面向拆卸的装配序列规划算法的实现

从装配模型中获取几何信息和配合关系 ,充分利用这些信息 ,引入优先拆卸方向的概念 ,通过局部配合约束表和干涉表的搜索 ,获得符合要求的装配序列。     

Constraint ratio in product assembly planning

Assembly planning considers the product, process, and production system. The existence of constraints makes the assembly planning process difficult and time consuming. The planning degree of freedom (PDOF) for designers will be increased if the number of constraints is decreased on either the product or the other sides. A higher PDOF means that companies can be more flexible in responding rapidly to the assembly of parts. In this paper, a constraint ratio (C_R) has been defined to measure the influence of the product constraints on assembly planning. Some rules have been established to simplify the evaluation procedures of the constraint ratio of the product. Examples are illustrated and explained.     

机器人装配系统中精度对装配成功率的影响

利用《机器人装配系统的精度分析》一文中所得出的结果,并以ＳＲＸ－４型ＳＣＡＲＡ机器人对摩托车气门的装配为例,采用蒙特卡洛模拟法分析了装配系统精度对装配成功的影响,实验结果验证了所得结论的正确性。     

装配序列生成的有序二叉决策图技术研究

为提高装配序列规划求解效率,在图论割集法的基础上,引入有序二叉决策图描述装配关联图、装配操作、装配几何可行性和装配稳定性.利用装配优先约束关系,简化装配关联图,设计了基于符号有序二叉决策图技术的装配序列生成算法,分析了该算法的时间复杂度.在每一次割集分解之后,检验子装配体的几何可行性和稳定性,实现装配序列生成过程中状态空间的隐式表示和搜索.研究实例验证了基于符号有序二叉决策图技术的装配序列生成算法的可行性和有效性.     

机器人装配系统产品装配质量影响因素研究

装配是产品生产中占用大量成本的劳动密集型过程,装配质量对产品的性能有直接影响。装配过程本身具有随机性和不确定性,如果机器人装配系统对干扰和误差的适应能力不强,产品的装配质量会因各种因素的影响而大大降低。基于产品形成的设计和装配过程,本文对机器人装配系统产品装配质量的影响因素进行了系统分析,建立了产品装配质量的影响体系,为正确评价机器人装配系统的性能和产品的装配质量奠定了基础。     

汽车摇臂自动装配机结构设计

汽车摇臂自动装配机用于在汽车摇臂中自动装入节油片及液压挺柱。主要介绍该装配机的总体结构、运动控制方案及工作流程,并说明了关键部件的结构及工作原理。     

机械产品模型自动装配动画的研究与实现

对产品自动装配动画关键技术进行了讨论,分析现有的序列规划方案后采用交互式规划方法进行序列规划.在装配路径规划方面提出了基于A* 搜索算法的动态步长扩展算法,减少了扩展次数,提高了算法效率.并时整个装配过程用关键帧动画进行动态显示,最后给出了一个车架模型的装配动画工程实例.     

基于有向约束图的装配序列并行化方法研究

并行装配与串行装配相比可以缩短装配时间,提高装配效率。为了实现产品的并行装配,提出了基于有向约束图的装配序列并行化方法。定义了装配约束矩阵和零件约束度的数学模型来描述装配体在装配过程中各零件的干涉状态,建立了装配体的有向约束图描述零件间的约束关系,给出了基于关联解除的有向约束图分解方法生成装配序列,采用装配序列并行化策略产生了基于多叉树结构的并行装配序列。通过机用虎钳装配实例验证结果表明了该方法的可行性。     

RETRACTED ARTICLE: Automatic micropart assembly of 3-Dimensional structure by vision based control

We propose a vision control strategy to perform automatic microassembly tasks in three-dimension (3-D) and develop relevant control software: specifically, using a 6 degree-of-freedom (DOF) robotic workstation to control a passive microgripper to automatically grasp a designated micropart from the chip, pivot the micropart, and then move the micropart to be vertically inserted into a designated slot on the chip. In the proposed control strategy, the whole microassembly task is divided into two subtasks, micro-grasping and micro-joining, in sequence. To guarantee the success of microassembly and manipulation accuracy, two different two-stage feedback motion strategies, the pattern matching and auto-focus method are employed, with the use of vision-based control system and the vision control software developed. Experiments conducted demonstrate the efficiency and validity of the proposed control strategy. This paper was recommended for publication in revised form by Associate Editor Dong Hwan Kim Lidai Wang received the B.A. Sc. and M.A.Sc. degree in instrument science and technology from the Tsinghua University, Beijing, China, in 2003 and 2005, respectively. He is currently working toward the Ph.D. degree in mechanical engineering at the University of Toronto, ON, Canada. His research interests include data fusion, computer vision, robotics, micromachines and control. His M.A.Sc. work involved the development of an inertial measurement unit and data fusion algorithm for use in miniature aerial vehicle. His current research specializes in the automation of robotic microassembly and its application. Seungmin Kim graduated with Bachelor’s degree in Mechanical Engineering (1992), Master’s degree in Mechanical Engineering (1996) and completed the Ph.D. degree in Mechanical Engineering (2005) from the Pukyung National University, Pusan, Korea, specializing in control system design. His research interests have encompassed a number of related areas, including: robotics and automation, motion controls, and mechatronics, design and control of high speed machines, MEMS 3D assembly, MEMS robotic task execution, etc. He works as a post-doctoral researcher at the University of Toronto in Canada from January 2008. Since 2005, he has been with the Mechatronics Examination Team at the Korea Intellectual Property Office, and is now an Assistant Director.     

