基于动平衡原理的曲轴质量定心系统研究

针对曲轴实际生产中动平衡效率较低的问题,以总去质量最少为目标,提出一种基于动平衡原理的曲轴质量定心系统。利用曲轴多面校正法进行靠近曲轴端面的去重块的动平衡测算;根据结果,通过影响系数法求出质量定心的影响系数;将所测数据传送给质量定心机上位机系统,根据系统所提供的数据,进行钻中心孔工序。结果表明:该质量定心系统成功减少了曲轴总去质量,实现了曲轴制造工序的优化,有效提高曲轴生产效率和产品合格率,降低曲轴制造成本。     

基于SFC的自动上卷功能的设计及应用

阐述了自动上卷的基本原理和程序控制流程,采用光电开关配合编码器的方法进行钢卷自动宽度对中、采用光电开关组合方法进行高度对中;分析了影响自动上卷过程中高度与宽度自动对中的因素,为自动上卷工程设计提供参考。     

带卷的高度和宽度自动对中及自动上卷

文章阐述了自动上卷过程中不同类型的高度和宽度对中控制的实现方法和基本硬件组成,并介绍了相应的数学模型.分析了自动上卷过程中高度和宽度自动对中的合理配置和工程设计中的各种因素.     

管道机器人超声测量轮廓重建方法的研究

针对大型管道内生物附着物状态的高精度测量需求,提出一种利用齐次变换的轮廓重建方法,通过坐标变换使偏移轮廓的坐标校正回准确轮廓的坐标,消除运动位置偏差引起的轮廓测量误差。通过建立管道超声测量实验装置进行实验验证,得到偏移重建后产生的绝对误差为9 mm、相对误差为2.36%,偏转重建后产生的绝对误差为6 mm、相对误差为1.6%,误差落在超声检测系统的厘米级分辨率之内。后续可以通过提高超声检测系统的分辨率提高轮廓检测精度。该方法可以应用于水下管道轮廓检测以及水下机器人基于轮廓的自动定心探测。     

Construction of a pulse-coupled dipole network capable of fear-like and relief-like responses

The challenge for neuroscience as an interdisciplinary programme is the integration of ideas among the disciplines to achieve a common goal. This paper deals with the problem of deriving a pulse-coupled neural network that is capable of demonstrating behavioural responses (fear-like and relief-like). Current pulse-coupled neural networks are designed mostly for engineering applications, particularly image processing. The discovered neural network was constructed using the method of minimal anatomies approach. The behavioural response of a level-coded activity-based model was used as a reference. Although the spiking-based model and the activity-based model are of different scales, the use of model-reference principle means that the characteristics that is referenced is its functional properties. It is demonstrated that this strategy of dissection and systematic construction is effective in the functional design of pulse-coupled neural network system with nonlinear signalling. The differential equations for the elastic weights in the reference model are replicated in the pulse-coupled network geometrically. The network reflects a possible solution to the problem of punishment and avoidance. The network developed in this work is a new network topology for pulse-coupled neural networks. Therefore, the model-reference principle is a powerful tool in connecting neuroscience disciplines. The continuity of concepts and phenomena is further maintained by systematic construction using methods like the method of minimal anatomies.     

A new capillary gripper for mini and micro parts

In the assembly of microproducts the grasping and releasing phases are key tasks. Since in the microdomain gravity becomes negligible in comparison with adhesion forces, several reliable grasping methods have been developed. On the contrary, the releasing phase is still very critical because the part tends to stick to the gripper. In this paper a novel strategy based on capillary forces both for grasping and releasing is proposed. This novel grasping-releasing strategy exploits the transition between hydrophobic and hydrophilic surfaces to change the grasping force. The paper starts from the releasing problem in microassembly, deals with the manufacturing of hydrophobic and hydrophilic surfaces and demonstrates the use of such structures to grasp and release delicate mini and microparts.     

