Automated rivet detection in the EOL image for aircraft lap joints inspection

An enhanced visual inspection technique named Edge of Light^TM (EOL) was invented and developed at the Institute for Aerospace Research, National Research Council Canada. One application is the detection and measurement of “pillowing” deformation caused by corrosion in the faying surfaces of riveted aircraft fuselage joints. To quantify the hidden corrosion products, one solution is to relate the average corrosion in a region to the peak-to-peak amplitude of the EOL image brightness profile between two diagonally adjacent rivet centers. This raises the requirement to automatically detect and locate the rivets in an EOL image. The variation in illumination over individual rivets degrades the performance of most of the edge detection algorithms. In this study, a phase congruency algorithm is employed to provide an absolute measurement of EOL image features. The detected feature together with the knowledge of rivet size and the number of rows are used to locate rivets in the EOL image. The performance of the approach is compared with commonly used circle detection algorithms and an adaptive threshold approach. The efficiency of the proposed algorithm is assessed experimentally and the results are used in the quantitative evaluation of aircraft hidden corrosion.     

Selective Disassembly Sequencing: A Methodology for the Disassembly of End-of-Life Products

Disassembly planning has become an important strategic issue in order to reduce the environmental impact and increase the value of end-of-life (EOL) products. However, in order to make the recovery of EOL products viable, optimal disassembly sequencing has to be determined for each reusable component. In this paper, a selective disassembly methodology for EOL products is presented, which was developed by reversing and modifying the methodology developed by Nevins and Whitney (1989) for assembly. In the new methodology, the disassembly sequence generation and selective part recovery are largely performed by a special computer software. A number of product case studies were used to prove the concept and demonstrate the efficiency of the methodology.     

A WEB-BASED SYSTEM FOR REVERSE MANUFACTURING AND PRODUCT ENVIRONMENTAL IMPACT ASSESSMENT CONSIDERING END-OF-LIFE DISPOSITIONS

Widespread usage of electronic equipment and shortened product life cycles have challenged original equipment manufacturers (OEMs) to handle End-Of-Life (EOL) product through environmentally benign reverse manufacturing and reusable resources recovery. This paper presents a web-based decision support and evaluation system for operations in remanufacturing and recycling including electronic product disassembly, materials recovery, and recycling management. An overall evaluation of the product's lifecycle environmental impact considering EOL dispositions is also provided. The system has been tested by a major computer manufacturer with computer systems including desktop, laptop, and server. Comprehensive product analysis and environmental impact assessment are discussed in the paper.     

Mapping Knowledge about Product Lifecycle Engineering for Ontology Construction via Object-Process Methodology

Knowledge mapping is a first and mandatory step in ontology definition. This paper considers the lifecycle of products and systems, and discusses the creation of a knowledge-based ontology. With respect to the life cycle of products and systems, knowledge refers to the processes involved in their creation (design manufacturing and assembly), use and maintenance, and end of life (EOL). Hence, this knowledge should consider what a product is comprised of (its structure), how it operates (its dynamics), and how it interacts with the environment. A clearly defined and consistent mapping of knowledge regarding structure, operation and interaction is necessary to construct an effective and useful ontology. Yet, in order to obtain the required knowledge and to organize it in a consistent and useful form, an appropriate ontology must be used. An interactive, iterative and consistent method is needed to cope with this complex and circular problem. In this paper, the Object-Process Methodology (OPM) approach is considered, along with OPCAT [1], a tool for OPM-based knowledge modeling. OPM is a systems-modeling approach that represents knowledge about systems concurrently and bi-modally through graphics (a set of Object-Process Diagrams, OPDs) and text (Object-Process Language, OPL, a subset of English), yielding a single, unified and consistent view. In this paper we propose a foundational modeling and ontology construction approach for a generic product that incorporates hardware and software components. The ontology can serve as a basis for a knowledge model to cover the entire product lifecycle, from inception to EOL, and can be applied in the VRL-KCiP Network of Excellence.     

Comparative impact assessment for flax fibre versus conventional glass fibre reinforced composites: Are bio-based reinforcement materials the way to go?

In many applications the use of composite materials can offer significant weight reduction opportunities, which can have a positive influence on the life cycle impact of a component or system primarily through energy saving effects in the use phase. The impact associated with the production and end-of-life (EOL) phases, however, forms a possible counter indication for systematic replacement of conventional structures by composite solutions.     

Control of ultrafine microstructure by single-pass heavy deformation and cold forging of metal

A hot extrusion system with controlled cooling is investigated in this study. This system is used with the aim of manufacturing steel and other metal products with ultrafine microstructures by single-pass heavy deformation followed by controlled cooling. The continuous formation of bulk materials with the desired geometry and microstructure could be realized using the proposed system or by adding hot rolling stands after processing using the proposed system. Microstructure evolution during and after heavy single-pass deformation is examined through a series of experiments involving the hot extrusion of plain carbon steel followed by controlled cooling. The effects of severe plastic deformation on grain refinement and the mechanical properties of the formed products are discussed. It is clear that the use of the proposed system is helpful for the grain refinement of a cast microstructure. Also, ultrafine-grain steel with a grain diameter of 3 μm can be formed using the proposed system. Finally, the formability of the ultrafine-grain steel manufactured using the proposed system is examined by a cold-forging experiment.     

