适用于输电线路监测的自供电无线在线监测系统

高空输电线路的实时在线监测对于电网安全可靠运行非常重要,然而输电线路在线监测系统的传统电源供给方式如感应取电、太阳能等方式,难以满足实际应用场景的需求。提出一种基于电磁-压电-摩擦纳米发电机的混合式自供电能量收集方法,将输电线路振动能转换为电能为在线监测系统供电,同时采集输电线路温度、弧垂、微风振动信息,无线发送至终端服务器,实现对电网线路的实时监控预警。系统包括复合能量收集器、电源管理模块、传感监测模块、无线通信模块、数据分析与处理模块等,实现低功耗自供电感知、无线数据收发、电磁屏蔽、数据分析与展示及实时监控预警等多项功能。系统收集环境振动能实现自供电传感,结合无线传输互联网技术形成的无线输电线监测网络实时性强、监测效率高,对提高国家电力系统的稳定性和可靠性具有非常重要的意义。     

斜齿轮振动噪声分析方法

齿轮啮合传动的不平稳是产生振动噪声的主要原因,需要对齿轮啮合传递的动态过程及其规律进行研究。首先,以自动变速器中一对常啮合斜齿轮为研究对象,分别采用有限元法和切片理论计算斜齿轮的传递误差,用以衡量斜齿轮啮合传动的平稳性。然后,根据齿轮修形的经验公式,确定斜齿轮修形参数的范围。基于切片理论,采用列举法,以降低传递误差波动、改善齿面载荷分布为优化目标,确定最优修形方案。最后,通过分析自动变速器的振动噪声台架实验测试结果,有效地验证了笔者采用的方法及模型的可行性。     

一种可视化设计结构矩阵的产品设计模块化识别方法

为识别和划分产品模块化设计中模块的优劣,提出了一种可视化设计结构矩阵方法.通过分析模块的基本特征,提出了模块强度的概念及计算准则.利用设计结构矩阵建模产品内组件间相互关系,运用遗传算法优化矩阵.计算矩阵中所有潜在模块的模块强度,应用不同透明度下的颜色填充技术实现模块识别的可视化,从而为不同需求下的产品模块的识别和划分提供基础.结合数控挽把机的模块识别实例,验证了该方法的有效性和实用性.     

综合传动装置变速机构振动频率与敏感度分析

为了避免综合传动装置在扭转振动时发生共振，需要对传动装置的结构参数进行重新设计、修改。一个复杂的传动装置中，修改哪些结构参数才能有效地改变系统的固有频率是不易确定的。文中建立某综合传动系统的多自由度质量－弹性－阻尼动力学模型，根据复模态振动理论求解该系统在某一挡位下的振动模态，并进行振动频率对系统结构参数的敏感度分析，从33个结构参数中选出4个进行修改，可以有效地改变系统的固有频率。     

基于创成设计思想的可重构机床模块设置方法

建立合理的功能模块群是实现可重构机床方案重构的关键,基于创成设计方法建立了以镗铣加工为主的机床结构形态方案图谱,解决了机床模块划分时机床结构形态方案不足的问题。通过对机床结构形态方案的分析,划分出机床概念结构模块群;依据可重构机床模块功能自治原则,建立了机床概念功能模块群;将机床的概念功能模块、运动功能及被加工零件的工艺方案联系起来,建立了以工艺方案为依据的可重构机床功能模块群设置方法,并以某变速箱壳体件加工为例验证了该方法的可行性。     

面向绿色性能优化的产品族模块再设计优先次序识别

针对产品族绿色化过程中模块再设计优先次序识别问题，基于产品族层次结构模型提出功能模块通用性指标，以反映模块类型对再设计优先次序的影响；构建模块实例生命周期绿色性能评估模型，采用模糊层次分析法和灰色关联分析法来评价模块实例的绿色性能；以绿色性能评价值与通用性指标值之比来确定模块再设计优先次序；通过实例验证了所提方法的可行性和有效性。     

混凝土泵车的产品模块建模方法研究

针对泵车产品设计成本高和开发周期长的问题,采用模块化建模方法建立了泵车模块化产品开发平台。以泵车销轴为例,通过模块几何形状和结构参数分析,建立了销轴模块的主模型、主文档,生成了不同的销轴工程图实例。对泵车一级模块和二级模块的模块接口进行了类别划分。根据产品数据管理系统(PDM)和产品主结构,构建了订单产品模块化设计需要的模块分类树,划分出了泵车的基本模块、必选模块和可选模块,在此基础上进行了产品结构参数系列化设计和产品结构模块系列化设计。泵车模块建模方法在企业的实践结果表明:该方法减少和优化了约30%的零部件品种规格,缩短了近50%的产品研发时间,在降低生产成本的同时还提升了泵车产品的研发质量和品牌竞争力。     

