基于变分几何的参数化造型系统的研究与开发

基于约束的参数化几何造型技术是一种新型、快速的造型方法。本文应用变分几何技术开发了一个参数化几何造型系统——VGPDA。该系统具有自动搜索约束关系,生成约束方程组,进行约束关系一致性识别以及采用符号微分方程法快速求解约束方程组等功能。     

基于ARX的参数化实体造型技术

运用AutoCAD二次开发技术ObjectARX进行参数化实体造型,结合实体造型机制和参数化设计技术．借助保持架模具CAD系统设计实例,阐述了该三维实体造型参数化设计方法。     

CAD系统集成中产品定义的核心——参数化特征造型技术

从CAD系统集成及产品定义的角度,对其关键技术--三维建模技术的传统方法进行论述分析,指出参数化特征造型技术是三维建模技术的发展主流。并以AutodeskMDT为应用实例,介绍了参数化特征造型技术目前的实际应用情况。     

CATIA环境下基于知识的机械产品参数化造型设计研究

提出了一种CATIA环境下基于产品知识的参数化造型方法，并以滚动轴承参数建模为例，建立了产品知识库，定义产品的知识规则，并完成了知识驱动下的产品参数化造型，提高了设计效率。     

参数化及变量化技术在汽车设计中的应用

介绍了参数化，变量化技术的基本原理，参数化设计和变量化设计之间的基本区别以及分别在不同设计环境下的应用。实现轻型货车车身造型元素参数化设计。全面阐述了这两种方法的实际应用及理论基础并讨论了在机械设计、优化设计中的延伸应用。     

基于特征的参数化造型技术族研究与应用

对参数化设计技术、特征技术和基于参数化的特征造型技术做了系统地回顾,在深入地剖析上述技术的基础上,提出了综合运用各技术优点的基于特征的参数化造型技术族的概念及原理。最后给出了以Pro／E为平台,运用基于特征的参数化造型技术族原理于渐开线斜齿圆柱齿轮的实例。     

齿轮实体参数化逆向虚拟造型设计的方法

提出实体参数化逆向虚拟造型设计的方法，介绍应用该方法开发齿轮3维实体参数化虚拟造型设计系统的过程。旨在提供一种对CAD软件开发的新方法，使设计者掌握运用该方法进行实际开发，从而提高开发CAD软件的能力。     

基于Pro/E齿轮参数化造型技术的研究与应用

针对齿轮类零件结构复杂、造型困难、使用频繁的特点 ,本文研究了在Pro/E环境下渐开线齿轮的三维参数化造型技术 ,并介绍了融合该技术和设计人员知识经验的基础上利用VisualC 和Pro/Toolkit开发的纺机常用件三维参数化CAD造型系统。该系统不仅在纺机行业具有一定的通用性 ,其设计思想对其他行业同样具有参考和借鉴价值。     

基于特征的机械产品三维参数化造型研究

介绍将参数化设计应用到特征以及特征造型中去，形成参数化的特征，并可参数化地造型。提出以参数化造型技术构建产品特征的方法和基于特征造型的机械产品三维参数化设计的思想，给出了产品整机三维参数化造型设计的流程。     

基于Pro/E的内燃机零部件建模技术

利用基于特征的参数化造型软件Pro/E,对SF480内燃机的零部件进行参数化造型.并对该机的机体、曲轴、活塞和连杆等三维造型设计中的技术要点进行了探讨,提高了SF480柴油机修改设计和系列化设计的效率.     

基于Pro/E软件的斜齿轮特征造型方法辨析

针对斜齿轮在Pro／E中的特征造型问题,介绍了多种几何建模的方法,经比较分析后,筛选出了精确建模的方法。     

虚拟制造系统建模与仿真

讨论虚拟制造的有关概念，虚拟制造建模与仿真环境及该环境下的产品与制造过程建模，虚拟制造建模与仿真的支撑技术等。     

特征造型系统中的参数化设计技术应用研究

特征造型技术是实现ＣＡＤ／ＣＡＰ／ＣＡＭ集成的关键技术之一，其先进性要求它除了信息完备以外，还应与参数化设计技术有机结合起来，从而实现已建模型的动态修改，提高设计的自动化程度。本文介绍了在一个特征造型系统中参数比设计技术的具体应用与方法。     

Rapid Prototyping Applications in Medicine. Part 2: STL File Generation and Case Studies

Rapid prototyping (RP) technology has extended traditional manufacturing applications in areas other than product engineering. Using RP to fabricate custom implants and prosthesis for surgical planning and education is now an important area of research. Although, in theory, RP is capable of producing objects of any complexity, designing freeform shapes is difficult using current CAD systems. These CAD systems are geared toward the design of parts manufactured by traditional methods; they do not help designers exploit the expanded opportunities offered by RP technology. Medical data cannot be input into these CAD systems directly for further modification and manipulation. The purpose of this project is to explore a new approach for modelling and prototyping biomedical objects. The work extends from volume modelling to RP and medicine. In Part 1 of two papers, a new approach to modelling complex objects, NURBS-based volume modelling, is proposed. A NURBS representation of volumes is developed to represent not only the surface boundary but also the interior of a 3D object. NURBS-based volume modelling inherits advantages from both NURBS modelling and voxel-based modelling. The key idea of the NURBS-based volume modelling is to exploit the flexibility of NURBS modelling and use the voxelised NURBS volumes as components for constructing complex objects. This paper, Part 2, deals mainly with issues of interfacing volume models to RP systems. A new approach to generate STL files through volume modelling and iso-surface extraction is proposed. This approach guarantees the validity of the final STL file inherently. Software development and case studies are also given.     

