三维CAD技术及其系统开发

介绍了三维CAD技术的意义与作用,三维CAD技术的发展历程及发展趋势,并对三维CAD系统的设计与开发作了简要的分析。     

CAD环境下机械设计建模及应用

通过分析常见的CAD技术建模方法,阐述了CAD技术模型构建的具体过程,从特征创建中的要点,添加约束的技巧,参数化设计中的注意事项等方面提出了建模中的注意事项。     

液晶显示计算机辅助设计与分析

通过对液晶显示的指向矢空间分布和电光特性等模拟计算,对液晶显示进行计算机辅助设计与分析等模拟计算.该模拟计算适用于TN与STN、对称与非对称、透射式与反射式等各种液晶盒,在新型液晶显示器的开发与分析中,有广泛的应用前途.     

液晶显示计算机辅助设计与分析

通过对液晶显示的指向矢空间分布和电光特性等模拟计算 ,对液晶显示进行计算机辅助设计与分析等模拟计算。该模拟计算适用于 TN与 STN、对称与非对称、透射式与反射式等各种液晶盒 ,在新型液晶显示器的开发与分析中 ,有广泛的应用前途     

液晶显示计算机辅助设计与分析

通过对液晶显示的指向矢空间分布和电光特性等模拟计算,对液晶显示进行计算机辅助设计与分析等模拟计算.该模拟计算适用于TN与STN、对称与非对称、透射式与反射式等各种液晶盒,在新型液晶显示器的开发与分析中,有广泛的应用前途.     

Automated three-dimensional X-ray analysis using a dual-beam FIB

We present a fully automated method for three-dimensional (3D) elemental analysis demonstrated using a ceramic sample of chemistry (Ca)MgTiO(x). The specimen is serially sectioned by a focused ion beam (FIB) microscope, and energy-dispersive X-ray spectrometry (EDXS) is used for elemental analysis of each cross-section created. A 3D elemental model is reconstructed from the stack of two-dimensional (2D) data. This work concentrates on issues arising from process automation, the large sample volume of approximately 17 x 17 x 10 microm(3), and the insulating nature of the specimen. A new routine for post-acquisition data correction of different drift effects is demonstrated. Furthermore, it is shown that EDXS data may be erroneous for specimens containing voids, and that back-scattered electron images have to be used to correct for these errors.     

Complex CAD surface shape design using semantic features

To a large extent, the success of the product shape design depends on whether the geometric modeling systems can satisfy more and more complicated design demands in the engineering field. This paper proposes a shape design method based on semantic features for complex CAD surface. By the proposed method, we can easily meet the complicated design requirements, since the semantic can effectively represent the design intent. We discussed three aspects in shape design using semantic features, which are semantic design demands of the target surface, geometric constraints in accordance with semantic features, and surface shape deformation under the geometric constraints, respectively. The basic semantic features of geometric models drive the deformation of the target surface shape by changing the related constraint, and the desirable features are added to the CAD surface shape. The examples of the car shape design are presented to verify the effectives of our method.     

LED显示屏系统驱动电路设计

LED显示屏是利用发光二极管组成的平面式显示屏幕。本文首先简要介绍了LED显示屏系统的基本结构，接着对一种单色LED显示屏系统的驱动电路设计进行详细的描述，最后介绍了单片机的程序设计流程．     

Propagation of design change between different CAD by using duplicate design procedures

Design change can become difficult to propagate when the CAD software used in industrial design and mechanical design is incompatible. Different CAD systems typically adopt neutral formats as the standard form to conduct exchanges between files. Because these neutral formats cannot keep the details of the design features, this work presents a novel approach to achieve design change propagation. First, the macro type passing data (MTPD) is employed to record design procedures, and the similarity comparison is adopted to identify the differences between two input models for the mechanical design. By noting the differences in corresponding elements in both models, designers can adjust the MTPD from the old mechanical design, which was added on the first input model and applied onto the following input model. The design change propagation between industrial design and mechanical design is then concluded. This modified MTPD can duplicate design procedures in both standalone and server–client edition in our research. Users who only use a web-page viewer can now also view the propagation collaboratively.     