PCB钻床下钻机构调心装置动力学分析研究

为了提高PCB数控钻床下钻机构的钻孔精度，找出影响下钻机构钻孔精度的原因，对下钻机构中的调心装置进行分析。对调心装置的结构进行简化，采用符合柔性弯曲理论的描述方法描述调心装置中柔性杆的柔性位移，运用哈密尔顿原理，建立调心装置的刚柔耦合动力学模型，并对该动力学模型进行仿真分析。结果表明：调心装置中弹性套的刚度和阻尼系数对调心杆轴端位移有一定影响，弹性套阻尼系数越大，其柔性振动幅值衰减越快；调心偏差对调心装置的振动有较大影响，偏差角越大，调心杆轴端振动越大；增加压缩弹簧可以提高调心杆的刚性，减小调心杆轴端振幅，降低钻孔振动。     

Reconstruction of Freeform Objects with Arbitrary Topology Using Neural Networks and Subdivision Techniques

In reverse engineering, laser scanned data is reconstructed into a CAD model. This paper presents a new reconstruction approach that integrates neural networks with subdivision techniques. The neural network technique creates a triangular mesh that approximates the shape of an object and detects its topology, where the subdivision approach applies smooth surfaces onto this mesh. The advantage of this method is that the reconstruction can be applied on objects with arbitrary topology, and the final model can be integrated with traditional CAD systems using a NURBS representation that preserves continuity. The feasibility of the method is demonstrated on freeform objects with arbitrary topology.     

基于数控加工的三爪小滚子定心夹具移动凸轮设计计算

针对三爪小滚子定心夹具移动凸轮理论曲线复杂、难以在数控机床上直接实现加工的问题,提出三爪小滚子定心夹具移动凸轮的数值计算方法,可有效解决这一数控加工的问题。介绍三爪小滚子定心夹具的结构与工作原理,提出一种对移动凸轮曲线进行等步长采样计算的数值求解方法,将采样得到的采样点按照数控加工容易实现的二次多项式曲线进行插值拟合,然后定义各参数数值,代入数据将利用数值求解方法的二次多项式曲线与实际的理论曲线进行比较,发现在验证的区间内曲线误差远小于利用传统理论曲线加工产生的误差,分析误差比较结果,提出可以通过细化采样步长和分段插值拟合循环计算的方法来提高精度。分析结果表明:利用数值计算方法,可以有效解决移动凸轮不易加工的问题,具有较好的经济效益。     

偏心轴的磨削及配重平衡

采用在重型卧车上粗加工和半精加工,在磨床上精加工的办法加工偏心轴。用数控镗床定心解决了定心精度问题,用固定配重A和可调整配重块B解决了配重平衡问题。     

Adapting CAD models of complex engineering objects to measured point cloud data

Construction, maintenance and retrofitting of complex engineering objects like factories or plants calls for matching their model and actual state that are inevitably different. The paper presents a generic method for tailoring the computer aided design (CAD) model of such objects to their state given in terms of measured 3D, high resolution point clouds. The workflow includes efficient storage of massive measurement data, segmentation of a triangulated mesh-based CAD model into features, matching and adapting the features to the data. The method is demonstrated in a real-world setting, using the CAD model and point cloud data of an industrial plant.     

基于LabVIEW的贮箱多余物检测系统研究及应用

贮箱是大型机械设备中必不可少的部分，其内部铁屑、焊渣等多余物检测的问题有待解决。为实现贮箱内多余物的智能检测，通过时间反转原理的聚焦算法，利用LabVIEW和MATLAB联合编程，设计集数据采集、分析、处理及声发射源定位于一体的LabVIEW软件平台贮箱多余物检测系统。该系统可以有效判断贮箱内多余物的有无及定位，将声发射源的定位以强度图显示。经过多次试验，定位误差控制在5%以内，满足工程需要。     

液压定心机的改进

大冶特殊钢股份有限公司Φ170mm无缝钢管厂液压定心机的液压系统，存在供油能力小于定心机正常生产所需油量的问题、介绍了采用机电液一体化的方法对该厂液压定心机进行改进的成功经验。     

管坯热定心顶锥推力的计算

用解析法和有限元法分析了无缝钢管管坯的热定心过程,得到了在不同工艺条件下的顶锥推力。通过解析法和有限元分析可知:顶锥推力与管坯钢种、定心温度、推进速度、摩擦因数、定心孔大小等有关。所推导的公式及相关计算对热定心设备的选型和模具设计具有理论指导意义。     

