基于约束关系的装配规划

本文为柔性装配系统(FAS)或机器人装配单元提出一种新的装配规划表示方法,它是在用有向无环图表示装配操作约束关系的基础上,用树结构来表示装配规划的表示方法。本文给出表示方法的形式化描述和在此表示上的线性装配规划的生成算法。     

使用机器视觉的柔性机器人装配质量控制

柔性机器人装配系统在现代制造系统中已越来越重要，装配质量控制是柔性机器人装配系统中的关键技术之一，装本质量控制的主要任务是检测装配状态的正确性并采取相应的措施施保证装配质量，本文提出了柔性机器人装配控制的模型以及实现这个模型的一些有效方法，最后给出一实例。     

机器人化柔性装配过程的模糊自动机模型

机器人化柔性装配系统是现代制造系统的重要研究内容之一．装配过程的建模是许多研究工作的基础．本文在分析装配过程的特点的基础上，将模糊自动机的理论和方法应用于装配过程的建模研究中，提出了一种机器人化柔性装配过程的模糊自动机模型     

浅谈当代计算机辅助装配的发展方向

装配是产品实现主要功能的重要过程,装配规划直接影响着产品的质量以及成本,是完美实现装配的重要环节。计算机辅助装配的规划涉及技术领域众多,是计算机集成制造中的关键技术,本文主要通过对目前计算机辅助装配规划以及装配顺序的研究,来对以后计算机辅助装配的发展方向进行了分析。     

面向并行设计的装配顺序规划研究

该文根据先进制造发展的特点,结合现代设计理论提出了适合敏捷制造的面向并行设计的装配顺序规划系统结构.针对在自动装配顺序规划过程中没有实际接触零件之间相互干涉这一难点问题,应用了虚接触原理,并给出了相应的虚接触生成规则.为了使设计人员和用户更有效地获得装配信息,提出了信息反馈规则.文中结合例子讨论了虚接触和信息反馈在生成可行装配顺序推理过程中的应用,证明了其可行性和有效性.最后讨论了在虚拟现实环境中进行装配仿真的优势和意义.     

基于配合特征的机械装配自动规划

本文根据机械装配配合特征确定装配操作优先顺序,并设计了相应的算法。提出利用布尔矢量表示装配优先顺序,利用图的拓扑排序实现装配任务的自动规划。     

复杂机电产品中的柔性线缆装配过程仿真技术

针对复杂机电产品中柔性线缆结构复杂且在装配操作中发生变形而导致的装配过程仿真难的问题,系统地提出了柔性线缆装配过程仿真的解决方案及其关键技术的实现方法.首先提出一种基于元素包含关系和无向图的线缆数字化表达模型,实现了复杂线缆拓扑、几何和属性信息的统一表达,为装配过程仿真奠定了基础;然后提出一种改进的层次链装配过程模型,统一处理针对不同对象的装配任务和装配操作等,实现了装配过程中线缆和结构件交叉装配任务和装配操作的表达和存储;最后建立一种改进的线缆质点-弹簧模型,通过添加长度变化约束并设定典型装配操作中的约束条件,实现了线缆在装配仿真中柔性形变的实时仿真.在开发的原型系统中实现了柔性线缆的装配过程仿真,并通过实例验证了文中方法的可行性.     

车身设计尺寸质量评价的装配尺寸链自动生成

提出一种适合计算机推演的车身尺寸链生成方法．在研究装配有向图表达基础上建立车身装配接触链模型,并应用图论方法开发了以关键尺寸为目标的路径搜索算法;通过可行路径和尺寸链的映射关系,生成车身装配尺寸链．该方法的实现,有助于建立计算机辅助的车身柔性件尺寸质量评价系统。     

面向装配序列规划的装配本体设计*

为提高装配序列规划的自动化程度,实现装配相关活动间信息的共享、重用和顺畅传递,实现装配序列规划系统与其它异构系统之间的无缝集成和互操作,将本体技术引入到装配建模中.针对装配序列规划建模需求,构建面向装配序列规划且基于装配对象的装配本体(OWL-ASP).OWL-ASP由Properties本体、AssemblyInfo本体和AssemblySeq本体组成,分别描述装配对象的装配属性、装配信息、装配顺序等.在OWL-ASP的基础上,利用语义Web规则语言刻画装配规则,形成统一的装配知识表示层次体系,实现对装配知识的严格刻画和自动推理.通过球阀装配的实例说明装配本体和装配规则的有效性.     

