约束网络及约束传播技术在并行设计中的应用研究

探讨人工智能中的约束网络及约束传播技术的并行设计中的应用,先将设计变量构成约束网络,通过约束传播技术使得设计变量趋于精确,并将推理依据进行记录,在发生冲突时系统呆以根据所记录的约束来源协调设计过程,达到协同设计的目的。     

敏捷制造环境下装配产品变形设计方法

为了获得满足顾客个性化需求的装配产品设计方案 ,提出了通过修改现有成熟零件的设计的变形设计方法。建立了描述装配产品构成零件之间配合关系的模型并识别出反映装配产品构成零部件之间尺寸关联关系的约束组。每个约束组的变形设计过程被归结为一个混合整数线性规划 (MILP)问题 ,而所有约束组的MILP问题的组合求解过程则反映了装配产品的变形设计优化过程。开发了软件原型系统并进行了仿真 ,仿真结果表明该方法能够在合理的时间内获得新的、可行的装配产品设计方案 ,可以作为装配产品设计方案的生成器 ,以缓解顾客个性化需求对产品设计带来的压力     

基于约束的协同设计冲突检测技术研究

为了有效地辅助设计人员及时发现冲突并适时提供有效的冲突解决方案，分析了协同设计中约束的内涵及其动态性和层次性等特点，对约束满足问题进行了形式化表达。采用遗传算法作为协同设计过程中约束满足问题的求解方法，给出了该算法的具体实现过程。采用可扩展标记语言对网络环境下系统约束信息的数据进行了描述。在此基础上，提出了基于约束的冲突检测系统的体系结构，并对主要组成模块的功能进行了详细描述。开发了该冲突检测系统的原型系统并对其运行过程进行了描述。通过某车床纵向进给部件的圆柱齿轮减速机构的设计实例，说明了该系统的有效性。     

分层参数化设计方法及其在产品快速设计系统中的应用

在详细分析现有参数化设计方法在产品设计过程中不足的基础上,提出了产品的分层参数化设计方法,并对各层间的约束的求解和传递进行了详细论述,并据此开发了某飞机蒙皮结构模具的快速设计系统.     

基于约束的分布式产品特征设计系统

面向分布式产品设计活动的管理与控制,基于特征和约束技术,本文提出了一个分布式产品设计系统,对系统的结构、方法和应用实例进行了说明。采用特征和约束来建立产品模型,并通过特征算法来控制和协调分布式产品设计活动。     

多学科协同设计的约束网络模型研究

通过对多学科协同设计中约束特点的分析，提出了一种对产品进行多学科协同设计的约束网络模型，该模型从产品的组成和设计过程两方面多层次地将产品的各学科子模型关联起来。能够有效地支持产品多学科协同设计过程。给出了约束网络模型的表达方法，并以汽车离合器为例进行了实例分析。     

管线布局设计的约束因素分析及建模方法研究

布局设计是一个基于约束空间的求解过程，而影响布局设计的约束因素又是复杂多变的，针对工程领域的管线布局设计问题，提出了约束元，约束集，约束方法，约束度，约束链和关联约束子集等概念，并应用这些概念对影响管线布局的约束因素进行了分析，进而给出了基于目标分解的管线布局建模方法。     

基于设计任务链重用的产品再生设计技术研究

为实现产品再设计过程的知识支持,提高产品开发效率与质量,提出了基于设计任务链重用的产品再生设计方法.采用任务链动态地描述产品设计过程,通过向量模型.实现设计任务链的抽取,利用约束传递方法,实现多个产品实例局部任务链的融合.该方法在低压电器产品开发中得到了应用验证,对提高产品设计过程的可拓性与重用性起到了较好的作用.     

配置设计的分级约束满足问题求解方法研究

从分析配置设计过程中约束对变量的不同作用程度入手,提出将配置求解过程作为分级约束满足问题进行处理,对约束进行分级处理,赋予不同的约束水平,以确定配置求解过程中约束满足的顺序。通过引入"活动变量"和"活动约束",对有向图中结点和弧赋予新的含义,构建了分级约束满足问题网络,采用一致性方法和基于图的传播技术相结合的方法进行网络的一致性检验和约束的传播,并提出了分级约束满足问题网络在求解过程中约束冲突的解决方法,形成了配置设计的分级约束满足问题求解方法,较好地解决了变量受多个不同强度约束条件作用时的合理赋值和约束冲突的问题。并以捆钞机产品配置为例,验证了分级约束满足问题求解方法的可行性。     

约束驱动的动态关联式装配验证系统的设计与实现

针对机械产品设计中的装配约束验证问题,采用构造装配约束验证树的方法,将机械产品设计中存在装配约束关系的信息存储在树的节点中,将修改后的设计参数存入修改器,使用监视器监视修改器内容的变化,并对验证树进行实时更新,通过验证分析器调用监视器中的堆栈信息来决定验证工作的启停,实现了装配约束关系的动态、关联验证。开发了一个动态关联式装配验证原型系统进行实例验证,结果表明,该系统能够与设计同步监测设计变化对约束关系的影响,动态地检测出违反装配约束关系的设计缺陷。     

AUTOMATIC APPROACH TO PRODUCT CONCEPTUAL DESIGN BASED ON CONSTRAINT NETWORK

Product design is considered as the constraint satisfaction problem (CSP), and a new design approach basedon constraint network is proposed and applied to make design automatic partially. By means of constraint extraction, constraint network construction and operation, constraint chains are acquired, and then the conceptual design scheme can be got by decoding the information stored in the design constraint chains, which provides a novelty method for mechanical product design automation. Shearing mechanism of shearing machine has been designed by this way.     

