Para-Graph: Graph-Based Parameterization of Triangle Meshes with Arbitrary Genus

This paper describes a novel approach to the parameterization of triangle meshes representing 2‐manifolds with an arbitrary genus. A topology‐based decomposition of the shape is computed and used to segment the shape into primitives, which define a chart decomposition of the mesh. Then, each chart is parameterized using an extension of the barycentric coordinates method. The charts are all 0‐genus and can be of three types only, depending on the number of boundary components. The chart decomposition and the parameterization are used to define a shape graph where each node represents one primitive and the arcs code the adjacency relationships between the primitives. Conical and cylindrical primitives are coded together with their skeletal lines that are computed from and aligned with their parameterization. The application of the parameterization approach to remeshing guarantees that extraordinary vertices are localized only where two patches share a boundary and they are not scattered on the whole surface.     

Controller parameterization for SISO and MIMO plants with time delay

Controller parameterization is a very fundamental problem in control theory. It provides an elegant and efficient way towards solving the stabilizing and design problem, with which all stabilizing controllers are characterized and thus a constrained design procedure can be replaced by an unconstrained optimization. In this paper we deal with the problem of characterizing all stabilizing controllers for single-input/single-output (SISO) plants with time delay and multi-input/multi-output (MIMO) plants with multiple time delays. A new parameterization is derived on the basis of the definition of the internal stability. The new parameterization does not depend on the coprime factorization of the plant and has similar form to that of the Youla parameterization for stable plants. An important merit of the proposed parameterization is that it reflects the internal model control (IMC) structure and thus has a very simple relationship to the sensitivity function and complementary sensitivity function. Numerical examples are given to illustrate the proposed parameterization.     

考虑结构非线性特征的参数化形状优化方法

提出并实现一种将参数化设计技术应用于考虑结构非线性特征的形状优化设计领域的新方法。参数化设计技术是近年来发展起来的新一代CAD软件平台的核心技术之一。文中基于三维参数化CAD平台，将参数化设计技术、有限元建模技术与有限元分析优化系统集成为参数化的形状优化系统；引入非线性分析技术，以解决工程上大量存在的非线性形状优化问题。该方法克服了以往形状优化方法应用于三维实体结构时所面临的几何形状描述、约束与驱动的困难，为机械产品三维结构优化设计提供一个新途径。     

Pro/Engineer软件在振动筛设计中的应用

用Pro／E软件对振动筛进行特征参数化造型设计，利用注塑模具计算注塑面积的方法计算振动筛叠层滤网透筛率、平动椭圆振动筛设计的关键技术力心与质心自动重合的方法，为提高振动筛的设计效率、推出新产品提供了有力的支持。     

基于参数化的机床产品快速变型设计

在产品的概念设计过程中,融入参数化技术,实现大规模定制化产品的快速设计.针对机床产品,以UG为软件平台,结合V C 和SQL Server数据库开发机床产品参数化变型系统,并讨论从功能需求到结构参数模型的映射过程、主要结构特征尺寸参数化等关键技术,通过参数化实现产品级的机床快速变型设计.     

基于XML的产品数据交换及协同设计技术

提出了一种新的基于 XML (可扩展标记语言 ,e Xtensible Markup L anguage)的产品数据交换标准及存储方法。应用 XML描述设计中各图素、特征及其关系 ,保留了设计历史 ,以适应异步协同设计中数据交换时设计者之间对设计过程的相互了解。采用传输 XML表达的设计语义而不是三维实体模型的数据交换方法 ,极大地减小了网络传输量 ,满足了同步协同设计过程中实时、同步的显示和造型要求。设计实例验证了该方法的有效性     

二阶线性系统全维PI观测器的参数化设计

基于一类广义Sylvester矩阵方程的解．提出了二阶线性系统的全维PI观测器设计参数化方法．给出了该类观测器的增益矩阵和左特征向量矩阵的参数化表达式．该观测器设计的参数化方法直接基于二阶线性系统的参数矩阵,不涉及系统的变换或增广．数值例子表明了所提方法的简单有效性．