基于Fluent的静压支承油膜仿真计算研究

以静压支承结构为研爱对象,利用Fluent工具对整个静压支承结构进行了数值仿真,验证了静压支承油膜的形成。仿真分析的结果表明,初始尺寸的静压支承结构压力油膜能够形成,油腔部分压力场基本稳定,油膜部分压力场逐渐减小：油膜部分流速较大,固定阻尼部分流速变化较大;初始油腔的厚度值较大,会在油腔内部形成涡流;最后根据分析结果对结构尺寸作了局部优化。     

梯形均压槽对气浮支承静承载特性的影响研究

为提高气浮支承承载力和刚度,设计了一种梯形均压槽表面节流气浮支承。建立梯形均压槽气浮支承流场的CFD模型,进行数值仿真。研究了梯形均压槽的半径、深度、数目、角度和供气压力对静压气浮支承静态特性的影响规律。结果表明:梯形均压槽可以提高气浮支承的静承载特性;在相同气膜厚度下,气浮支承的承载力随梯形均压槽深度、数目、角度、半径及供气压力的增加而提高;刚度随着均压槽深度、数目、半径及供气压力的增加而增大;刚度峰值所对应的气膜厚度随着均压槽的半径、深度、数目增加而增加。因此,合理设计均压槽可以有效提高气浮支承的静态性能。     

基于PLC的回转支承装配检测台控制系统设计

针对目前回转支承装配和检测中存在的装配质量差、检测强度大等问题,设计了一种基于PLC的回转支承装配检测台控制系统,该系统由装配和检测两部分组成。本文设计了装配检测台的结构和工艺流程,并由此提出了控制系统的控制要求,进而阐述了控制系统的硬件组成和软件设计。结果表明,该控制系统操作方便、自动化程度高,具有一定的工程实用价值。     

回转支承滚道淬火深度的电涡流检测装置

正为提高回转支承的承载能力与使用寿命,需要对其滚道表面进行高频淬火。回转支承属于重型零部件,成本较高,不适宜采用破坏性的切片式金相淬火深度检测方法,只能采用无损检测方法检测其滚道淬火深度。1.三种无损检测方法目前金属材料热处理深度无损检测方法主要有超声波、电涡流、励磁检测残磁量等几种。其中超声波检测人为误差较大,需要检测人员掌握超声波检     

基于机器视觉的玻璃马赛克缺陷在线检测系统

针对玻璃马赛克存在斑点、崩角等常见工艺缺陷,基于机器视觉检测原理,设计了一种采用LED同轴光照明和CCD相机为图像获取工具的在线检测系统。该系统通过相机实时拍摄,获取传送平台上目标玻璃马赛克图像,使用特定的视觉软件对获取到的图像进行中值滤波、锐化、二值化、边缘轮廓提取等图像处理,提取图像中玻璃马赛克轮廓形状与灰度值信息,通过形状匹配与灰度值匹配,实现对玻璃马赛克工艺缺陷的在线检测。实验证明,该在线检测系统具有准确率高、实时性强和速度快等优点。     

异型玻璃外廓检测及磨边加工技术的研究

在仿形原理的基础上,提出了一种异型玻璃外廓尺寸的检测方法,通过旋转运动与直线运动结合,将传感器采集信息进行数据处理和坐标变换后,获得待测异型玻璃外廓的尺寸,为外廓磨边加工的进行提供精确的运动轨迹.在此研究基础上,采用基于PC开放式数控方式,实现对异型玻璃外廓检测和磨边加工运动控制,并结合实际应用,从硬件设计、软件设计两个方面介绍了基于翠欧开放式运动控制器的异型玻璃外廓检测及磨边加工系统,最后进行了试验验证.     