Integrated CAD of mechanisms

There are three major components in an integral linkage design package: synthesis, analysis and design/drafting. Through the utilization of existing design software and integration tools, such a system is being developed at the University of Minnesota. This paper presents the prototype system along with a detailed example. The system, not yet all encompassing, ties the three major components together into one useful design tool utilizing LINCAGES for synthesis, DRAM for analysis, and ICEM DESIGN/DRAFTING for the design/drafting component. The example illustrates the use of the package in the design of a six-bar stamper mechanism. The design process is followed through from initial problem definition to the final analysis of the mechanism.     

新型扭矩电动扳手显示的设计

介绍了新型电动扳手显示系统的设计,并基于I2C（Inter—Integrated Circuit）总线技术实现LCD（Liquid Crystal Display）的显示。给出了硬件电路的设计和软件流程图。该设计可简化硬件电路,提高扭矩精度,使电动扳手小巧、轻便、美观,性能安全可靠。     

基于面向对象的搅拌反应釜CAD系统的分析和设计

介绍了基于面向对象的搅拌反应釜CAD系统的开发过程，实现了搅拌反应釜的结构设计、强度计算及设计说明书与设计图的自动生成。     

三维设计中的设计思想与意图体现

运用现代三维设计软件,通过对典型零件设计与三维设计软件功能的研究,分析如何将设计思想融入三维设计软件的应用过程中。重点从特征建模与设计关系、建模过程与加工工艺设计思想等方面进行研究,总结现代产品设计开发过程中如何体现设计者设计思想和意图的方法。通过这些方法,设计者可更好地将设计思想融入三维设计过程,更好地运用三维软件解决实际问题。     

基于特征的零件CAD系统设计

特征建模技术是实现CAD／CAM集成的核心,根据CAD／CAM集成化的要求,以现有的几何造型CAD系统为基础,建立零件的特征模型,将零件的几何信息与加工工艺信息有机的联系在一起,并介绍了所开发的基于特征的轴类零件CAD系统,该造型系统可以满足CAD／CAPP／CAM集成的要求。     

CAD建模与优化设计

从ＣＡＤ建模出发提出优化设计问题,从工程应用角度解决用数模进行优化设计时的困难,通过实例解决了ＪＫＹ２．５／２Ｂ型提升机卷筒的优化设计问题。     

CAD──一场设计的革命

CAD作为一种高效的生产力手段,正冲击着传统的设计方式,引起了一场设计的革命。本文简要地介绍了CAD使传统设计方式发生质的变化,当今CAD技术的特点、趋势以及应用体会。     

连杆机构运动分析的解析设计

建立连杆机构运动分析的计算模型，并应用VB语言进行求解，提高设计精度。     

凸轮CAD/CAM系统开发

本文以摆动滚子从动件盘形凸轮为例,对如何模拟凸轮轮廓曲线进而设计出方便实用的凸轮CAD/CAM系统进行了较为深入的分析探讨。文中介绍了凸轮CAD/CAM系统结构,功能分析与界面分析,所需确定的参数以及选用主题程序的算法等关键性问题。     

Triaxial joint moment estimation using a wearable three-dimensional gait analysis system

We developed a wireless sensor system composed of a mobile force plate system, three-dimensional (3D) motion sensor units and a wireless data logger. Triaxial joint moments of the ankle, knee and hip joints were calculated using measurements of the sensor system. The accuracy of the joint moment estimation is validated against results obtained from the reference measurement system composed of a camera based motion analysis system and force plates. Triaxial joint moments measured by the sensor system showed normalized root mean square error (NRMSE) and correlation coefficient (R) of less than 22% and more than 0.80 in comparison with the stationary system.     

Conceptual design of compliant mechanisms using level set method

We propose a level set method-based framework for the conceptual design of compliant mechanisms. In this method, the compliant mechanism design problem is recast as an infinite dimensional optimization problem, where the design variable is the geometric shape of the compliant mechanism and the goal is to find a suitable shape in the admissible design space so that the objective functional can reach a minimum. The geometric shape of the compliant mechanism is represented as the zero level set of a one-higher dimensional level set function, and the dynamic variations of the shape are governed by the Hamilton-Jacobi partial differential equation. The application of level set methods endows the optimization process with the particular quality that topological changes of the boundary, such as merging or splitting, can be handled in a natural fashion. By making a connection between the velocity field in the Hamilton-Jacobi partial differential equation with the shape gradient of the objective functional, we go further to transform the optimization problem into that of finding a steady-state solution of the partial differential equation. Besides the above-mentioned methodological issues, some numerical examples together with prototypes are presented to validate the performance of the method.