轮对几何参数在线检测系统研究

轮对作为铁路车辆重要的走行部件,对于铁路的安全运输起着关键性的作用。因此准确的检测车轮的磨耗状况是非常重要的。本文将结构光视觉传感技术应用到车辆轮对几何参数的在线测量上,完成测量系统的开发,实现在线动态测量。     

Study of microcontact printed patterns by chemical force microscopy

Patterned self-assembled monolayers (SAMs) on sputtered gold films prepared by microcontact printing (microCP) were studied by mapping adhesive forces with pulsed-force-mode atomic force microscopy. A stamp for microCP was fabricated by pouring polydimethylsiloxane (PDMS) over a photolithographically prepared master. The patterned SAMs were prepared by two methods. One is called the wet-inking method, in which inking was done by placing a thiol ethanol solution for 30 s on the stamp and then removing the excess ink solution under a stream of nitrogen. The other is called the contact-inking method, in which a pad made of PDMS was dipped overnight in a thiol ethanol solution and then the stamp was placed on the inker pad impregnated with the thiol ethanol solution. The second step for pattern formation was the same for both of the two different microCP methods. Namely, the gold surfaces stamped with alkanethiols were further reacted with a thiol terminating in COOH in ethanol. The resulting patterns with CH3- and COOH-terminated regions were analyzed by imaging the adhesive forces with the chemically modified gold coated AFM tips with a SAM of CH3 or COOH terminal functional groups.     

Extraction/conversion of geometric dimensions and tolerances for machining features

It is important for a feature-based system to preserve feature integrity during feature operation, especially when feature interaction occurs. The paper presents a feature conversion approach to convert design features used in a design model into machining features for the downstream applications. This process includes both form features (geometric information) and non-geometric features conversion. Most researchers have concentrated on geometric information extraction and conversion without tackling the important problem of non-geometric feature information. This paper focuses on the extraction and conversion of feature geometric dimensions and tolerances (GD&T) for downstream machining application.The main barrier to the integration of a feature-based CAD/CAPP/CAM system – feature interaction – is discussed in this paper, which alters design features in their geometries and non-geometric information. How to identify and validate these feature dimensions and tolerances is one of the key issues in feature interaction conversion. The development of robust methodologies for preserving feature integrity for use in process planning application is the main thrust of the work reported in this paper.     

精密测角法的线阵CCD相机几何 参数实验室标定方法

建立了线阵CCD相机几何参数标定系统,对该标定方案所用的设备、实验条件、基于精密测角法的算法和精度进行研究。根据标定精度要求,确定了实验室主要测试设备和环境条件。利用高精度二维转台和CCD细分技术测得被标定系统的一系列视场角和对应像高。最后,利用建立的数学模型,应用最小二乘回归的方法,求得相机几何参数。误差分析结果表明:该方法对主距主点的标定精度可以达到μm级,相对畸变的标定精度可以优于1×10^-4。该方法可以满足线阵相机的高精度几何标定要求,具有较高的实际应用价值。     

滚动直线导轨副接触状态及几何尺寸精度设计

以具有节距偏差的四方向等载荷双圆弧沟槽滚动直线导轨副为研究对象，通过装配后的接触状态的几何关系分析推导了节距偏差、间隙量、接触角及二次接触角的计算公式，并进行数值计算及分析比较。所得出的有关沟槽半径公差、节距公差及粗糙等参数的设计方法，对提高滚动直线导轨副的制造精度，保证四方向等载荷的特性，具有指导意义。     

车削刀具几何参数低碳优化建模与求解

为了实现车削加工过程的低碳化并提高加工质量,在分析车削加工过程中能耗特征及切削温度与刀具几何参数之间关系的基础上,以刀具前角和主偏角为优化变量,考虑加工过程机床设备和加工质量等约束,建立了车削加工刀具几何参数低碳优化模型;针对所建模型,提出一种基于改进的自适应遗传算法的优化求解方法。实例分析表明,以低碳排放为优化目标、以切削温度为约束条件优化车削刀具几何参数,可使碳排放和切削温度比原刀具参数分别降低12%和17%。所建模型和方法可为制造企业优化选择刀具几何参数降低碳排放提供理论方法支持。     

Laser sintering of Cu nanoparticles on PET polymer substrate for printed electronics at different wavelengths and process conditions

Frontiers of Mechanical Engineering - This study explores the feasibility of different laser systems to sinter screen-printed lines from nonconductive copper nanoparticles (Cu NPs) on polyethylene...     

Web Tension regulation of multispan roll-to-roll system using integrated active dancer and load cells for printed electronics applications

The mass production of primed electronics can be achieved by roll-to-roll（R2R） printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output（MISO） regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ± 1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.     