采煤机摇臂齿轮传动系统振源定位分析方法

为了研究采煤机摇臂传动齿轮的振动分析方法并进行实机振源定位验证,首先,采用小波分析对采煤机摇臂振动信号进行降噪处理和频谱分析,依据特征频率下的振幅结果确定故障齿轮的啮合频率;然后,通过Morlet小波包络解调分析获取边频带信号频谱特征,依据边频带特征频率下的振幅结果确定故障齿轮的转动频率;最后,对频谱分析和Morlet小波包络解调分析的结果进行综合分析,锁定故障齿轮的准确位置。对一台国产采煤机摇臂齿轮传动系统进行了振动测试与信号分析,结果表明,基于小波分析、频谱分析和Morlet小波包络解调分析相结合的振动分析方法可以实现对采煤机摇臂故障齿轮的准确定位,为强噪声环境下复杂齿轮传动系统的故障快速定位和现场定点维修提供了方法支持。     

Isomorphism analysis on generalized modules oriented to the distributed parameterized intelligent product platform

The distributed parameterized intelligent product platform (DPIPP) contains many agents of a product minimum approximate autonomous subsystem (generalized module). These distributed agents communicate, coordinate, and cooperate using their knowledge and skills and eventually accomplish the design for mass customization in a loosely coupled environment. In this study, a new method of isomorphism analysis on generalized modules oriented to DPIPP is proposed. First, on the basis of the bill of material partition and generalized module mining, the parameters of the main characteristics are extracted to construct the main characteristic parameter matrix. Second, similarity calculation of generalized modules is realized by improving the clustering using representatives algorithm, and isomorphism model sets are obtained. Generalized modules with a similar structure are combined to complete the isomorphism analysis. The effectiveness of the proposed method is verified by taking high- and medium-pressure valve data as an example.     

IGBT模块空洞率与其温度分布特性关系研究

IGBT模块焊接层空洞会使得模块局部热阻增加、散热能力降低进而导致表面温度场畸变。本文基于红外热像仪和DSP控制单元搭建温度分布检测系统,实现IGBT模块温度场信息的采集、处理和分析。根据实验需要采用自制IGBT模块研究空洞对温度场的影响。通过对不同空洞尺寸的模块进行实验,获得空洞率与温度场分布特性之间的关系。结果表明IGBT模块温度分布特性可以用来进行空洞的定量检测,并给出了根据表面温度特性对IGBT模块性能评估的一般方法。     

基于AMESim的混合动力汽车DHT换挡执行机构的设计与仿真

DHT换挡执行机构帮助混合动力变速器在不同工况下切换不同模式，以提高车辆的动力性能与能源使用效率。以某混合动力变速器为研究对象，设计了一套电控液压换挡执行机构，描述了该机构在混合动力变速器中的位置与功能；根据液压原理图与控制流程图，详细介绍了系统组成与工作原理，并对液压缸的主要参数进行了设计计算；最后，以AMESim软件为平台，对液压系统进行仿真分析，仿真结果表明该液压系统中各元件可按预期稳定工作，验证了设计的合理性。     

Module level fault diagnosis for analog circuits based on system identification and genetic algorithm

This paper proposes a new module level fault diagnosis method for analog circuits. Firstly, the transfer function is constructed according to the relationship between output and input of the circuit under test (CUT). Every system parameter of the transfer function is expressed by several component parameters. These components are divided into several modules. Then, the way of objective function optimization based on genetic algorithm (GA) is adopted to solve nonlinear equations, which are obtained by multi-frequency testing. Finally, the module level faults are detected by comparing the estimated system parameters to their normal values. The results show that the proposed method is effective to identify system parameters and locate module level faults.     

自动变速器换挡冲击故障诊断及排除

汽车电控自动变速器换挡冲击故障的诊断与排除是汽车维修工作中的难点.通过对电控自动变速器换挡冲击故障的实例分析,为自动变速器换挡冲击故障的诊断与检修提供了实践经验.     

Comparison of piezoelectronic networks acting as distributed vibration absorbers

Electric vibration absorbers made of distributed piezoelectric devices for the control of beam vibrations are studied. The absorbers are obtained by interconnecting an array of piezoelectric transducers uniformly distributed on a beam with different modular electric networks. Five different topologies are considered and their damping performance is analysed and compared. Their optimal parameters are found by adopting a criterion for critical damping of k̄-waves: the parameters are suitably chosen to have the quickest temporal vibration decay for a single wave number k̄. The analysis is based on homogenized models of the modular piezo-electromechanical systems, i.e. they are regarded as continuous systems by assuming that the number of modules per unit length is high enough with respect to the considered wave numbers. Calling k̄ -absorbers the corresponding optimal absorbers, we show that: (i) k̄-waves are damped in k̄-absorbers with an optimal decay time which is independent of the absorber interconnecting topology, while it depends only on the piezoelectric coupling coefficient; (ii) the efficiency of k̄-absorbers depends significantly on the absorber interconnecting topology for k different from k̄; (iii) one of the proposed absorbers (which is made of a fourth-order electric transmission line with a second-order electric dissipation) equally performs for all the wave numbers and accomplishes an effective multi-modal damping for the mechanically forced response; (iv) the optimal values of the electric parameters differently depend on the number n of used circuit modules for different interconnecting topologies and, in particular, the optimal inductance per module needed in a fourth-order electric transmission line is proportional 1/n³.     

