装配规划与方案评价集成系统的研究与开发

为了将装配顺序规划与方案评价有效集成,规划合理的装配顺序,检验装配过程中存在的干涉情况,提出了人机交互定义分层装配顺序主模型与自动生成子装配的两级装配顺序规划方法．该方法适用于大型装配模型的装配顺序规划场合;在原有的研究项目KMCAD3D基础之上,开发了一套实用的装配顺序规划与方案评价原型系统;通过对二级蜗轮减速器实例的装配顺序规划讨论,说明了该方法的可行性．     

面向装配工序交叉的虚拟装配工艺信息模型

虚拟装配工艺规划中目前大都采用装配顺序描述装配过程,但尚无法表达装配工序交叉和设计中的安装布置'捌整等问题.考虑设计阶段和制造阶段的装配要求,建立了基于装配任务的装配工艺信息模型.该模型以多层次的装配进程表达产品装配工艺过程,通过任务对象的交叉安装表达工序交叉和安装布置凋整,并给出了装配调整策略;针对冗余装配任务提出了装配任务合并方法.最后通过实例验证了文中模型的正确性和有效性.     

基于PC机的虚拟装配的研究与实现

结合某高校PC机在组装过程中遇到的实际问题,开发了一套基于PC机的虚拟装配系统,提出了虚拟装配系统功能,对虚拟装配若干技术一算法、建模技术、控制按钮设计技术等进行了研究并给出了解决方案.在系统界面的设计中,讨论了主页面的划分及各个框架的作用.提出的理论和算法可应用到远程培训的教学活动中.     

基于规则和爆炸图的装配序列规划

提出局部爆炸图的概念，运用几何干涉规则生成各直角坐标方向的局部爆炸图；在确立各方向的合并顺序后，用合并规则生成各零件的合并约束前元集；并据此进行局部爆炸图合并求解装配序列，实现了规则推理和几何推理算法的紧密结合，有效地避免了装配序列组合爆炸，降低了装配规划的计算复杂度，保证规划所得装配序列的可行性和实用性．     

一个机器人柔性装配规划系统

柔性装配及其装配顺序是近年来在计算机辅助制造和计算机集成制造系统方面一个十分重要的研究领域.在知识表示和专家系统技术的基础上.本文首先简述了几种装配顺序的表示方法,然后提出一个基于知识的柔性装配规划系统的原型及其典型机构装配顺序的计算机模拟.本文所提出的方法,可以推广至更复杂的装配工作,并且为CAM和CIMS的控制和编程提出新的要求.     

一种带约束条件的关联规则频繁集挖掘

论文先提出顺序单调约束和反顺序单调约束的概念并对其所包含的数学性质进行了讨论,在此基础上将其运用于频繁集挖掘过程中,给出挖掘基于顺序反单调性约束的频繁集算法和挖掘基于顺序单调约束的频繁集算法。带约束条件的关联规则频繁集挖掘可减少生成无意义的规则;同时,在频繁集生成过程,利用约束条件对搜索空间进行修剪,可提高挖掘算法的效率。     

一种基于配合约束的装配顺序产生算法

结合配合约束在装配中的应用,在分析装配零件的配合约束及其特点的基础上,得到零件之间的空间位置关系和零件的局部自由度,充分利用这些信息,引入优先装配方向和局部自由度表的概念,提出了一种基于最少装配方向的装配顺序自动生成算法。     

基于规则的装配顺序规划方法研究

本文首先分析了将产品中各级零部件的层次结构关系和装配约束关系紧密结合为一体的产品装配结构树模型(Product Assembly Structural Model Tree),并在此基础上提出了一套基于规则的面向装配设计的产品装配顺序规划方法。     

基于规则的装配顺序规划方法研究

本文首先分析了将产品中各级零部件的层次结构关系和装配约束关系紧密结合为一体的产品装配结构树模型（Product Assembly Structural Model Tree)，并在此基础上提出了一套基于规则的面向装配设计的产品装配顺序规划方法。     

