复杂机电产品全三维工艺设计系统研究

针对目前复杂机电产品中高精度、薄壁及异形复杂腔体类零件加工工艺复杂,设 计周期长及后续车间制造检验工人识图不直观等问题,提出并构建了基于MBD 的C/S、B/S 混 合架构全三维工艺设计系统。阐述了系统的体系结构和实施工作流程。详细研究了设计工艺 MBD 模型构建过程中单元信息标识、组合框格标识、三维标注、动态工艺模型构建以及全三维 工艺规程卡构建关键技术。最后,给出了开发与应用实例。研究结果表明,该系统能使设计制 造过程基于统一全三维模型源,有效缩短了传统3D→2D→3D 过程总研制周期,降低了研制成 本。     

基于模型的工艺信息标识方法研究

实现工艺信息在三维模型上的标识是目前三维数字化工艺研究的热点。针 对此问题,论文提出了一种基于MBD 技术和GB/T 24734-2009 的机加工工艺信息标识方法。 该方法有效地规范了机加工工艺信息标识符号的构建和组合方法,并通过三维标注实现工艺 信息与模型的关联,使工艺设计人员和制造人员能快速直观地浏览与获取加工工艺信息。在 以上研究的基础上,基于Pro/E 平台进行二次开发,并通过实例验证了该方法的可行性和实 用性。     

基于AutoCAD的线性标注

线性标注是尺寸标注的一种,描述的是任意两点之间的水平或垂直距离.在二维平面图的绘制过程中,线性标注比较简单,但在等轴测图及三维模型图的绘制过程中,标注却是一件棘手的事从多年AutoCAD教学和制图经验中,总结出线性标注在二维平面图、等轴测图及三维实体图中的标注方法,与广大同仁分享学习.     

基于 MBD 的三维图样表达方式研究与系统实现

针对现有三维图样技术在实际应用中存在的主要问题,提出了设计视图、模型与 标注分区显示、集成标注等具体方法,解决了目前三维图样信息显示不清晰、无法满足复杂产 品信息定义需求等关键问题。结合数字化环境下产品信息表达与数据一致性等需求,采用信息 结构树保证了几何与非几何信息间的关联性。给出了三维图样系统的具体设计方案,以及相应 可视化功能的具体实现方法,实现了基于 ACIS 与 HOOPS 联合平台的三维图样软件系统开发, 在该系统中完成了典型零件的精度设计,验证了三维图样软件系统的实用性。     

领域自适应的合成词词性标注研究

在词性标注研究中,未登录的专业领域合成词给词性标注增加了很大的困难。本文提出了一种领域自适应的合成词词性标注方法,融合支持向量机（SVM）模型和基于转换学习（TBL）的方法来进行自动词性标注。对专业领域合成词的形态特征进行了详尽的分析,对有关的语法特点和语言现象进行总结。有效利用这些合成词构词单元的语言学信息,把词类和词内结构信息引入SVM特征选择模板和TBL转换规则模板中,并采用核心属性渗透方法标注专业领域合成词的词性。实验结果表明,该方案能够有效地提高词性标注的准确率。     

基于差异特征协同语义标注的三维模型检索方法

提出一种基于差异特征协同语义标注的三维模型检索方法.该方法利用多种特征提取方法的优点,借鉴半监督学习中的协同训练思想,首先通过3种差异特征提取算法分别训练学习器,构造出3个差异学习器;然后通过协同迭代训练找到最优学习器对三维模型进行自动语义标注;最后结合语义进行三维模型检索.在普林斯顿大学的PSB三维模型数据集上的实验...     

基于HMM的柯尔克孜语词性标注的研究

柯尔克孜语的语言信息处理研究,对新疆柯尔克孜族是否能跨入信息时代,传承民族文化起着至关重要的作用。采用两级标注法,基于传统的HMM理论,改进了HMM模型参数的计算、数据平滑和未登入词的处理方法,更好地体现了上下文依赖关系。同时,把基于自动分词词典的词干提取算法与规则和统计相结合的方法用于柯尔克孜语的词性标注系统上。相对于传统的HMM,改进后的方法有效提高了准确性。     

基于数控加工的工艺设计原则及方法研究

为了提高数控车床的使用效率,科学地运用编程技巧,编制高效率的加工程序,我们有必要对数控加工工艺设计原则及方法进行研究。本文通过介绍数控加工的工艺特征,数控加工工序的划分原则、设计数控加工工艺过程需遵守的原则以及走刀路线设计方法、Master CAM技术方法,为提高数控机床的使用效率提供了一些意见。     

