基于概念图的民机概念设计要求识别与获取

适航规章要求通常具有高度的概括性和一定的复杂性,为了在民机型号的概念设计阶段准确识别和把握相关适航要求,提出一种基于概念图的民机概念设计要求识别与获取方法。该方法从功能、行为和结构的角度分析适航要求的类型;抽取、提炼适航条款中蕴含的产品设计约束,采用基于概念图本体的方式建立其结构化索引,进而提出基于匹配度的适航要求识别和检索方法,并开发了相应的检索算法,同时进行了软件实现。通过实例检验了所提方法的可行性和有效性。     

装配体公差建模方法研究

为实现装配体公差建模,即在计算机中表示装配体的装配关系和零件本身的公差属性,提出一种综合建模方法,该方法将装配关系模型和零件公差模型相结合.装配关系模型包含父子装配单元之间的从属关系、装配单元之间的约束关系;零件公差模型采用基于关键特征和有向图的建模方法.并结合实例进行了分析验证.     

A view-based approach to modeling product semantics in design chains

To reduce “time-to-market”, semantics of a product must be synchronized in a design chain, because inconsistencies during collaborative product development cause an unnecessary waste of time. To guarantee semantic synchronization, all enterprises should co-operate and maintain semantics whenever they are updated. In this paper, a V2-model is proposed to share product semantics during collaborative product development through view-based semantic synchronization. The V2-model has two kinds of model layers for semantic synchronization: a view-independent model (VIM) layer and a view-specific model (VSM) layer. Semantics in the VIM is the well-structured semantics shared among all enterprises and thus are published across the collaborative design chain. On the other hand, semantics in the VSM is the inconsistent semantics for product information that occurs during the early design stage, when different enterprises may have differing views about product concepts that are constructs of semantics. The inconsistencies between the different views can be solved by a decision and sharing (DnS) process and V2-model. The DnS process transforms the concepts in the VSM to the concepts in the VIM by utilizing topic maps-based scoping and merging functions. The proposed V2-model has been successfully applied to the design process of a washing machine model.     

功能建模法在橡胶分卷机概念设计中的应用

产品的功能设计是概念设计中极为重要的一环,概念设计过程的实质就是一个产品的功能定义、功能分解、功能组合、功能结构的实现并进行方案优化的过程.产品的功能模型对产品的功能语义和功能行为进行描述和表达,在产品设计和分析中具有重要的作用.对功能、功能结构、功能基、功能建模进行研究,运用功能建模法对橡胶分卷机进行功能分析,使其概...     

自下而上产品设计中的自适应装配建模

自下而上的产品建模方法虽在已有信息化设计资源重用以及设计团队协作等方面比自上而下方法有明显优势,但也存在装配冲突、变型困难等缺点.为此提出柔性组件模型及其自适应装配建模方法.基于标准化、系列化、模块化、合理化等原则.建立了产品各组件的包含选型或变型规则的柔性事物特性表和相应的柔性组件模型.利用这种柔性组件进行自下而上的产品装配建模时,根据组件问的装配要求和柔性组件的选型或变型规则,基于简单冲突消除目标或综合优化目标,自适应地选择或调整相关组件并实现有效的产品装配建模.以某织机机架柔性自适应装配建模为例进行了示范,证明该方法有助于提高设计效率,降低设计成本.     

A new history-independent modeling approach for feature-based design

The majority of current feature-based modeling systems employ model history to store feature creation operations and re-execute them sequentially after each modification, which is called history-based modeling. Due to the static feature creation order, history-based modeling causes some problems during the reevaluation of the model, such as the evaluated model does not correspond to its specification, the operation can only refer to the boundary entities created by the previous operations, high computation cost, etc. In this research work, a new history-independent modeling approach is proposed. For the “remove feature” operation, only boundary faces originating from the feature being removed, and the intersecting features are modified for updating the resulting BRep model. For the “modify feature” operation, the feature being modified is first removed from the product model and then re-added with the new specifications, thus its creation step in the model history is changed. As a result, some of the problems caused by the static feature creation order are solved. During the reevaluation, the computation time is dependent solely on the execution of the feature and its intersecting features being edited. The computational complexity of the boundary evaluation using the proposed method for three representative models has been analyzed based on Open CASCADE. A case model was studied in a proof-of-concept prototype system to demonstrate the proposed modeling approach.     

飞机工艺装备模块化设计系统技术研究

模块化设计是产品快速设计的通用技术,是简化产品设计、减少开发成本和缩短研制周期的有效方法之一.基于模块化设计方法,研究飞机工艺装备快速设计技术和飞机工艺装备模块的重复利用技术,开发飞机装配型架设计系统.最后,基于模块实例推理技术实现飞机工艺装备的快速设计.     

Web-based collaborative conceptual design: an XML approach

The highly complex and informal data that have to be managed in the conceptual design phase still lacks of suitable computer support and integration with downstream application, such as the detailed design phase which is supported by lot of computer-aided design (CAD) tools. This paper therefore introduces an object oriented extensible markup language (XML) approach for sharing the users sketching intentions in a collaborative conceptual design environment. A light weight applet-based conceptual design tool is developed using a swing where a user can draw his sketches and store them in an XML format. The system ensures secured seamless integration of data with an in-built engine which automates the workflow once a design seed (initial needs, user requirements and design intentions, etc.) is sowed the system will fertilize it towards a product concept on its own intention. The automated designers’ interactions, on the other hand, will enhance the characteristics and behaviors of the product.     