有卸货顺序约束的集装箱装载问题及算法研究

对有卸货顺序约束的三维集装箱问题进行了描述.基于禁忌规则,采用了求解该问题的模拟退火算法,设计了货物的摆放规则和序列生成方式.采用3种邻域,根据邻域的不同,构造了2种禁忌表.根据问题的特点,在模拟退火算法抽样过程中加入了禁忌规则.介绍了算法的原理,给出了具有代表性算例试验结果并且进行了分析.试验结果表明,提出的混合算法对有卸货顺序约束的集装箱三维装载问题的有效性.     

Tool selection-embedded optimal assembly planning in a dynamic manufacturing environment

This paper presents an approach for tool selection-embedded optimal assembly planning in dynamic manufacturing environments. It aims to embed assembly tools into the planning process of assembly sequences in a dynamic shop-floor. The experimental results demonstrate that the developed approach is efficient and practical for a high fidelity assembly sequence with alternatives of assembly-tool sets. The dynamic assembly planning can efficiently support product assembly by generating feasible assembly sequences. It provides an effective design-aiding tool to virtually deal with various what-if scenarios regarding product assembly. In particular, the Web-based application developed in this research can be incorporated into a high-performance design and manufacturing environment on the Web, forming a distributed, collaborative and globally networked tool for product assembly planning.     

虚拟装配仿真系统相关技术的研究

研究了一种等离子体增强化学气相沉积(PECVD)装备虚拟装配仿真系统,介绍了系统的装配模型以及装配顺序和路径的规划.建立了虚拟装配仿真场景结构图,并采用细节层次技术对仿真场景进行优化.为了能够实时、方便地修改装配序列和装配路径,准确地描述零部件在装配或拆卸过程中的位置姿态信息,提出了一种虚拟装配的描述语言代码(V代码)和虚拟装配函数(V函数).最后采用基于包围盒逐层分解的干涉检验方法,实现装配过程的干涉检验.该仿真系统有助于缩短产品开发周期、提高设计质量、降低装配成本.     

A physically based approach with human–machine cooperation concept to generate assembly sequences

Assembly plan is considered one of the important stages to minimize the cost of manufacturer and to ensure the safety of assembly operation, the main problem of assembly sequence planning approach is how to reduce the deviation from the real manufacture conditions. In this paper, we have extensively investigated a novel approach to automatically generate the assembly sequences for industrial field, which is especially applied to other large-scale structures. A physically based assembly representation model includes not only the pre-determined basic assembly information, such as precedence relations between parts or subassemblies, geometric constraints, different assembly types, and also the dynamic real-time physical properties, such as the center position of gravity, the force strength of the part, et al. This representation model considered the influences on optimum sequences by assembly operations will be modified by the feedback from interactive virtual environment. Then, we select the safety, efficiency and complexity as the optimization objectives. A hybrid search approach may be used to find the optimum assembly sequence, which will be integrated into an interactive assembly virtual environment (IAVE). It means that the results of assembly interaction can be provided to update the assembly planning model as a feedback, by which the approach will take advantages of the immune memory for local optimum search. The user can adjust the assembly sequences with obvious good objective by interaction with IAVE to improve the performance of the search algorithm. We describe human–machine cooperation (HMC) method for ASP in this work, by which human also can play a pivotal role instead of pure soft-computing. A series of numerical experiments are done to validate the performance of the physically based approach (PBA) to generate assembly sequence, which shows the efficiency and the operability to guide the assembly work.     