复杂零件参数的图像测量方法

提出一种可以用于齿轮等形状复杂零件的二维曲面轮廓测量的图像测量系统。该系统采用CCD摄像机作为传感单元。提出一种基于多项式插值的亚像素边缘检测算法,以提高系统的测量精度。这种算法可以大幅度提高图像测量系统CCD的分辨率,并具有较好的稳定性和较高的运算速度。     

椭圆齿轮几何参数计算及齿形仿真

以渐开线圆柱齿轮为基础,推导出椭圆齿轮压力角、节曲线长度、长/短轴半径和不产生根切的最少齿数等几何参数的计算公式;在AutoCAD环境下,模拟范成法加工齿轮,绘制出椭圆齿轮的齿廓仿真曲线.     

生物反应器系统参数虚拟测试仪的研制

文中简要介绍了生物工程的重要性和生物反应器监控发展概况,以及虚拟仪器在这方面的应用现状和优势。所研制的虚拟仪器可在线检测温度、罐压、溶解氧、pH值、尾气CO2含量等9个参数,充分发挥了虚拟仪器的优势,避免了传统硬件式仪器的不足。着重阐述了生物反应器参数虚拟测试仪的基本结构,在此基础上论述了该虚拟仪器的软件设计和硬件结构,并以温度、pH值为例介绍了它们的检测调理电路。     

通用零件几何参数图像检测系统设计

为实现通用零件几何参数图像检测,采用光学镜头、工业数字摄像机和微型计算机构成基本检测系统,包括测试准备、测试系统调整、图像获取、预处理、边界确定、参数求取和系统标定等检测工作环节.阐述各检测环节的作用和应用中的关键问题、检测应用软件设计.通过所构建的检测系统,对典型零件进行对比测试表明,给出的通用零件几何参数图像检测系统是实用的.     

圆度仪的调平和圆柱度误差评定

从圆柱度误差的测量要求和圆柱度误差评定搜索算法两个方面研究了提高测量精度的方法。为了减小圆柱度误差测量中的工件倾斜误差,设计并分析了两点垂直布局的调平方法;根据工件轴线的方向余弦,计算得到了两点调整的高度值,克服了手动调整存在的问题,实现了工件快速精确调平并提高了工件圆柱度的测量精度。由于圆柱度误差评定是对满足最小条件的圆柱轴线的搜索,文中针对Nelder-Mead单纯形法的收敛精度依赖于初始解和收敛速度较慢,提出了拟牛顿法和Nelder-Mead单纯形法相结合的联合算法来实现全局最优解的快速准确搜索。对经典测试函数的Matlab仿真及实际测量数据的应用表明,该联合算法能有效地提高收敛速度和收敛精度,其收敛速度提高了50%,收敛精度提高了1倍,从而提高了工件圆柱度误差的测量精度。     

天线罩几何参数自动测量系统中的数据采集与处理

在 Win95下开发控制软件,需要一种全新的数据采集与处理方法。介绍了在导弹天线罩几何参数自动测量系统中如何实现实时数据采集,并给出了廓形误差评定等数据综合处理的方法。     

双滚轮-导轨式渐开线测量仪的空间几何误差补偿方法

为解决1级齿轮渐开线样板的精密测量难题,提出了一种基于双滚轮-导轨式渐开线测量仪的空间几何误差补偿新方法.首先,建立了空间几何误差与渐开线齿廓偏差之间映射关系的数学模型;然后,基于该模型对齿轮渐开线样板、基圆盘与芯轴的综合安装误差和基圆盘的圆度误差进行了具体分析;最后,通过改变渐开线展开长度对应的基圆盘使用圆弧段、综合...     

Turbidimetric method for measuring the parameters of submicron aerosols

A new turbidimetric method for determining the parameters of submicron aerosols was developed and implemented in hardware using a wide range of probe radiation wavelengths and high-speed video recording. The particle size distribution function is found using an original algorithm for solving the inverse problem of the optics of aerosols based on a direct search computational procedure..     

Coronary artery numerical flow analysis for determination of bypass graft geometric parameters

A computational investigation of blood flow in a coronary artery grafted by artificial bypass was performed to determine such geometric parameters as the cunvature of radius, approach length, and angle of end to—side anastomosis Transient flow features in the host artery were computed using FVM and SIMPLE algorithms We compared flow distributions and wall shear stresses in two simple models, planar and non—planar, and confnmed that the non—planar bypass model was more conducive to suppressing intimal hyperplasra Our non-planar model with 60° of anastomosis and a 10 diameter appioach length and radius of curvature predicts a relatively small, spatially—extended high-OSI (>0 01) zone, as well as an increased average wall shear stress on this zone     

Surface geometric parameters proposal for the advanced control of abrasive waterjet technology

The paper deals with a proposal for surface geometric parameters for advanced quality control of abrasive waterjet technology according to the results obtained by means of non-contact optical shadow method. The main emphasis is put on the analysis of results for defining the process for prediction of new surface creation generated by the set of the abrasive waterjet factors stream of abrasive waterjet, including its geometric parameters. By means of decomposition of measured surface profile according to the root mean square parameter, in four topographical different zones the initial zone, the smooth zone, the transition zone and the rough zone new possibilities for evaluation of the surface quality and optimizing the selected technological factors of the cutting process and their control through the proposed databank conceptual structure are presented. This report deals with the problems of selecting and proposing an acceptable method for surface quality control which is available for continuous measurement and production.