基于接触状态感知发育的机器人柔性装配方法

为了提高工业机器人装配的实时性、自适应性和鲁棒性,借鉴人类后天感知学习方式,提出一种基于接触状态感知发育的柔性装配方法.采用机器人末端的位姿和力/力矩来描述装配接触状态,结合支持向量数据描述和改进极限学习机对接触状态感知发育,形成可自我更新成长的经验知识库,预测机器人的装配动作,完成柔性装配任务.为验证所提出方法的有效性,以小型断路器卡合装配为例进行实验,实验结果表明,采用接触状态感知发育可实现装配经验知识库的自我更新,完成机器人的柔性装配,验证了所提出方法的可行性和有效性.     

基于分层强化学习的通用装配序列规划算法

对于装配序列规划问题,现有算法大多聚焦于单一的目标构型.对于多目标构型以及大规模问题,现有算法往往存在维数灾难及泛化能力差等问题.为此,利用装配序列规划问题分层结构的特点,提出一种基于分层强化学习的适用于多构型装配任务的通用装配序列规划方法.首先,将装配序列规划问题构建为一个分层的马尔科夫决策过程,其中,上层进行序列规划,下层进行零件的动作规划,符合装配过程层次化的结构,使规划方法更具灵活性,且可解释性更强;其次,针对分层马尔科夫决策过程,提出一种基于分层强化学习的通用装配序列规划算法,提高规划方法对多种目标构型任务的适应能力和泛化能力,以及对目标构型的信息利用率;最后,在搭建的仿真平台上进行验证,结果表明所提方法可以提取到关于装配问题的广义信息,对于不同零件初始位置以及其他多种构型装配任务均具有较好的决策能力,从而验证所提方法的有效性和通用性,表明该算法是适用于多目标构型的更加通用灵活的装配序列规划算法.     

具有相型寿命的Clarke型CIMS生产线可靠性研究

详细地研究了具有位相型寿命,带有两类不同柔性机制的有限缓冲库的Clarke型 CIMS生产线的可靠性问题.首先给出了各个工件广义加工时间相型结构的递变规律,其次 在平稳状态下利用二维标值闭环网络理论,给出了系统的主要稳态生产指标和可靠性指标的 算法公式.最后讨论了系统对参数组摄动时的灵敏界.     

Assembly sequence planning of rigid and flexible parts

Assembly sequence planning (ASP) is the process of computing a sequence of assembly motions for constituent parts of an assembled final product. ASP is proven to be NP-hard and thus its effective and efficient solution has been a challenge for the researchers in the field. Despite the fact that most assembled products like ships, aircrafts and automobiles are composed of rigid and flexible parts, no work exists for assembly/disassembly sequence planning of flexible parts. This paper lays out a theoretical ground for modeling the deformability of flexible assembly parts by introducing the concept of Assembly stress matrix (ASM) to describe interference relations between parts of an assembly and the amount of compressive stress needed for assembling flexible parts. Also, the Scatter Search (SS) optimization algorithm is customized for this problem to produce high-quality solutions by simultaneously minimizing both the maximum applied stress exerted for performing assembly operations and the number of assembly direction changes. The parameters of this algorithm are tuned by a TOPSIS-Taguchi based tuning method. A number of ASP problems with rigid and flexible parts were solved by the presented SS and other algorithms like Genetic and Memetic algorithms, Simulated Annealing, Breakout Local Search, Iterated Local Search, and Multistart Local Search, and the results and their in-depth statistical analyses showed that the SS outperformed other algorithms by producing the best-known or optimal solutions with highest success rates.     

面向对象CIMS体系结构在制浆造纸中的应用

介绍了制浆造纸工业的特点及其对CIMS的需求,分析了CIMS的研究现状,提出了面向对象的CIMS体系结构及其在制浆造纸工业上的应用,并对其核心技术和新技术进行了详细介绍,最后介绍了面向对象的CIMS体系结构的特点。     

Integrated knowledge-based Petri net intelligent flexible assembly planning

Automatic assembly planning is recognized as an important tool for reducing manufacturing costs in concurrent product and process development. A novel knowledge-based Petri net (KBPN) is defined, based on the incorporation of expert systems into the usual Petri nets, and used for a unified assembly knowledge representation scheme. A KBPN-approach integrated with a sequence generation algorithm is proposed for the modeling, planning, simulation, analysis and evaluation of the flexible assembly system (FAS). The developed KBPN-based assembly planning system (KAPS) can automatically adjust the deviations between the theoretical planning parameters and the process parameters of real assembly operations to guarantee the best strategies and plans (sequences) for flexible assembly. The research findings are exemplified with a simple assembly to show the effectiveness of the method.     

