励引起的径向导纳都比轮缘激励引起的径向导纳大.铁路车轮导纳分析有助于探明车轮噪声产生的机理,是轮轨噪声分析的基础.