基于卷积神经网络的玻璃瓶口缺陷检测

摘键要：在玻璃瓶的生产中,玻璃瓶制品的质量检测显得尤为重要。随着计算机硬件的更新进步和不同视觉检测算法提出,在工业中机器视觉产品检测逐渐代替人工检测。针对玻璃瓶口的缺陷检测,对玻璃瓶口进行图像采集及预处理,采用预处理的缺陷图作为数据集,利用嵌套残差神经网络的图像识别模型对玻璃瓶口进行缺陷检测并分类。实验结果表明,该方法能够有效提高玻璃瓶口缺陷分类的正确率,验证了该方法的有效性。     

基于ABC-DPC算法的玻璃窑炉能耗异常检测

针对传统的窑炉异常检测方法易受主观因素干扰且存在异常冗余报错的情况,提出一种基于人工蜂群算法的密度峰值聚类(ABC-DPC)的玻璃窑炉能耗异常检测方法。该方法针对密度峰值聚类存在人工设定参数和无法自动划分簇中心和离群点的不足,以人工蜂群算法实现了截断距离的自适应优选过程,并设立离群系数策略以实现自动划分簇中心和离群点的功能。研究了玻璃窑炉的分层能耗模型,并基于此导出能耗特征值,然后应用ABC-DPC算法实现窑炉异常能耗的聚类检测。实验结果表明,所提出算法较于经典聚类算法,检测准确率较高,而且能实时地检测窑炉的能耗异常状况。     

基于多尺度卷积神经网络的玻璃表面缺陷检测方法

卷积神经网络在图像处理中的应用越来越广泛,针对图像处理技术手段在玻璃生产表面缺陷有效检验,分析了基于卷积神经网络的机器学习原理与方法,提出一种基于多尺度卷积神经网络(MCNN)图像识别模型,将MCNN模型在玻璃表面缺陷识别中进行应用实践研究,通过采用不同的算法模型和分类器进行对比实验,并运用混淆矩阵和F1值来评估学习器性能。实验结果表明,所设计的MCNN均比传统卷积神经网络(CNN)识别方法的准确率较高,尤其是在划痕缺陷和杂质缺陷图像的识别准确率上提高了较大的幅度,F1值均提高了5.0%以上,在玻璃缺陷检测的整体识别准确率上较优。     

空间光学遥感器的多光谱TDI CCD信号检测及仿真

为了实现采用高性能多光谱TDI CCD 对空间光学遥感系统的合理设计及应用,提出了对CCD控制信号的高速并行实时检测方法和视频图像连续输出的仿真设计方案。利用CCD行读出及转移的200µs周期,对48路控制CCD驱动信号和31路直流偏置信号进行并行实时逻辑分析及检测。同时,把预制的CCD模拟图像,从磁盘阵列经PCI-X及LVDS总线高速传输到由FPGA、D/A、放大和滤波电路组成的视频图像生成系统,实现可连续、实时输出各种模拟测试图像。实验结果表明,可同时输出3路6MHz频率的彩色图像和8路12MHz频率的全色图像象素信号波形。象素信号基准电压8V;振荡幅值0～1.7V。有效采样时间和信号稳定度均满足成像电路的仿真测试要求。     

基于Fluent的螺旋槽干气密封数值模拟与分析

笔者从计算流体力学出发,使用GAMBIT对模型进行网格划分,用世界著名的CFD软件Fluent对螺旋槽干气密封进行了数值模拟分析,并与权威的试验值进行比较,验证了所用方法在螺旋槽干气密封研究中应用的可行性和可信性。     