Constraint-force-based approach of modelling compliant mechanisms: Principle and application

Numerous works have been conducted on modelling basic compliant elements such as wire beams, and closed-form analytical models of most basic compliant elements have been well developed. However, the modelling of complex compliant mechanisms is still a challenging work. This paper proposes a constraint-force-based (CFB) modelling approach to model compliant mechanisms with a particular emphasis on modelling complex compliant mechanisms. The proposed CFB modelling approach can be regarded as an improved free-body- diagram (FBD) based modelling approach, and can be extended to a development of the screw-theory-based design approach. A compliant mechanism can be decomposed into rigid stages and compliant modules. A compliant module can offer elastic forces due to its deformation. Such elastic forces are regarded as variable constraint forces in the CFB modelling approach. Additionally, the CFB modelling approach defines external forces applied on a compliant mechanism as constant constraint forces. If a compliant mechanism is at static equilibrium, all the rigid stages are also at static equilibrium under the influence of the variable and constant constraint forces. Therefore, the constraint force equilibrium equations for all the rigid stages can be obtained, and the analytical model of the compliant mechanism can be derived based on the constraint force equilibrium equations. The CFB modelling approach can model a compliant mechanism linearly and nonlinearly, can obtain displacements of any points of the rigid stages, and allows external forces to be exerted on any positions of the rigid stages. Compared with the FBD based modelling approach, the CFB modelling approach does not need to identify the possible deformed configuration of a complex compliant mechanism to obtain the geometric compatibility conditions and the force equilibrium equations. Additionally, the mathematical expressions in the CFB approach have an easily understood physical meaning. Using the CFB modelling approach, the variable constraint forces of three compliant modules, a wire beam, a four-beam compliant module and an eight-beam compliant module, have been derived in this paper. Based on these variable constraint forces, the linear and non-linear models of a decoupled XYZ compliant parallel mechanism are derived, and verified by FEA simulations and experimental tests.     

Rapid Prototyping Applications in Medicine. Part 1: NURBS-Based Volume Modelling

Rapid prototyping (RP) technology has extended traditional manufacturing applications in areas other than product engineering. Using RP to fabricate custom implants and prostheses for surgical planning and education is now an important area of research. Although, in theory, RP is capable of producing objects of any complexity, designing freeform shapes is difficult using current CAD systems. These CAD systems are geared toward the design of parts manufactured by traditional methods; they do not help designers exploit the extended opportunities offered by RP technology. Medical data cannot be input into these CAD systems directly for further modification and manipulation. The purpose of this project is to explore a new approach for modelling and prototyping biomedical objects. The work extends from volume modelling to RP and medicine. In this paper, Part 1 of two papers, a new approach to modelling complex objects, NURBS-based volume modelling, is proposed. A NURBS representation of volumes is developed to represent not only the surface boundary but also the interior of a 3D object. NURBS-based volume modelling inherits advantages from both NURBS modelling and voxel-based modelling. The key idea of the NURBS-based volume modelling is to exploit the flexibility of NURBS modelling and use the voxelised NURBS volumes as components for constructing complex objects. Part 2 deals mainly with issues of interfacing volume models to RP systems. A new approach to generate STL files through volume modelling and iso-surface extraction is proposed. This approach guarantees the validity of the final STL file inherently. Software development and case studies are also given.     

An object-oriented simulation and extension for tandem AGV systems

An object-oriented simulation modelling environment, AgvTalk, is presented to provide flexible modelling capabilities for the simulation of many alternative automated guided vehicle (AGV) systems. The hierarchical features and modularity of AgvTalk create possibilities for the extension and reuse of simulation object components. The detailed behaviour of each object in the AGV system can also be modelled easily and exactly in AgvTalk because there are no limiting modelling constructs. The modelling capabilities of AgvTalk are demonstrated by designing and simulating a conceptually different configuration AGV system, known as the tandem configuration. For the tandem and conventional AGV systems, the characteristics and design methodology in AgvTalk are described. Simulations between the two systems are compared using AgvTalk in a job shop environment.     

基于虚拟现实的机器人遥操作关键技术研究

机器人遥操作是实现空间、医疗及深海等领域作业的重要手段,基于虚拟现实的机器人遥操作是克服时延的有效方法,具有透明性强、稳定性高的优点,成为当前机器人遥操作的主要方式。首先分析了基于虚拟现实的机器人遥操作系统的关键组成部分,并对其关键模块的具体作用进行了介绍;其次,归纳分析了各类虚拟现实环境建模方法,主要从几何建模和动力学建模方面展开,阐述了每种方法的应用领域、主要特点;此外,进一步分析了遥操作虚拟夹具设计的构建方法及适用领域。最后对当前存在的难点进行总结,指出今后研究的思路。     

Adaptive modelling of transient vibration signals

Conventional vibration signal processing techniques are most suitable for stationary processes. However, most mechanical faults in machinery reveal themselves through transient events in vibration signals. Time-series modelling, including autoregressive moving average (ARMA) modelling and autoregressive (AR) modelling, is an efficient approach for transient signal analysis. Based on the adaptive prediction technique, this paper applies the principle of the adaptive line enhancer (ALE) to the modelling of transient vibration signals. The time-series models, adaptive algorithms and the rational time–frequency transfer function are investigated in the paper. Simulation and experimental studies with different time–frequency–amplitude distributions and transient vibration responses are described. The results show that the adaptive modelling method can trace the time–frequency signal and extract dynamic features such as time–frequency distributions and time–amplitude distributions from sample signals. Given the simple programming and potentially easy implementation in on-line applications, this method should have application in machine monitoring and fault diagnosis.