Machining of micro-systems

An increasing trend towards miniaturization of mechanical components necessitates the further development of micro-machining techniques in order to produce components within given tolerances. For the dressing of multilayered, metallically bonded, fine-grained grinding wheels that are used for micro-grinding the technique of electro contact discharge dressing was developed. In the following, the determined interrelations between the variables dressing voltage, limitation of dressing current, infeed and feed of electrode, and the volume flow rate in conditioning as well as the quality factor in conditioning are presented and illustrated. Thanks to the development of new geometries of CVD-diamond micro-grinding-pencils, a reduction of edge disruptions as well as a reduction of tool diameters to a minimum of 250 μm for the machining of brittle materials could be achieved. For the micro-drilling of ductile materials the maximal drilling depth could be increased by means of an adjusted process control. The smallest examined drill diameter was 50 μm. The utilizability of the developed processes and tools was proven in the production of aerostatic micro-bearings in the scope of the collaborative research center (SFB) 516.     

并行微处理系统及其在实时控制中的应用

本文介绍了并行处理中广泛应用的Transputer系统及其对工业实时控制的适用性，并论述了实时控制的并行处理方法。     

Hybrid universal handling systems for micro component assembly

Highly sophisticated machining techniques make it possible to manufacture ultra precise micro components as small as 100 μm3. These micro components are normally mounted onto larger macroscopic components before being incorporated into, e.g., medical, telecommunication or sensor technology products. In view of the highly inflexible systems currently available, the work carried out by the Fraunhofer IPT with funding from the SFB 440 focuses on the development of a hybrid, universally applicable fine positioning system. The system consists of an assembly head which, with the aid of an integrated six-axis fine positioning unit and an integrated sensor unit for referencing the assembly position, gives a conventional positioning system such as an articulated robot arm the ability to perform highly precise micro assembly processes. This provides the context for the development work carried out by the Fraunhofer IPT into assembly head design concepts. The first step involved investigating the positioning behavior of a conventional articulated robot arm, and then analyzing the demands placed on the assembly head. This is followed by the development and optimization of the miniaturized guidance, actuator and sensor components that are needed for the construction of a robust, highly precise six-axis fine adjustment system. The result of this work includes a set of linear guides, the size of a matchbox, with air bearings. The prototype guides set up at the Fraunhofer IPT have a non-contact interface, which makes it possible to convey compressed air without friction or force.     

Biological cardio-micro-pumps for microbioreactors and analytical micro-systems

Bio-hybrid microsystems actuated by living cells, as micro-bio-actuators and micro-bio-pumps have been developed recently. In these devices biological cells may be powered without external energy sources and the movement or the contraction of muscle cells trigger off the flow of fluid (i.e. culture medium or blood) through microchannels in micro-multi-bioreactor systems. Isolated and in vitro cultured cardiomyocytes (cardiac cells) are the most promising bio-material, which can be used to design a micro-bio-pump/actuator. These spontaneously contracting cells are autonomously powered with glucose as an energy source without any external power supply or stimulus, unlike conventional micro-actuators/micro-pumps. Cardio-micro-bio-pumps/actuators are using collective, synchronous contracting forces of cardiac cells or cardiac cell sheets to drive the flow of fluid. The feasibility of building such actuators was demonstrated in a few examples of bio-hybrid microsystems actuated by single or sheeted cardiomyocytes.     

基于视觉引导的SCARA机器人自动装配系统

现有生产线工业机器人抓取点固定,工件只能以固定的姿态提前摆放在固定的位置,这种装配模式很难满足复杂的工业生产要求且效率低下。设计了基于视觉引导的机器人装配系统改进原有系统。设计了机器视觉系统,实现了工件的快速识别、定位以及姿态确定功能;设计了抓放系统,实现了工件的精确抓取和安装功能;采用Visual Studio的MFC开发,实现图像处理算法,并利用Socket通信将坐标和姿态数据发送给机器人。通过实验验证本系统具有良好的稳定性和快速性,可以满足生产的要求,大幅提高生产效率。     

装配线物料搬运的拉格朗日松弛算法

为提高汽车制造企业混流装配线的运行效益,提出了基于看板模型的多封闭循环路径多载量小车物料配送调度方法—–装配线物料配送调度的拉格朗日松弛算法.首先对问题域进行了描述并做出了具体假设,以最小化配送系统总成本为目标,建立了混合整数规划模型.在此基础上,针对该模型提出了两种算法—–次梯度和随机步长拉格朗日松弛算法,将松弛问题分解为两个决策子问题分别进行求解.仿真实验表明提出的两种调度算法均适用于该研究问题域,并在求解时间及稳定性上表现出良好的性能.     