可重构数控系统设计与实现

文章提出了一种可重构数控系统设计方案。该方案采用了将数控系统控制单元、驱动单元等分别设计为独立的标准卡件式结构，通过总线联结，根据不同的应用需求，灵活地改变自身体系结构的设计方法。采用该技术方案设计的数控系统具有硬件普适性，通过更换处理器控制平台或配置不同的软件代码，即可实现不同设备的控制功能，从而减少硬件开发上的投入、缩短产品开发周期。     

DROF工艺中轧件头尾温差与组织性能均匀性控制

棒线材免加热直接轧制（DROF）工艺有一个难以避免的问题,即轧件头尾温差问题。当轧件头尾温差较大时,会对产品组织性能均匀性产生不利影响。本文讨论了由于轧件头尾温差带来的产品组织性能波动范围,分析了在铸坯切断、送到轧机入口处、上冷床等几个特殊时刻,轧件沿纵向的温度分布特点。为了解决轧件头尾温差问题,提出采用精轧机组前变水量冷却、粗轧机组前变功率感应补热、切坯台加变长度保温罩等3种方式,以有效减小免加热条件下轧件头尾温差,控制其组织性能差异,获得质量优良的产品。     

肯尼亚天然金红石矿流化床氯化率的研究

对肯尼亚金红石矿加碳氯化体系的热力学和动力学进行了研究,分析表明,C在固相中过量,体系处于平衡态时,TiCl4和CO是仅有的2个稳定的产物,增加C/TiO2比对产物组成影响不大;高温时,TiO2与C和Cl2生成CO的方程是占主导地位的。本实验提出了一个反应速率模型,得到金红石氯化率的公式,与实验数据吻合较好。反应速率与颗粒初始半径和天然金红石密度有关,在900℃到1000℃温度范围内,表观活化能为10.569 kJ/mol,扩散是反应的主要控制步骤。得到了C-Cl2体系中氯气反应率表达式,氯气反应率取决于反应程度、氯气浓度和焦炭粒径。     

双色脚套注塑模具设计

双色脚套在眼镜上的运用越来越广,但在制造过程中存在深孔成型难题。通过对双色脚套塑料制品的分析,提出制作双色脚套的打针式注塑模具结构:依靠插芯加热系统、滑动系统和动力系统来实现塑件深孔成型,并指出可实现该模具结构标准化。通过设计2套独立的注塑模,使双色注塑成为可能,解决了本厂缺少多色注塑设备的难题。生产实践证明:该模具结构合理可靠,保证了产品质量。     

工业CT机床精密运动的网络控制系统应用开发

文章针对工业CT机床所需要的精密运动控制作了的应用开发.研究了针对Kollmorgen精密运动产品的开发应用技术并实现.文中所提出的技术路线及实现方法已经得到实际应用.对于相关的工程技术及开发人员有一定的参考作用.     

热轧带钢卷取温度智能预报系统及仿真程序的研究

将先进的控制理论和智能优化算法应用于实际生产中,是进一步提高热轧带钢卷取温度控制精度的有效途径。在设计了“优生“和“返祖”两个新的遗传操作的基础上,提出了参数智能化设计的遗传算法,并将其应用于基于遗传神经网络的卷取温度预报系统;利用某钢厂热轧作业部的历史数据,对模型进行了有导师训练和离线测试;基于MFC(微软基类库)的仿真程序结果表明：该卷取温度预报系统预报精度高,且算法收敛速度快,不仅可以提高热轧带钢的产品质量,同时为发展高端、高附加值的带钢产品提供了有力的技术支持。     

Convertibility Measures for Manufacturing Systems

With increased consumer demands for a wider variety of products In changeable, unpredicted quantities, manufacturing system responsiveness has become increasingly Important for Industry competitiveness. Manufacturers need systems that can be rapidly adjusted with regard to both functionality and throughput capacity over the lifetime of the system. Convertibility is defined as the capability of a system to adjust production functionality, or change from one product to another. End-users of manufacturing systems are struggling with the Issue of how to measure and quantify convertibility. Metrics for convertibility are proposed in this paper so that different manufacturing systems can be compared with respect to this area of performance. These metrics are based on assessments of the configuration itself, and the system components such as machines and material handling devices. Metrics for quantifying convertibility are useful for comparing system configurations during the early phases of design, with out requiring detailed product or process plan Information.     

