机械设备性能退化评估与预测研究综述

机械设备性能退化评估技术在提高设备的可靠性和利用率、缩短停机维修时间、实现设备主动维护和智能维护方面有着重要的意义,是故障诊断技术的重要组成部分。综述国内外机械设备性能退化评估与预测的理论和方法,将这些方法分为两类,基于物理模型的方法和基于数据驱动的方法,重点论述基于数据驱动的方法及取得的进展,主要包括基于统计理论方法和人工智能方法等,总结比较每种方法的优缺点,并对机械设备性能退化评估与预测技术的发展方向进行展望。     

信息

2002 年 第 3 期 文 章 介 绍制造工厂技术与制造科学(二)基于Web网络环境分布式制造系统面向Internet的设备智能维护技术利用CPC与VPN技术构建虚拟制造系统特种制造业准时制用户驱动生产系统研究基于XML的企业产品数据服务中心研究制造系统数据采集技术研究金卤灯再启动特性测     

机械加工系统运行状态异常检测方法的研究

智能维护技术对实现机械加工系统的预测维护意义重大,其中,对加工系统性能退化程度进行定量评估是实现预测维护的重要环节,但由于设备故障信息难以获取,使预测维护技术的应用受到一定的限制.为此,本文提出了异常检测的概念和基于统计理论的异常检测方法.通过对加工系统当前状态的异常检测,来对其异常偏离程度进行量化,目的是大幅提高加工系统预测维护的易操作性和应用范围.该方法已在精密曲线磨削主轴系统运行状态的监测中取得了良好的效果,并为系统性能退化程度的在线评估奠定了基础.     

面向智能维护的嵌入式无线预诊断智能体技术

介绍了嵌入式无线预诊断智能体(ETPA)的发展现状，深入分析了设备性能退化评估技术、数据转换、优化和同步技术、无线通讯技术、嵌入式系统与SoC技术几项实现ETPA的关键技术，介绍了D2BTM平台和Watchdog Agent^TM等基础研究成果，提出了利用GPRS实现ETPA无线数据传输的新方式。最后展望了ETPA在不同行业的应用前景。     

数据驱动下的滚动轴承性能退化评估研究综述

随着科学技术的发展、工业技术的不断创新,机械设备越来越重要,机械设备的健康状况也越来越受重视.基于数据驱动理论对国内外滚动轴承的特征提取方法和性能退化评估模型进行综述,分析了各种方法的优缺点,并对滚动轴承性能退化评估技术进行展望.     

基于性能退化的智能脱扣器电源模块健康状态预测

一般情况下电子产品在失效前性能已经发生退化，而传统的寿命预测方法没有利用退化信息。以智能脱扣器电源模块为研究对象，分析MOSFET开关周期和电路薄弱环节储能电容退化之间的关联关系，提出将MOSFET开关周期作为电源模块性能退化的特征量，建立以MOSFET开关周期为特征参量的智能脱扣器电源模块性能退化模型；将电源模块划分为健康、注意和危险3种健康状态，确定健康状态转移图和转移时间的计算方法，建立其健康状态评估模型；对电源模块进行温度应力下的加速退化实验，验证性能退化模型和健康状态评估模型，并预测电源模块在40℃工作环境下由健康状态转移至注意状态的平均转移时间为3 906天，转移至危险状态的平均转移时间为9 296天。     

基于Web的标准信息管理系统

提出了基于Web的B／S结构标准信息管理系统。系统采用三层架构，应用MicFOSOfl公司的ASP（Active Server Page）技术开发，使用ADO（ActiveX Data Objects）技术访问SQL SERVER2000后台数据库，DTHML技术表现用户界面。基于Web的B／S结构系统，无需维护客户端、无访问人数、区域限制，具有广阔的应用范围。     

基于PLC的三轴机械手控制系统的设计与实现

三轴机械手作为智能制造系统中的一个重要组成部分,在工业生产领域得到了广泛的应用。根据三轴机械手运行控制要求,以PLC为核心控制器,应用步进驱动、传感器监测、触摸屏技术,结合气动驱动等多项技术,设计满足准确定位、牢固抓取及移动要求的控制系统。通过对其程序柔性化的设计,可以实现机械手不同运行轨迹的操作,以此驱动现代制造业自动化技术的大力发展。实际运行表明,该控制系统的设计具有很好的实际应用价值。     

三维CAD技术在机械设计中的应用

随着计算机性能的提高，网络通讯的普及化、信息处理的智能化，CAD三维技术正向着开放、集成、智能和标准化的方向发展。本文概述了CAD技术的工作过程中工作环节、步骤和程序以及如何应用在机械的制造业中,预测机械制造业中CAD的发展前途。     

基于深度信念网络多参数智能融合的滑靴副性能退化状态评估方法

滑靴副磨损过程的性能退化状态受到表面形貌、摩擦特性等多个方面的影响,单独提取其中任何一个表征参数作为指标,评估其性能退化状态都是不准确的,为提高评估精度,提出基于深度信念网络多参数智能融合的滑靴副性能退化状态评估方法。应用分形理论从滑靴表面形貌特征中提取分形维数、尺度系数和特征粗糙度等分形参数作为表面形貌评估指标,应用摩擦因数作为摩擦特性参数评估指标,构建性能退化状态评估指标体系;计算摩擦因数信号与完全平稳的高斯白噪声序列信号之间的灰色关联度,并根据灰色关联度的大小对性能退化状态进行区域划分;应用深度信念网络理论对多指标参数进行智能融合和特征提取,建立性能退化状态评估模型;开展滑靴副磨损过程模拟试验,分析指标参数和灰色关联度对性能退化状态的影响规律,通过构建出的样本数据集,对评估模型进行训练和测试验证,结果表明评估模型对性能退化状态的评估准确率能够达到97%以上,由此证实该方法对滑靴副性能退化状态评估的有效性,且具有较高的评估精度。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.