Vibration transmissibility reduction module with flexure mechanism for personal tools

In many mechanical operations, vibrations from personal tools may cause serious injuries to the human body. This is particularly true in the case of vibrations that are constantly and repeatedly transferred to humans. In fact, a serious physical problem, Raynaud’s phenomenon, may occur. In this paper, we propose a vibration transmissibility reduction module with a flexure mechanism for personal tools. First, a target personal tool, that is, a grass cutter is selected, and the level of vibration transmissibility to the hand is measured. Subsequently, we develop a concept design of the module with stiffness to reduce the vibration transmissibility by more than 20%. The vibration transmissibility is measured by an accelerometer. In addition, the vibration reduction is enhanced when the gap between the inner and outer bodies is filled with silicone gel. Finally, this is verified experimentally.     

Enhanced detection of rolling element bearing fault based on stochastic resonance

Early bearing faults can generate a series of weak impacts. All the influence factors in measurement may degrade the vibration signal. Currently, bearing fault enhanced detection method based on stochastic resonance(SR) is implemented by expensive computation and demands high sampling rate, which requires high quality software and hardware for fault diagnosis. In order to extract bearing characteristic frequencies component, SR normalized scale transform procedures are presented and a circuit module is designed based on parameter-tuning bistable SR. In the simulation test, discrete and analog sinusoidal signals under heavy noise are enhanced by SR normalized scale transform and circuit module respectively. Two bearing fault enhanced detection strategies are proposed. One is realized by pure computation with normalized scale transform for sampled vibration signal, and the other is carried out by designed SR hardware with circuit module for analog vibration signal directly. The first strategy is flexible for discrete signal processing, and the second strategy demands much lower sampling frequency and less computational cost. The application results of the two strategies on bearing inner race fault detection of a test rig show that the local signal to noise ratio of the characteristic components obtained by the proposed methods are enhanced by about 50% compared with the band pass envelope analysis for the bearing with weaker fault. In addition, helicopter transmission bearing fault detection validates the effectiveness of the enhanced detection strategy with hardware. The combination of SR normalized scale transform and circuit module can meet the need of different application fields or conditions, thus providing a practical scheme for enhanced detection of bearing fault.     

基于边界元理论的鼓风机组管路振动噪声控制研究

针对鼓风机组管路振动噪声问题,应用结构声辐射理论和结构振动测量数据分析振动声辐射强度。以实测振动信号为依据,根据对低频段计算精度较好的边界元理论,应用有限元软件和Sysnoise声学仿真软件建立了实际声场的边界元流体模型和有限元结构模型的耦合模型,得到了模拟声场的仿真结果,并与实测结果进行比较,确定了主要噪声能量来源于管路振动造成的结构振动。通过分析振动的来源以及振动传递的路径和传递特性,确定了隔振降噪的方法。依据理论分析结果,对实际现场采取了有效的隔振降噪方法,隔振后降噪效果明显。     

齿轮传动系统结合部动力学参数识别

提出了一种有限元法和实验模态分析相结合用以建立齿轮传动系统的模态坐标模型和物理坐标模型的方法。其中包括齿轮轴的横向弯曲振动,齿轮扭转振动和轴向振动等方向的结合部参数识别。     

齿轮传动系统的动力学与模态分析

为了提高齿轮设计的准确性,结合UG软件参数化建模功能,建立齿轮传动三维实体模型。利用ADAMS软件对齿轮传动系统进行了动力学分析,在高速传动中施加实际传动载荷,得到了齿轮传动系统的振动频率范围和高频率点。通过ANSYS Workbench软件对齿轮传动系统和单一齿轮模型进行模态分析,得到齿轮传动系统和齿轮模型的固有频率和振型,通过与动力学分析得到的频率进行对比,验证了齿轮传动系统的设计准确性,从而为今后齿轮的传动分析提供了数据支持,并为传动过程中的故障分析提供了参考。     

Proposal of a face gear which generates virtual high mesh frequency by addition of grooves on the tooth flank,and the investigation via vibration simulator and actual samples

This report discusses the method of tooth flank modification of a face gear which improves the handle rotational feeling in a fishing reel. A vibration based on a gear pair engagement in fishing reel occurs when a handle of the reel rotates. When this vibration is large, an angler feels uncomfortable, and it is known that the rotational feeling strongly depends on the transmission error of a face gear which is mounted on the reel. In this report, a new method of tooth flank modification was proposed. Based on the new method, it is possible to increase the mesh frequency while keeping the module size and the outer diameter of the face gear unchanged. In this method, several grooves were added along the contact curve on the tooth flank of the face gear. The influence on vibration by these grooves was investigated using the vibration simulator which was introduced in the author’s previous reports. Moreover, sample face gears were manufactured and the rotational feeling was evaluated. As a result, it was confirmed that the rotational feeling was improved by applying a proper number of grooves and groove width.