基于动约束求解的协同设计研究

协同设计是由多功能小组共同参与到产品开发过程中的设计方式 ,良好的任务关联和分解是协同设计的前提和保证 ,任务分解使多功能小组之间必然存在许多的相互制约、相互依赖的关系可以通过约束网络图清晰地表达 ,这样设计问题就成为一个约束求解问题 ,本文在分析了约束求解的研究现状和不足的基础上 ,提出了一种基于动约束的约束求解方法     

并行设计中基于约束的产品评价方法研究

设计过程就是满足约束的过程。在并行设计中,需要考虑来自产品全生命周期中的各种约束。根据这种思想,提出了基于约束的产品评价方法。文中研究了约束满意度和权重的表达,从而对并行设计的评价可根据设计过程中涉及到的约束的满意程度的合成来实现。在此基础上,提出了一种基于约束的产品综合评价方法。最后,给出了基于约束的评价系统的结构和工作原理。     

Developing an Integrated Intelligent Framework to Support an Engineering Change Process for an Axial Piston Pump

Since the concepts of concurrent engineering were introduced in mid 1980s, the product design process has become complicated. This is because many factors related to the life cycle of the product may need to be considered during the design stage. Therefore, shortening product development time becomes important for the survival of an enterprise. In this paper, an integrated intelligent environment to support concurrent engineering is proposed. Two major modules are provided by this system to assist change management. One is a constraint network module that analyses the related constraints about a design change to find the design variables influenced. Another is a product assembly module that extracts the design data from a CAD database to analyse the spatial relationships relating to an assembly. The data in the above two modules are integrated in a data integrated module, in which an entity relational data model was developed to describe the integrated data. Finally, a web-based query system was developed to provide a multiplatform environment for the user to refer to the data in the constraint network module and the product assembly module during a design change process. The proposed environment is implemented in the design change process for an axial piston pump.     

Robust input design for nonlinear dynamic modeling of AUV

Input design has a dominant role in developing the dynamic model of autonomous underwater vehicles (AUVs) through system identification. Optimal input design is the process of generating informative inputs that can be used to generate the good quality dynamic model of AUVs. In a problem with optimal input design, the desired input signal depends on the unknown system which is intended to be identified. In this paper, the input design approach which is robust to uncertainties in model parameters is used. The Bayesian robust design strategy is applied to design input signals for dynamic modeling of AUVs. The employed approach can design multiple inputs and apply constraints on an AUV system’s inputs and outputs. Particle swarm optimization (PSO) is employed to solve the constraint robust optimization problem. The presented algorithm is used for designing the input signals for an AUV, and the estimate obtained by robust input design is compared with that of the optimal input design. According to the results, proposed input design can satisfy both robustness of constraints and optimality.     

基于约束网络的柔性装配系统建模方法研究

提出用约束网络方法对机器人柔性装配系统进行建模,该建模方法用变量描述装配对象与装配工艺、系统结构的约束关系,改变了传统装配系统的串行设计模式,该方法具有灵活性、易于修改和多向性,能较好地利用并行工程概念对系统进行设计。     

基于BP神经网络的齿轮约束性设计研究

针对变速传动工况对齿轮设计的要求,提出了针对不同约束性要求的齿轮设计知识约束驱动检索方法,并采用BP神经网络实现了对该方法的具体执行过程,分6种不同情况完成了对齿轮约束性设计的求解分析。研究过程以变速传动装置的运动传递功能实现为对象,讨论了BP网络的构造和训练样本的建设。研究结果表明,基于BP神经网络的齿轮约束性设计能够较为快速和准确地获得特定约束条件下的齿轮设计方案或者选型,提出神经网络BP算法能够实现约束与知识之间复杂、非线性映射关系。     

3D geometric constraint solving using the method of kinematic analysis

In this paper, an approach based on kinematic method for solving 3D geometric assembly constraints is presented. The relative generalized coordinates and generalized recursive formulations used in kinematic analysis are utilized to reduce the size of constraint equations. Based on the cut-constraint method, this approach can be used to solve all kinds of configurations. In the case of an open-loop constraint system, the geometric constraints can be satisfied by sequentially determining the values of relative generalized coordinates. With respect to a closed-loop constraint system, the proposed approach converts it to a spanning tree structure by cutting constraints and introducing cut-constraint equations. Furthermore, a topological analysis method is also developed to obtain the spanning tree with the minimal number of cut-constraint equations, and the analytical Jacobian matrix of cut-constraint equations is derived to enhance computational efficiency. In the end, the proposed approach is demonstrated and validated using two examples of closed-loop geometric constraint system.     

RESEARCH ON THE CONSTRAINT MAPPING FROM FUNCTION TO ASSEMBLY

Assembly sketch is not only the visualization of abstract function, but also the template of detail design. Two kinds of information are needed to create assembly sketch: structure and assembly constraint. Most researches are aimed at how to obtain structures from function, but the problem of how to obtain assembly constraint from function is ignored. Following the definition of assembly unit and the classification of function, a hierarchical mapping method from function to assembly constraint is put forward, and the mapping method includes two steps. The first step is the mapping from function to assembly semantics which is assembly expression and accordant with engineer's design habit. The second one is the mapping from assembly semantics to basic assembly constraints that are convenient for computer to handle. The mapping method is applied to DDMS (design, drafting and management system) successfully.     

面向CAD系统的设计知识表达与求解

通过分析现有参数化 CAD系统在知识表达方面不足的 ,提出了几类新的知识表示方法 ,并用一种基于约束网络的技术 ,实现了知识约束的智能化求解。集成了该功能的 CAD系统能有效地支持基于知识的产品参数化建模