发动机数字化设计三维标注的几个关键技术

正MBD模型是最先进的设计信息传递模式。为了充分利用三维模型所具备的表现力,去探索便于用户理解、更具效率的设计信息表达方式,着重对发动机数字化设计三维模型标注所涉及的若干关键技术进行了论述与分析,包括三维模型标注的基本原则和特点,发动机三维模型的视图、尺寸、公差、技术要求及标题栏标注等,提出了相应的解决问题思路和技术手段。     

基于OpenGL的数控仿真三维图形的研究

数控加工过程由数控程序控制,但数控程序的错误往往不容易被发现。从而在实际加工中可能出现碰撞干涉等问题。通过数控仿真软件可以在制造之前在计算机中模拟加工过程,发现可能出现的碰撞、干涉,零件的可加工性及工艺的合理性等。而在虚拟加工环境下,三维图形处理是其核心的技术问题。本文以三维图形软件标准OpenGL为工具,探讨数控仿真系统中三维图形的处理方法。     

汽车传动轴防尘罩PLC控制系统的设计与实现

本文介绍了PLC和变频器在汽车传动轴防尘罩高低温控制系统中的成功应用,介绍了系统控制方案和软硬件结构的设计思想。提出了一种易于在PLC中实现的适用于被控对象为二阶惯性环节温度预测控制系统,实际运行表明该算法优于常规的PID算法。本系统功能强,性能好,精度高。     

Convergence of Markov chain approximation on generalized HJB equation and its applications

This work is concerned with numerical methods for a class of stochastic control optimizations and stochastic differential games. Numerical procedures based on Markov chain approximation techniques are developed in a framework of generalized Hamilton-Jacobi-Bellman equations. Convergence of the algorithms is derived by means of viscosity solution methods.     

Integration of control system design and implementation over the internet using the Jini technology

This paper describes an approach for the integration of control system software design, testing, and implementation over the Internet using the Java and Jini technologies. Process models and control systems are remotely designed and tested in a virtual laboratory (also called the virtual world), and then implemented in a physical plant (also called the real world) through an integrated environment. Although control system and process model designers and real‐site operators are geographically dispersed they work together as a team over the Internet to provide the maintenance support to all the authorized industrial processes. As a consequence, time and money can both be saved because there is no need for an expert of the control software supplier to travel to the site of the real plant and conduct on‐site implementation. A generic control system life cycle model is presented first in this paper. Then three enabling technologies including Java, Jini and WWW are briefly introduced. Taking advantage of the Java, Jini and WWW technologies, an Internet‐based general infrastructure is proposed to remotely facilitate process modelling, control system design, simulation, validation and on‐site implementation. An integrated environment is established to implement the infrastructure. A water tank with a liquid level control system is refereed as a case study to illustrate how the prototype of the integrated environment works over the Internet. Further work and the conclusions are given at the end. Copyright © 2003 John Wiley & Sons, Ltd.     

PSO-based intelligent integration of design and control for one kind of curing process

In this paper, a PSO-based intelligent integration of design and control is proposed for one kind of nonlinear curing process. This method combines the merits of both fuzzy modeling/control and PSO method, where fuzzy modeling/control is proposed to approximate/control the nonlinear process in a large operating region and the PSO-based intelligent optimization method is developed to solve non-convex and non-differential integration problem with design and control optimized simultaneously. Finally, the proposed method is compared with the traditional sequential method on controlling the temperature profile of a nonlinear curing process.     

The development and application of CAD/CAM workstations in the GDR

For accomplishing low-attended manufacture, step by step, it is necessary that information handling in technological production planning, management and shop control processes is organized economically. This is especially true with respect to computer-aided product development and production planning, faster order throughput, control of production equipment and delivery of information needed for high equipment utilization with a simultaneous increase in the volume of data processed automatically. These complex requirements call for a new type of approach in information handling technology (CAD/CAM) and corresponding layouts of workstations for the designer and manufacturing engineer. Such CAD/CAM facilities should be user-friendly so that they can be adapted to the user's need and not vice versa.     

Implementation and testing of an advanced relay auto-tuner

In this paper, an advanced relay feedback auto-tuner for single-loop controllers is presented. The tuner combines an improved relay feedback process frequency response identification method and a multiple-point frequency response fitting controller design method. In process identification, multiple accurate points on the frequency response curve of a process are obtained in one single relay feedback test. A controller is then designed based on these estimated points using frequency response fitting methodology. The auto-tuner was implemented on a personal computer with AD/DA card. The software was developed on a commercial real-time control platform. The algorithms were written in C++ and compiled as a Dynamic Link Library. The auto-tuner has been tested on a dual-process simulator which can be easily configured as various typical processes, and on pilot coupled-tank and heat exchanger. The testing results show that the tuner gives significant performance improvement over the standard relay auto-tuner.