反复印压作用下光学玻璃的微裂纹交互作用研究

对超声振动辅助磨削加工中BK7光学玻璃材料表面及亚表面的微裂纹扩展过程中的交互作用进行研究,使用维氏金刚石压头进行了BK7光学玻璃二次印压实验来模拟超声振动作用影响下单颗磨粒对光学玻璃的反复印压作用,同时采用界面粘结法获得了不同印压载荷及印压距离下产生的压痕及微裂纹形态特征及分布情况。实验结果表明：在相同载荷加载情况下,第二次印压产生的亚表面中位裂纹扩展最大深度受到侧向裂纹影响减小了30μm,同时侧向裂纹闭合后在光学玻璃材料表面及内部产生破碎。基于压痕断裂力学理论,分析了准静态载荷作用下光学玻璃内部应力场的分布及应力场驱动下微裂纹的扩展机制,对超声振动效应影响下微裂纹扩展的交互作用进行研究。结果表明：磨削过程中使用轴向超声振动辅助,能够有效地降低光学玻璃材料亚表面裂纹的深度,改善亚表面及表面加工质量,同时促进了工件材料的去除。     

误差对气体静压球轴承静态承载性能的影响分析

针对一种新型闭式结构的小孔节流气体静压球轴承,结合其制造方法,分析了在制造、安装以及工作过程中可能产生的误差,建立了该轴承含误差项的气膜间隙一般表达式,采用Galerkin——有限元方法求解气体润滑雷诺方程,定量分析了各误差对静态承载性能的影响程度。研究结果表明：误差对该结构轴承的静态承载性能的影响与误差的大小及轴承的设计参数取值有关;不同的误差类型对承载性能的影响不同,但均具有一定规律性。得出的结论对于该类轴承的设计制造和性能保障具有重要的指导价值。     

Performance of an externally pressurized rectangular gas bearing under constant effective recess pressure

The present study predicts the performance of an externally pressurized rectangular recessed gas bearing under different operating conditions. The analysis makes use of simplifying assumptions and an empirical formula which relates the recess pressure to the bearing supply pressure. A comparison between the theoretical results obtained and available experimental data shows qualitative agreement. There are some deviations in pressure distribution and load-carrying capacity especially at greater film thickness and supply pressures. The reasons for these deviations are discussed.     

用空间载频法测量玻璃平板的厚度均匀性

设计了一种基于迈克耳逊干涉光路的相位测量系统,将单臂作为检测端完成了对玻璃平板厚度均匀性的直接测量和分析。该系统由CCD采集干涉图样,利用傅里叶变换条纹分析术和相位解包裹技术提取干涉图中所包含的待测相位信息;对于傅里叶变换法中频谱旁瓣中心无法准确定位的问题,采用三角变换法去载频,从而不需要准确地得知频谱旁瓣的中心位置就可以计算出相位结果,消除了人为估算和垂轴方向上的微小载频分量给测量结果带来的误差。实验测量了多块玻璃平板的厚度均匀性。测量结果显示：使用像元大小为4.65 μm×4.65 μm的CCD相机,测量玻璃平板两表面在长度方向和宽度方向上的厚度均匀性的理论精度分别达到0.93%和0.92%,表明本系统基本满足玻璃平板厚度均匀性测量的要求,且对干涉图频谱旁瓣的定位精度和载频的方向精度要求较低。     

In-process estimation of fracture surface morphology during wheel scribing of a glass sheet by high-speed photoelastic observation

Defect-free glass separation techniques are in strong demand in glass processing industries. In this study, we intended to observe the internal stress field during/after wheel scribing of a glass sheet using the photoelastic method. First, we visualized the crack propagation behavior in a 0.7-mm-thick non-alkali glass sheet during mechanical scribing with a 2.0-mm-diameter serrated diamond wheel using high-speed imaging techniques. The observation results under various applied load conditions showed that the crack propagation behavior changed dramatically at a load of approximately 9–10 N; the generated crack hardly propagated in the thickness direction under lower load conditions, in contrast to the rapid propagation under higher load conditions. The fracture surface morphology that was observed after cleavage also changed, from damaged to defect-free surfaces with increments in the applied load around the transition point (9–10 N). This result indicated that the fracture surface morphology was determined by the crack propagation behavior. Second, the birefringence phase difference was measured from the upper side of the glass sheet to enable understanding of the stress fields induced by scribing wheel indentations. As a result, the phase differences that were distributed along the scribe line were shown to differ depending on the applied loads; the phase difference changed little under lower load conditions, but vanished immediately under higher load conditions. Therefore, these differences were dependent on whether or not rapid crack propagation occurred. The measured phase difference distribution thus included information about the crack propagation behavior, and this information could be used as a criterion for estimation of the fracture surface morphology. An in-process estimation method for the fracture surface morphology during mechanical wheel scribing was therefore developed based on high-speed polarization imaging techniques.     