Automatic assembly task of electric line using 6-link electro-hydraulic manipulators

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today’s highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulator because hydraulic manipulators have the advantage of electric insulation. Meanwhile it is relatively difficult to realize autonomous assembly tasks particularly in the case of manipulating flexible objects such as electric lines. In this report, a discrete event control system is introduced for automatic assembly task of electric lines into sleeves as one of the typical task of active electric power lines. In the implementation of a discrete event control system, LVQNN (linear vector quantization neural network) is applied to the insertion task of electric lines to sleeves. In order to apply these proposed control system to the unknown environment, virtual learning data for LVQNN is generated by fuzzy inference. By the experimental results of two types of electric lines and sleeves, these proposed discrete event control and neural network learning algorithm are confirmed very effective to the insertion tasks of electric lines to sleeves as a typical task of active electric power maintenance tasks.     

轿车前大灯装配结构的自适应偏差补偿方法研究

分析现有大灯尺寸配合的现状,从缩短尺寸链的角度提出针对大灯定位结构进行设计优化。重点研究三个问题:(1)现有尺寸链模型分析;(2)关键因素的识别及其工艺结构的改进;(3)从理论计算和实践两方面进行验证。基于自适应偏差补偿思想使用工装夹具进行装配工艺优化。并解决由此带来的刚性零件的过定位约束力释放的问题。用实车测量数据的对比形式验证该方法。     

A systematic method of adaptive joint design considering different assembly sequence in sheet metal product

In sheet metal assembly, not only the component variations and tool errors, but also the component structure (joint type) and assembly process (assembly sequence) affect the final dimensional quality. In this paper, a systematic method for adaptive joint design considering different assembly sequence is proposed to meet the in-process dimensional adjustability of KCs (key characteristics). First, the adaptive characteristic of the sheet metal joint is depicted. Then, the mathematical model in order for concurrently optimizing both joint type and different assembly sequence is presented. How to evaluate the combination of joint type and assembly sequence is carried out according to two conditions: (1) for single KC, and (2) for multiple KCs. The KC confliction is considered to ensure the important KCs. Genetic algorithm is used to resolve the optimization of joint design. An example is chosen to demonstrate our method finally, and various joint designs are acquired according to different assembly sequences by this means. The proposed methods make it possible for us to improve the dimensional quality of product in the design stage.     

复杂产品装配关系矩阵自动生成方法

针对现有装配关系模型在结构完备性、获取复杂性等方面的不足,研究了装配关系模型重构和装配关系信息自动获取方法。提出接触-连接矩阵,用以集成功能件和连接件间的接触关系和各类连接关系,并研究了利用静态间隙分析和工程语义解析来获取接触-连接矩阵的方法。提出扩展干涉矩阵,以解决现有干涉矩阵无法有效处理倾斜方向装配的问题,支持装配方向的优化求解,并研究了基于包围盒扫描和步进检测生成扩展干涉矩阵的方法。以UG为平台,开发了原型系统,并以具有非标准轴向装配的夹具为例,验证了该方法的有效性。     

集成环境下基于割集的装配顺序生成算法研究

在分析总结以往学者对装配顺序规划研究的基础上,综合拆卸法和优先约束法的特点,探讨了一种新的装配顺序分析方法,该方法利用产品的装配域信息,根据图论的割集法对产品进行拆分,建立几何优先约束关系,然后通过人机交互的方式建立工艺优先约束关系,最终得到可行的产品装配顺序。实现了集成环境下基于割集的装配顺序规划。给出了割集的生成算法框图以及装配顺序规划的算法框图,最后通过实例验证。     

基于UG的三维装配尺寸面链表组自动生成方法研究

针对目前装配尺寸链不能实现真正意义上的自动生成及在装配尺寸链中很少考虑几何要素的几何公差的问题,提出了一种基于几何要素控制点理论公差表示模型的三维装配尺寸面链表组自动生成方法。在分析装配公差建模的信息组成的基础上,建立了装配公差信息的计算机储存储数据混合图结构。以UG NX7.5为二次开发平台,提取了三维装配体内零件上尺寸公差、几何公差、装配基准以及装配目标等信息。首先,确定了封闭环;然后,根据建立装配尺寸链的最短路径的原则搜索装配公差信息图,建立了三维装配尺寸面链表;最后,根据装配顺序及设计基准将其按零件拆分为三维装配尺寸面链表组。以三正交平面作为装配基准的轴孔装配为例,对该方法进行了验证。研究结果表明,该方法能够综合考虑几何要素的尺寸和几何公差,为后续的公差分析工作打下坚实的基础。