Multi-label active learning by model guided distribution matching

Multi-label learning is an effective framework for learning with objects that have multiple semantic labels, and has been successfully applied into many real-world tasks. In contrast with traditional single-label learning, the cost of labeling a multi-label example is rather high, thus it becomes an important task to train an effectivemulti-label learning model with as few labeled examples as possible. Active learning, which actively selects the most valuable data to query their labels, is the most important approach to reduce labeling cost. In this paper, we propose a novel approach MADM for batch mode multi-label active learning. On one hand, MADM exploits representativeness and diversity in both the feature and label space by matching the distribution between labeled and unlabeled data. On the other hand, it tends to query predicted positive instances, which are expected to be more informative than negative ones. Experiments on benchmark datasets demonstrate that the proposed approach can reduce the labeling cost significantly.     

Optimal self assembly of modular manipulators with active and passive modules

In this paper, we develop self-assembling robot systems composed of active modular robots and passive bars. The target structure is modeled as a dynamic graph. We present two provably correct algorithms for creating the structure. A decentralized optimal algorithm for the navigation of multiple modular robots on a partial truss structure is used to guide the robots to their location on the target structure. A decentralized algorithm for scheduling the transportation and placement of truss elements is used to coordinate the creation of the target structure. Both algorithms rely on locally optimal matching. The truss self-assembly algorithm has quadratic competitive ratio for static as well as dynamic graph representation. We show simulation results and results for experiments with two 3DOF robots and passive bars that can create and control a 6DOF manipulation.     

A self-adjusting active compliance controller for multiple robots handling an object

This paper presents the concept and experimental validation of a self-adjusting active compliance controller for n robots handling its compliant behaviour concerning partly unknown flexible object. The control strategy is based on the decomposition of the 6n-dimensional position/force space and includes a feedforward and feedback level. The feedforward level contains motion coordination, force distribution of external forces, creation of internal forces, and an additional loop adding the elastic displacements due to the applied forces to the planned robot positions. The feedback level is organized in the form of an active compliance control law. For adjusting the controller to the, in general, unknown flexible behaviour, which in practice is the main problem of the controller design, a quasi-static model of the system is derived for different contact cases of the object and a procedure is presented, which by use of this model is capable of determining the compliance of the considered system and therefore of adjusting the controller. Experiments with two puma-type robots have been conducted to show the applicability of the self-adjusting control strategy. The task has been to grasp and move an unconstrained object. It is shown, that the system can adjust the control parameters to the unknown system compliance and that the control performance is improved considerably.     

Influence of material handling devices on the physical load during the end assembly of cars

The effect of using a mechanical device on physical load was analysed during the end assembly of cars. Five tasks, further sub-divided into lifting and positioning, were performed by someone experienced in working with and without the mechanical tool. A practical methodology was used: the subjective walk and talk through method, the NIOSH equation (1991), a three-dimensional goniometer (Back Tracker) and surface electromyography (EMG) of the relevant muscle groups. According to the NIOSH equation, 8 out of 10 of the tasks should only be performed by trained workers and preferably with tools. The Back Tracker revealed that the mechanical tools reduced posture angles significantly (p0.05) for installing the windows, but not for left lateroflexion during pre-assembly of windows. It was clear from the EMG analysis that using tools did not always decrease muscular activity significantly. In general, the appropriateness of each tool needs to be evaluated separately taking the subjective criteria into account.

Relevance to industry

In this study, the relevance of using a mechanical device to reduce the physical load during car assembly, is evaluated. As the tools are expensive, it is important to the industry whether they are being used and how efficient they are.     

Foot motions in manual material handling transfer tasks: a taxonomy and data from an automotive assembly plant