Recursive algorithm for modeling non-linear etching rates in reactive plasma jet based optical surface machining of borosilicate crown glass

Application-specific optical glass properties are achieved by utilizing complex material compositions. This can be problematic in reactive plasma-assisted deterministic surface processing since a non-volatile surface layer may form depending on the glass composition, which affects the etch rate and thereby the local etching depth. In this investigation, a model algorithm is proposed to tackle some restrictions in applying fluorine-based plasma jet as etching tool utilized for freeform surface machining of optics made of complex glass composition, like borosilicate crown glass (e.g., N-BK7®). In this regard, firstly an analytical model is proposed for estimating the depth-dependent etch rate function. Subsequently, a recursive simulation algorithm is introduced for convolving the derived depth-dependent etch rate function with the given dwell time matrix to simulate a deterministic freeform generation process. By the proposed simulation algorithm, the impeding influence of the residual layer on the reduction of etching depth is computed prior to a real experiment in order to scale the local dwell time to ensure the targeted local removal. Finally, the simulated freeform shape is compared with the corresponding result of an etching experiment to validate the feasibility of the proposed approach.     

计入轴倾斜的轴-轴承系统动力学行为研究

以弹性轴的多柔体动力学分析为基础,通过ADAMS与MATLAB联合仿真,解决了计入轴倾斜时弹性轴-轴承系统在正弦和冲击激励力作用下的动力学和摩擦学求解问题.主要结论是:考虑轴倾斜时,轴-轴承系统一阶固有频率略有下降,二阶固有频率略有上升;动力学响应幅度增大.     

Design,fabrication and testing of a compact large-field-of-view infrared compound eye imaging system by precision glass molding

Bionic artificial compound eyes inspire a promising field of miniaturized imaging systems. In this research, a novel infrared (IR) three-dimensional (3D) compound eye imaging system, consisting of a double-side molded 3D microlens array and an aperture array, was designed and fabricated by combining modulated slow-tool-servo diamond turning and precision glass molding. To facilitate the complex profiles on the mold inserts, two novel slow-tool-servo strategies were adopted, namely virtual-axis based diamond broaching and adaptive diamond turning. This microlens array consists of 3 × 3 channels for a field of view of 48° × 48° with a thickness of 1.8 mm. The freeform microlens array on a flat surface was employed to steer and focus the incident light from all three dimensions to a two-dimension (2D) infrared imager. Using raytracing, the profiles of the freeform microlenses of each channel were optimized to obtain the best imaging performance. To avoid crosstalk among adjacent channels, a 3D printed three-dimensional micro aperture array was mounted between the microlens array and the IR imager. The imaging tests of the infrared compound-eye imaging system using the molded chalcogenide glass lenses showed that the asymmetrical freeform lenslets were capable of steering and forming images within the designed field of view. Compared to a conventional infrared camera, this novel microlens array can achieve a considerably larger field-of-view while maintaining low manufacturing cost without sacrificing image quality.     

基于虚拟传感器的气体传感器故障诊断与恢复

对传感器进行故障检测与恢复,对提高系统可靠性是必须的。采用智能软方法可以有效地降低系统的成本。由于化学气体传感器之间具有信息冗余的特点,该文提出了利用神经网络构建虚拟传感器来实现化学气体传感器故障检测与恢复的新方法,该方法已用于一个人工嗅觉系统中,实验表明采用该方法可以方便地实现传感器故障的在线诊断与恢复。