面向机电产品方案设计的绿色特征建模

针对产品方案设计阶段缺少有效绿色设计理论方法和技术支持的问题,建立了基于绿色特征的机电产品方案设计阶段环境影响信息表达模型。提出了绿色特征的概念,对产品方案设计阶段的各种环境影响信息进行描述。提出基于绿色特征的方案设计阶段信息表达方法。通过绿色特征对绿色信息进行识别、筛选、提取和聚合,最终建立以绿色特征为基础的方案设计环境信息表达模型。以小型通用电机为例,验证了绿色特征的提取过程,并建立了该电机的环境信息表达模型。通过电机具体实例验证了该模型的正确性。     

基于关系对象Petri网的飞机装配系统模型快速构建方法

为支撑飞机装配系统分析与优化,提出了基于关系对象Petri网的装配系统模型快速构建方法.依据现场组织模式分析了装配作业单元分解结构,给出了装配系统关系对象Petri网的模型定义,建立了作业单元对象和关系的表示方法.以模型定义与表示为基础,阐述了装配元对象和逻辑对象模型的构建步骤与规则.采用对象简化网对模型状态空间进行压缩,并建立了基于线性不变量的模型特性验证方法.以某型飞机机翼装配单元为对象进行了实例分析,结果证明了该方法的有效性.     

混流装配线平衡分析与算法设计

为了设计合理可靠的混流装配线并有效地提高装配线的平衡率,分析了混流装配线的特点并设计了一种以工序对调为核心思想的新算法,该算法的逻辑结构较为简易且兼容性高,能够与现有的大部分投产排序方法相结合,对装配线做进一步平衡优化处理.具体地描述了新算法的原理和执行过程,最后将该算法应用到某厂的汽车车灯线束装配线上,结果验证了该方法的有效性和可行性.     

A model-based approach to assembly sequence planning

This paper presents a systematic approach for automatic assembly sequence planning (ASP) by using an integrated framework of assembly relational model (ARM) and assembly process model (APM), which are established by object-oriented method. ARM, consisting of assembly, components and liaisons, is the static model of assembly to describe the geometric relationships between components in terms of contact, constraint and interference matrixes. APM, containing states and sub-processes, is the dynamic model of assembly to represent all potential alternatives in assembly process. An algorithmic procedure is also presented by which APM of an assembly can be constructed systematically by analyzing states from lower levels to higher levels. Through the procedure, all feasible sequences of a product can be generated, and the optimum one can be determined by further evaluating each sequence. To explain the approach more clearly, a practical assembly with five components is used as an illustration in the paper.     

面向装配序列规划的装配建模研究

在分析了层次树状模型与关系网络模型这两种装配模型结构的基础上，根据装配序列规划的要求，应用面向对象的方法建立了满足装配序列规划的产品装配信息模型，提出了相应的数据结构，为虚拟装配序列规划提供了合理的产品信息框架。     

基于数字化装配偏差建模的飞机舱段对接定位方案研究

机身成龙是飞机总装工艺中的一个重要环节,各舱段对接质量直接影响到机身整体外形精度,舱段对接工序中各舱段总成定位方案的选取对于机身外形协调精度具有重要的影响;开展面向飞机机身舱段对接装配的数字化装配偏差建模研究,针对飞机舱段大部件总装对接工艺,采用确定性定位方法对相邻部段对接面位置精度进行分析,建立不同基准定位方案的装配偏差分析模型和评价指数,对比不同定位方案对于装配质量的影响;在某实际机型中后机身与后机身舱段对接协调问题中得到应用验证。     

Kinematic modeling and parameter identification of a new circumferential drilling machine for aircraft assembly

Automated fastener hole drilling is a key technology for low-cost and high-quality assembly of aircrafts. In this paper, a new circumferential drilling machine for fuselage assembly of large aircrafts is introduced. In order to meet the required position accuracy of drilled holes, this paper focuses on the kinematic calibration of the machine in order to improve its positioning accuracy. A modeling strategy, which combines the Denavit-Hartenberg (D-H) method and a modified version of the Hayati-Mirmirani (H-M) method, is proposed to deal with the special kinematic structure of the arc-base drilling unit of the machine. Main issues in kinematic parameter identification such as definition of objective function, calibration data selection, acquisition of initial values, and setting of convergence criteria are also discussed. Experiments of repeatability testing and kinematic calibration have been performed, and the results show that the positioning accuracy of the arc-base drilling unit is comparable to its repeatability after calibration. This suggests that the proposed kinematic calibration method is effective. Actual drilling tests have been performed on a simulated aircraft fuselage after implementing the identified kinematic model in the machine’s control software. Position errors of drilled holes are within ±0.5 mm, which meets the requirement for fastener hole drilling in the fuselage assembly of large aircrafts.     

数据挖掘技术在产品概念设计建模中的应用研究

计算机辅助概念设计(Computer Alded Conceptual Design，CACD)系统的根本目的就在于能有效支持产品的创新设计。本文是在阐述了人、环境和产品数据相互作用的概念基础上，提出基于数据挖掘的动态全息虚拟产品概念设计模型的数学表达式及综合描述，并开发了数据挖掘工具(DM Tool)，实现了从已有的产品库、设计规则库、知识库中挖掘感兴趣的信息和知识，以支持产品概念设计过程。文中以机床主轴箱设计为例，实现了机械产品概念设计过程中的功构映射及机构组合的预测评价，这对CACD的实用研究做了有益的探索。