Assembly sequence planning based on structure cells in open design

Advances in computer network technologies have enabled firms to increasingly utilize external resources to remain competitive. Based on the function-behavior-structure cell (FBSC) modeling and computer network technologies, consumers with design knowledge and experience, called co-designers in this research, can involve in the process of open design (OD) to share their requirements, experiences and knowledge. The structure cells (SCs) provided by the co-designers in OD and the relationships among them are critical for generating the optimal design scheme and assembly sequence planning. However, the existing assembly sequence planning (ASP) approaches mainly focus on identification of the assembly plan based on precedence relations of operations from the predefined parts in the design scheme without considering the utilization of resources available in OD. In this study, a new approach for ASP based on SCs in OD is proposed to tackle this problem. First, the assembly features of the SCs and their matching rules are described in OD, and an approach for calculating the matching intensity between SCs is developed for identifying the assembly relationships between SCs. The design scheme is generated according to the SCs and their assembly relationships. Second, the base part of the design scheme is determined by its correlation degree with other parts. The feasible assembly sequences are derived by reversing the disassembly sequences. As the increase of the number of parts in design scheme will result in the combinatorial explosion of feasible assembly sequences, a particle swarm optimization algorithm is presented to achieve the optimal assembly sequence. A case study is provided to demonstrate the feasibility and effectiveness of the proposed approach.     

Development of a virtual and physical work cell to assemble micro-devices

The term ‘micro-assembly’ is used to describe the assembly of micron-sized parts that are extremely small (in the order of 10⁻⁶ m). As manual assembly of micro-devices is extremely difficult and tedious, there is a need to design computer-controlled approaches to facilitate rapid assembly. In this context, the design of automated or semi-automated environments for micro-assembly applications becomes important. In this paper, the design of a micro-assembly cell is discussed along with the development of a virtual assembly environment to study micro-assembly problems and issues. A genetic algorithm-based assembly sequence generator is discussed which works in coordination with a 3D path planning approach. A physical micro-assembly cell has been created to aid in the assembly of such micro-devices. This physical cell is interfaced with a virtual reality (VR)-based assembly environment to assist in the micro-assembly activities and comprises of micro-positioners, a micro-gripper (for pick-and-place operations to complete specific micro-assembly tasks), and a camera (to provide guidance and feedback during and after assembly).     

A systematic optimization approach for assembly sequence planning using Taguchi method, DOE, and BPNN

Research in assembly planning can be categorised into three types of approach: graph-based, knowledge-based and artificial intelligence approaches. The main drawbacks of the above approaches are as follows: the first is time-consuming; in the second approach it is difficult to find the optimal solution; and the third approach requires a high computing efficiency. To tackle these problems, this study develops a novel approach integrated with some graph-based heuristic working rules, robust back-propagation neural network (BPNN) engines via Taguchi method and design of experiment (DOE), and a knowledge-based engineering (KBE) system to assist the assembly engineers in promptly predicting a near-optimal assembly sequence. Three real-world examples are dedicated to evaluating the feasibility of the proposed model in terms of the differences in assembly sequences. The results show that the proposed model can efficiently generate BPNN engines, facilitate assembly sequence optimisation and allow the designers to recognise the contact relationships, assembly difficulties and assembly constraints of three-dimensional (3D) components in a virtual environment type.     

Using requirement-functional-logical-physical models to support early assembly process planning for complex aircraft systems integration

The assembly line process planning connects product design and manufacturing through translating design information to assembly integration sequence. The assembly integration sequence defines the aircraft system components installation and test precedence of an assembly process. This activity is part of the complex systems integration and verification process from a systems engineering view. In this paper, the complexity of modern aircraft is defined by classifying aircraft system interactions in terms of energy flow, information data, control signals and physical connections. At the early conceptual design phase of assembly line planning, the priority task is to understand these product complexities, and generate the installation and test sequence that satisfies the designed system function and meet design requirements. This research proposes a novel method for initial assembly process planning that accounts for both physical and functional integrations. The method defines aircraft system interactions by using systems engineering concepts based on traceable RFLP (Requirement, Functional, Logical and Physical) models and generate the assembly integration sequence through a structured approach. The proposed method is implemented in an industrial software environment, and tested in a case study. The result shows the feasibility and potential benefits of the proposed method.