Ergonomic job analysis commonly applies static postural and biomechanical analysis tools to particular postures observed during manual material handling (MMH) tasks, usually focusing on the most extreme postures or those involving the highest loads. When these analyses are conducted prospectively using digital human models, accurate prediction of the foot placements is critical to realistic postural analyses. In automotive assembly jobs, workers frequently take several steps between task elements, for example, picking up a part at one location and moving to another location to place it on the vehicle. A detailed understanding of the influence of task type and task sequence on the stepping pattern is necessary to accurately predict the foot placements associated with MMH tasks. The current study examined the patterns of foot motions observed during automotive assembly tasks. Video data for 529 pickup and delivery tasks from 32 automotive assembly jobs were analysed. A minimum of five cycles was analysed for each task. The approach angle, departure angle, hand(s) used, manipulation height and patterns of footsteps were coded from the video. Object mass was identified from the job information sheet provided by the assembly plant. Three independent raters coded each video and demonstrated an intraclass correlation coefficient of 0.54 for identification of the configuration of the lower extremities during terminal stance. Based on an analysis of the distribution of stepping behaviours during object transitions (pickups or deliveries), a transition classification system (TRACS) was developed. TRACS uses a compact notation to quantify the sequence of steps associated with a MMH transition. Five TRACS behaviour groups accounted for over 90% of the transition stepping behaviours observed in the assembly plant. Approximately two-thirds (68.4%) of the object transfers observed were performed with only one foot in contact with the ground during the terminal posture. The results from this paper suggest that a predictive model for choosing a transition stepping behaviour, coupled with a model to scale the selected foot behaviours, is needed to facilitate accurate prospective ergonomic analyses. This study proposes a method for categorising the stepping patterns associated with MMH tasks. The influence of task type and task sequence on the stepping patterns observed during several automotive assembly tasks is discussed. For prospective postural analyses conducted using digital human models, accurate prediction of the foot placements is critical to realistic postural analyses.     

Foot motions in manual material handling transfer tasks: A taxonomy and data from an automotive assembly plant

Ergonomic job analysis commonly applies static postural and biomechanical analysis tools to particular postures observed during manual material handling (MMH) tasks, usually focusing on the most extreme postures or those involving the highest loads. When these analyses are conducted prospectively using digital human models, accurate prediction of the foot placements is critical to realistic postural analyses. In automotive assembly jobs, workers frequently take several steps between task elements, for example, picking up a part at one location and moving to another location to place it on the vehicle. A detailed understanding of the influence of task type and task sequence on the stepping pattern is necessary to accurately predict the foot placements associated with MMH tasks. The current study examined the patterns of foot motions observed during automotive assembly tasks. Video data for 529 pickup and delivery tasks from 32 automotive assembly jobs were analysed. A minimum of five cycles was analysed for each task. The approach angle, departure angle, hand(s) used, manipulation height and patterns of footsteps were coded from the video. Object mass was identified from the job information sheet provided by the assembly plant. Three independent raters coded each video and demonstrated an intraclass correlation coefficient of 0.54 for identification of the configuration of the lower extremities during terminal stance. Based on an analysis of the distribution of stepping behaviours during object transitions (pickups or deliveries), a transition classification system (TRACS) was developed. TRACS uses a compact notation to quantify the sequence of steps associated with a MMH transition. Five TRACS behaviour groups accounted for over 90% of the transition stepping behaviours observed in the assembly plant. Approximately two-thirds (68.4%) of the object transfers observed were performed with only one foot in contact with the ground during the terminal posture. The results from this paper suggest that a predictive model for choosing a transition stepping behaviour, coupled with a model to scale the selected foot behaviours, is needed to facilitate accurate prospective ergonomic analyses. This study proposes a method for categorising the stepping patterns associated with MMH tasks. The influence of task type and task sequence on the stepping patterns observed during several automotive assembly tasks is discussed. For prospective postural analyses conducted using digital human models, accurate prediction of the foot placements is critical to realistic postural analyses.     

融合学习策略与导向果蝇机制的气味源主动定位方法研究

工业生产过程中常发生由有害气体泄漏引起的火灾或爆炸事故,利用载有气体传感器的移动机器人实时监测并搜索定位泄漏气体源是预防重大事故的有效方法,而高效的搜索策略是保证机器人快速准确定位气味源的关键因素.现有的气味源搜索算法存在定位成功率不高和对气味源定位不准的问题,本文提出一种将仿生果蝇算法和学习策略相融合的气味搜索策略.针对传统果蝇算法易陷入饱和收敛的问题,提出一种新的导向果蝇极值更新方式;针对寻优不精的问题,进一步提出一种基于学习策略的导向果蝇气味源搜索算法(OCGFOA).仿真实验结果表明OCGFOA算法完成定位速度更快且离泄漏气味源位置更近,其定位效果更能满足对危险气味源定位的要求;最后,在物理场景下进行气味源主动定位验证实验,证明本文所提算法在实际场景下也具有可行性.     

