机器人熔覆3D打印中的成形路径生成研究

介绍了一种基于六自由度工业机器人的熔覆3D打印系统,对打印成形中的成形路径生成进行了研究。根据系统特点开发了机器人扫描路径文件自动生成程序,能够将扫描路径的点坐标与机器人空间姿态及熔覆工艺参数进行组合,生成机器人运动控制程序。进行了成形实验,实验结果达到要求。     

基于图形信息的机器人轨迹控制的研究

针对工业机器人作业时复杂连续路径的离线编程,提出了一种用仿真结果生成机器人控制程序的高效方法。该方法首先从CAD平台提取作业路径模型的控制点信息,通过ADAMS平台对机器人作业过程仿真。然后通过运动仿真结果提取出机器人各关节的转角函数,利用各关节转角函数相应的数据信息直接生成机器人控制程序。最后通过机器人切割作业的模拟实验验证了该方法的可行性和高效性。     

基于AutoCAD的数控铣床图形编程中DXF文件的读取

文章阐述了基于AutoCAD的数控铣床图形编程系统设计中DXF文件的读取问题.数控铣床图形编程系统的设计是通过DXF文件,并加入加工工艺信息等,可以自动地生成ISO标准代码的数控加工程序.在此基础上,图形编程系统可以进行加工过程模拟、NC代码检验.文章重点介绍用于图形编程中的DXF文件如何读入与处理.     

利用VB与Autolisp实现AutoCAD与YH编程系统交换图形

对于一个经济使用YH编程系统的人来说,利用AutoCAD生成的DXF文件向YH传递图形是一件非常平常的事。但是如果要将YH生成的文件向AutoCAD传递则很困难,因为YH系统不能生成DXF、.DWG格式的文件,AutoCAD不能识别。然而在日常的工作中却常常需要将YH生成的文件     

基于PMAC卡数控的G代码自动生成

提出一种基于可编程多轴运动控制器(PMAC)卡的数控G代码自动生成的方法,阐述数控代码自动生成过程.通过分析加工图形的DXF文件,提取图形的坐标信息,自动生成该图形的G代码,然后利用PMAC卡提供的相关功能将G代码转变为PMAC卡可识别的运动程序,并且将运动程序下载到PMAC卡中执行,解决了传统手动输入数控代码的繁琐.经实践表明,该方法能够满足工业加工要求.     

激光叠焊的NC代码自动编程研究

基于DXF文件读取,自动生成NC加工代码,实现设计与加工一体化。介绍了激光叠焊系统的总体组成部分。自动编程系统加载AutoCAD二次开发菜单,在AutoCAD里面参数化绘图和NC代码仿真,嵌入到AutoCAD。分析DXF文件格式,利用VC编写程序接口,读取图元信息。对大圆弧和长直线采用分段搭接的焊接方法,解决一次性焊接行程不够的问题。根据焊接工艺路径要求,优化焊接路径。工程实例表明,NC代码编程系统满足实际工程要求,具有良好的人机界面,操作方便。     

一种实用的平面数控编程方法

采用C语言读取AutoCAD的DXF文件中的图形实体数据,可以很方便地编写生成适合数控车削、平面铣削以及线切割数控程序.实践证明,该方法简单、实用,效益高.     

基于DXF文件的桥切机自动编程

在分析DXF图形交换文件结构的基础上,介绍了从DXF文件中提取图形信息的方法,通过开发的接口程序提取图形信息并转发为加工数据,接口程序中的后置处理模块结合数控加工工艺,将数据转换为机床能够识别的CNC代码,并以此自动生成数控加工程序。     

基于AutoCAD的冲裁零件图形的自动输入与识别

在冲裁模CAD系统中,将产品的图形信息以AutoCAD直接绘图形式输入到计算机中,从AutoCAD的图形交换文件(DXF文件)中提取信息,采用面向对象的二次开发工具ObjectARX和C++语言编写接口程序,并通过封闭轮廓的生成算法自动生成冲裁零件的几何模型,且用单向链表的形式加以表达,同时对冲裁零件图形的轮廓进行分类与走向判定,采用简单的解析几何方法对实体存在侧进行判定,通过对封闭轮廓的适当简化完成了冲裁零件轮廓的凹凸性判定,有效地实现了零件图形的自动输入与识别,为冲裁模CAD系统的工艺计算和模具工作部分的设计等提供了必要的信息。     

平面弯管的计算机辅助设计与绘图

探讨以AutoCAD为图形支撑软件,以C语言为编程语言,通过.DXF文件,将C语言程序的计算结果与AutoCAD的 图形显示连接起来,在AutoCAD系统下显示和输出图样,实现了平面弯管的计算机辅助设计与绘图。     

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...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

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.