Conditions for cognitive self-organisation implied by visual-word processing

In order to find conditions for biologically plausible, cognitive self-organisation, an adequate representation of the final stage of this process is crucial. The implications of this assumption are analysed for the area of visual-word processing, in particular for position-specific top-down processes from a word – to a letter representation. These processes pose a problem to reviewed models of word reading and computational models in general. A solution in the form of a conceptual network is proposed. In this general model for cognitive brain processes, neural binding of identity and location and of identity and position play a fundamental role: temporary connections emerge during word recognition and are reactivated later, when a letter at given position has to be identified. It is shown how modules active in word recognition are “re-used” in letter identification. In simulations, the role of a critical threshold of cell-assemblies is shown and the selective propagation of activation loops at task-dependent time scales. Requirements for prospective studies on cognitive self-organisation and relations with new empirical work on visual-word processing are discussed.     

液-固挤压复合材料工艺参数的优化设计

提出了一种适宜于液-固挤压复合材料工艺系统的多目标优化模型．通过合理决策过程,将多目标转化为单目标优化进行求解．在对编码规则、初始种群的产生、目标函数向适配值的转换以及种群数量、交叉概率、变异概率选择等问题进行深入研究的基础上,建立了基于遗传算法的液-固挤压复合材料优化系统．理论及实验研究表明可以获得较好的优化增益．采用优化设计参数进行实验,成形出质量良好的复合材料制件,且实现了变形力小、浸渗时间较短和浇注温度较低的预期目标,为该工艺的实际应用奠定了基础．     

模糊非线性积分滑模张力控制系统的研究

张力控制是诸多行业中卷绕系统的关键技术,直接影响着产品的质量。针对卷绕张力系统耦合性强,干扰因素较多等问题,提出了一种鲁棒性强的模糊非线性积分滑模控制方法。以伺服电机为张力执行机构对卷绕张力系统进行数学建模。提出双闭环控制方案并设计了模糊非线性积分滑模张力控制器和具有过渡过程的转矩PID控制器。在MATLAB/Simulink环境中建立了张力控制系统模型并进行了仿真验证。仿真结果表明张力控制系统具有启动过程快速稳定,抗干扰能力强等特点。     

多径成型因子在智能电网认知无线电信道干扰分析中的应用

针对认知无线电网络多用户并发通信尚未解决的信道干扰问题,在莱斯衰落信道下引入小尺度多径成型因子进行建模,系统地分析了认知用户对主用户传输的信道干扰。数值分析表明:多径成型因子理论能有效分析认知无线电网络主用户和认知用户的并发通信干扰行为,并在满足主用户服务质量(Quality of Service,Qo S)的需求上,动态地改变认知用户接入数目,提高了频谱资源的利用率。所提分析模型可以用于优化认知无线电技术在智能电网复杂场景中的应用性能。     

Autonomous Processes in Assembly Systems

Today's assembly systems have to be flexible to adapt quickly to an increasing number and variety of products and changing demand volume. To manage these dynamics, flexible, reconfigurable, and autonomous assembly systems were proposed and partly realised in the last two decades. The flexibility and adaptability is realised by clustering the assembly system into subsystems and modules which get a certain degree of autonomy and control themselves in a decentralised way. This keynote paper will present the general principles of autonomy and the proposed concepts, methods and technologies to realise autonomous processes in assembly systems. Different approaches for design and autonomous operation of assembly will be explained and future trends towards fully autonomous components of an assembly system as well as autonomous parts and products will be discussed.     

Development of an automated process sequence design system for multistage elliptical-Shaped deep drawing products

This study defined the cross-section consisting of a round in the major axis and a straight line in the minor axis for deep drawing product as elliptical. A process sequence design for elliptical-shaped deep drawing products was diversely proposed according to shape, dimension, and specification of products. This study presents two approaches to the design of a preform, a key process for elliptical-shaped products: using a punch with a circular cross-section, and for geometrical similarity of the intermediate process cup and final product, using a punch with a cross-section similar to that of the oval-shaped cup. In addition, blank shapes for elliptical-shaped products were designed and verified with experimental results. In the study, production rules, which play important roles in an automated process sequence design system, based on two approaches mentioned above and blank design, were generated for elliptical-shaped deep drawing products. The system developed on the production rules consists of a recognition module of input geometry, 3-D modeling to calculate surface area automatically, blank design, and a process planning module. Improving productivity and reducing time and cost would prove to be very useful.     

Active glass-type human augmented cognition system considering attention and intention

Human cognition is the result of an interaction of several complex cognitive processes with limited capabilities. Therefore, the primary objective of human cognitive augmentation is to assist and expand these limited human cognitive capabilities independently or together. In this study, we propose a glass-type human augmented cognition system, which attempts to actively assist human memory functions by providing relevant, necessary and intended information by constantly assessing intention of the user. To achieve this, we exploit selective attention and intention processes. Although the system can be used in various real-life scenarios, we test the performance of the system in a person identity scenario. To detect the intended face, the system analyses the gaze points and change in pupil size to determine the intention of the user. An assessment of the gaze points and change in pupil size together indicates that the user intends to know the identity and information about the person in question. Then, the system retrieves several clues through speech recognition system and retrieves relevant information about the face, which is finally displayed through head-mounted display. We present the performance of several components of the system. Our results show that the active and relevant assistance based on users' intention significantly helps the enhancement of memory functions.