Error recovery in the assembly of a Self-Organizing Manipulator by using active visual and force sensing

This paper deals with the assembly of aSelf-OrganizingManipulator (SOM) by using the method ofActive Sensing. We set a 6-axis force/torque sensor in the wrist of a manipulator and a CCD camera in the hand of another manipulator. By cooperation of hand and eye, human beings can do a variety of versatile work. The eyes guide the motion of the hand, while the hand moves to make the object easy to see. We try to construct a system working in the same way as a human being. We integrate a vision system, a manipulator, and a force/torque sensor into a hand-eye working system. The scene simplification is based on the controlled motion of camera and manipulator. A method of theAverage Visible Ratio (AVR) is proposed to evaluate the viewpoint of the movable camera. A strategy for planning the assembly is presented. The efficiency of the system is illustrated by experiments.     

QISM：一种基于中间件和服务的无线传感器网络主动QoS体系

提出了一种基于中间件、面向服务的无线传感器网络主动QoS体系QISM,对其设计思想、体系结构、关键模块和工作过程进行了论述.基于应用和网络反馈协商的动态调节机制,基于中间件和服务发布与订阅的体系结构,以及基于Topic和功能域的表达方式,是QISM的重要特点.QISM通过对应用和网络的动态调节,使网络最大限度的支持应用,应用最大程度的适应网络,从而更好地保证了应用的完成,延长了网络生命期.针对典型场景的仿真结果表明,QISM机制具有良好的QoS控制能力和灵活性,支持复杂应用,且同网络结构形式无关.     

基于SVM和RBFN的汽车主动降噪系统传感器故障诊断

汽车主动降噪系统的工作依赖于多个噪声传感器,一旦传感器发生故障,将严重影响降噪效果。为保证汽车主动降噪系统的性能,提出了由支持向量机(SVM)预测模型和径向基神经网络(RBFN)预测模型构成的传感器故障诊断系统,SVM模型判断是否发生传感器故障,RBFN模型则利用各传感器间的信息冗余关系定位故障传感器并对其信号进行重构。仿真结果表明,该诊断系统可有效实现汽车主动降噪系统中的传感器故障诊断及信号重构。与传统的汽车主动降噪系统相比,引入传感器故障诊断系统可保证更稳定的降噪性能。     

Sensor runout compensation in active magnetic bearings via an integral adaptive observer

Sensor runout is one of the main sources of harmonic disturbances in active magnetic bearing systems. This type of the disturbance not only causes harmonic vibrations in the system but also changes the steady-state position of the axis of rotation from the geometric center of the AMB. In this paper, an integral adaptive observer is proposed to identify the dc and harmonic content of the sensor runout and to estimate the states of the system at the same time. The Lyapunov method is used to prove asymptotic stability of the proposed observer. Unlike the proportional observer which amplifies the measurement error, the sensor runout can be completely compensated when the states of the integral adaptive observer are used for feedback stabilization. It is shown that the proposed technique can also attenuate rotor displacements, when both sensor runout and mass unbalance disturbances are applied to the system. Simulation results have been presented for both cases to demonstrate the performance of the integral adaptive observer. Experimental results are also obtained by an AMB test rig, which confirm the effectiveness of the proposed method.     

Sensor-guided micro assembly of active micro systems by using a hot melt based joining technology

This article presents (the most) recent results of the subprojects B4 and B8 of the Collaborative Research Center 516—Design and Manufacturing of Active Micro Systems—which are concerned with the assembly of active micro systems. While subproject B4 investigates sensor guided assembly processes, subproject B8 develops suitable assembly techniques on the basis of non-viscous adhesive systems (hot melts). Process development focuses on the suitability for automation, process times and the applicability of batch processes. The article discusses certain hot melt application techniques that are suitable for batch production, a sensor-guided assembly system as well as different approaches for heat conduction in an automated assembly process for hot melt coated micro components.     

传感器技术的新发展——智能传感器和多功能传感器

智能传感器和多功能传感器是传感技术发展的方向。介绍智能传感器和多功能传感器的概念、功能、结构、特点以及它们的应用和发展趋势。     

基于成本和并行装配的装配序列有向图求解

针对虚拟装配中装配序列规划问题,引入了有向图来描述装配过程中的零件以及零件间的装配约束关系。结合装配成本、并行装配、装配经验优化了装配关系有向图的拓扑排序算法。提出了将装配方向变化次数作为衡量装配成本的一项重要指标。提出了将单次可装配的零件数量作为装配优先方向的参考依据。文章最后给出了装配序列生成的具体算法。