Assembly sequence and path planning for monotone and nonmonotone assemblies with rigid and flexible parts

The Assembly Sequence and Path Planning (ASPP) problem deals with finding a proper sequence of parts to be assembled into a finished product and short assembly paths for each part. The problem is a combination of Assembly Sequence Planning (ASP) and Assembly Path Planning (APP) subproblems, which are both NP-complete and therefore intractable at large sizes. Nearly in all works on ASPP, it is assumed that planning is monotone (i.e., parts are moved only once, without considering intermediate placements) and each part is completely rigid. These are simplifying, yet limiting assumptions, since most assembled products like ships, aircraft, and automobiles are composed of rigid and flexible parts, and the generation of assembly sequence and path plans for most real-world products requires intermediate placement of parts to be taken into account. None of the existing works in the literature, however, have handled nonmonotone ASPP problems for rigid and flexible parts, and this issue remains largely untouched. In this paper, we present a new method called SPP-Flex for solving monotone and nonmonotone ASPP for rigid and flexible parts. SPP-Flex first utilizes a Directional Assembly Stress Matrix (DASM) for describing interference relations between all pairs of parts and the amounts of compressive stresses needed for assembling flexible parts and then obtains an initial tentative assembly sequence using a simple new greedy heuristic. Next, short assembly paths are iteratively computed and planned from initial to goal configurations of all parts using a novel sampling-based path planner called BXXT. If finding a free path for an active part fails due to obstruction of a previously assembled part, then such a part is identified, relocated, and its path replanned until the active part is moved to its final position. In case of failure again, if the part is flexible, through finite element analysis, it is determined if the part can still be assembled by undergoing elastic deformation. To evaluate the performance of the SPP-Flex and its components, two new products were designed and solved by four combinations of ASP and APP methods 20 times each, and the means and standard deviations of five performance criteria (total path length, total number of generated nodes and edges in the search tree, total number of collision (interference) checks, and total runtime) were calculated. Analysis of the computational results showed that the proposed greedy heuristic sequence planner together with the BXXT path planner/replanner outperformed other variations with at most 4.6% average gap in path length and 2.1% average gap in runtime compared to the best-found solution in all runs.     

一个CIMS环境下的基于范例的船体装配CAPP系统

本文介绍了一个CIMS环境下的基于范例的船体 装配CAPP系统．包括：CAPP系统在渤海造船厂CIMS工程中的地位,基于范例的工艺规划（范 例的表达,范例的索引、存储、检索和适应）,工艺定额和材料定额制定,分系统之间的信 息集成．系统采用Power Builder 和 SQL Server 数据库中的SQL语言编写．目前,船体装 配CAPP系统已经在渤海造船厂的微机上连网运行．     

Assessment of the strategies for effective implementation of computer integrated manufacturing systems (CIMS)

There have been enormous amounts invested by manufacturing firms in the United States and elsewhere around the world in CIMS. Published reports of these CIMS implementations have shown mixed results, some failures and some notable successes. This paper provides an outline of an ongoing research which is expected to extract and synthesize the general implementation success factors delineated from past implementation efforts, and is expected to serve as a guide for future efforts to implement CIMS.     

非串行CIMS生产线可靠性建模、分析与综合

采用等效工作站方法,对非串行CIMS生产线可靠性进行了研究,得到了一条缓冲库可 用度的定理,并推导出在稳态情况下,非串行CIMS系统(如装配线和拆卸线)可以转变成串 行系统求解.同时分析出加工过程不丢失工件的充要条件和若干必要条件,绘出一幅PK-K 曲线,可以给出可行解的大致范围,有助于具体问题的求解.     

Who said robots should work like people?

Predictions made about the future of robotics have consistently proposed that the largest application area for robots in the 1990s would be automated assembly. To date, however, very few flexible systems for performing assembly tasks are in place and operating cost effectively on a regular basis. It has been assumed that assembly robots would be anthropomorphic in geometry and would operate on parts being conveyed through a factory much as people do. The advantages of the robot were to be its abilities to assemble varieties of products, to use sensed inputs to adapt to changes in the assembly process, and coupled with computers to bring a level of intelligence to the factory floor. Implicit was the assumption that they would be more cooperative than human laborers.