Residual stresses and distortions in welded structures: a perspective for engineering applications

Abstract

In this paper, some of the historical developments and recent advances in understanding welding induced residual stresses and distortions are discussed in the context of their impact on today's engineering applications. With recent rapid advances in computational simulation techniques, the complex thermomechanical phenomena associated with typical welding processes can be effectively dissected into solvable problem sets for both fundamental understanding and specific engineering applications. Although a great deal of research is currently still ongoing to advance our fundamental understanding of the complex thermophysical and thermomechanical phenomena, an engineering perspective is provided to demonstrate how an engineer can make use of the current state of knowledge to derive effective practical solutions when dealing with day to day problems in the areas of residual stresses and distortions in welded structures. First, some of the fundamental mechanical considerations associated with residual stress and distortion developments are presented. Then, some of the computational modelling requirements for engineering applications are discussed in the light of recent developments. Finally, application examples are presented to demonstrate how an effective engineering solution can be sought by taking advantage of today's advanced modelling techniques with appropriate engineering assumptions.     

Incorporating interfacial phenomena in solidification models

A general methodology is available for the incorporation of microscopic interfacial phenomena in macroscopic solidification models that include diffusion and convection. The method is derived from a formal averaging procedure and a multiphase approach, and relies on the presence of interfacial integrals in the macroscopic transport equations. In a wider engineering context, these techniques are not new, but their application in the analysis and modeling of solidification processes has largely been overlooked. This article describes the techniques and demonstrates their utility in two examples in which microscopic interfacial phenomena are of great importance.     

MODELING OF MICROMANIPULATION ROBOT IN VIRTUAL ENVIRONMENT

Micromanipulation has been recognized to be very difficult due to the inefficiency of traditional micromanipulation methods. The paper present a general framework for micromanipulation robot based on virtual reality technology.The significance of introducing virtual reality into micromanipulation is analyzed,and the current research in this field is reviewed. Based on this,we propose a micromanipulation system that integrates virtual environment with vision feedback and force feedback.The system realizes vision close-loop control and force close-loop control to enhance the performance of micromanipulation device.A graphics modelling method is proposed for a microassembly task. Hardware and software implementation is described and discussion about the research is presented.     

基于RS-TOPSIS的再制造曲轴毛坯质量评价方法研究*

针对不确定条件下的再制造发动机曲轴质量等级划分问题,研究了基于粗糙集属性约简方法,并将逼近理想解的排序法运用到该问题中。选取主轴颈最大磨损量、连杆颈最大磨损量和主轴颈圆度等10个因素作为再制造曲轴的质量评价指标,利用粗糙集理论的离散和约简算法,将特征属性进行等级划分并计算出对应的特征属性权重,在约简结果基础上建立质量等级评价矩阵,通过计算评价对象的相对贴近度给出了质量分类区间。选取3×200组实测曲轴数据,建立RS-TOPSIS再制造曲轴质量等级评价模型,并对检测样本进行回检,误判率最大为2.1%。结果表明,所采用的RS-TOPSIS评价模型能够对再制造曲轴进行合理的等级评定,能够获得良好的判别效果,具有实际工程价值。     

The processing of data points basing on design intent in reverse engineering

The purpose of this paper is to describe an approach to process the data points, measured from existing objects, for feature-curve fitting in reverse engineering. In the field of reverse engineering, the major problem is that the original measured points with irregular format, and unequal distribution, and lack of appropriate segmentation are difficult to fit into a curve in CAD systems. Therefore, the technology of restoring and segmenting data points is greatly needed to construct the model of an existing object. The proposed approach has been developed to process the measured points with designer interaction to segment and regenerate the data points with the format, in which the points meet the requirements fitting into a B-spline curve with good shape and high quality. This approach consists of five steps: (1) sampling data points; (2) regressing the sampled points into an explicit non-parametric equation; (3) filtering the unwanted points with pre-determined tolerance; (4) regressing the residual points; and (5) regenerating data points from the second-time regressed equation. The proposed approach has been implemented by using an example for practical application, and the result proves the viability of the proposed approach integrating with the current commercial CAD systems.