Intelligent Assist Systems for Flexible Assembly

The growing number of product variants, smaller lot sizes, reduced time to market and shorter lifecycles of products have lead to increasing demands on automation equipment and concepts. As a solution, hybrid human integrated approaches are proposed. The idea is to combine human flexibility, intelligence and skills with the advantages of sophisticated technical systems. Intelligent assist systems (IAS) represent a novel class of assembly systems capable of working with human operators in two modes: workplace sharing and time sharing. This paper presents a novel collaborative robot system (“Cobot”) capable of sharing the workspace with the human co-worker and collaborating with him through direct physical contact.     

改进的机器人视觉与传送带综合标定方法

传统六自由度机器人视觉与传送带的标定方法一般忽略了相机畸变的像素偏差和设备安装过程中的角度偏差,使得传送带上的目标难以精确定位。针对传统标定方法的局限性,提出一种高精度机器人传送带与视觉的综合标定方法。在校正相机径向与切向畸变以及安装角度的基础上,构建机器人坐标系中物体的位移及其在图像坐标系下位移的比例关系,在传送带标定过程中,应用此比例关系,通过设置像素坐标误差阈值的方法校正机器人坐标与传送带坐标系的关系。改进后的标定方法灵活性强,实验结果表明:该方法定位精度有较大的提高。     

Singularity Prediction for Parallel Robots for Improvement of Sensor-Integrated Assembly

The frequent occurrences of singularities inside a parallel robot's workspace and in certain cases of sensor integration non-deterministic end-effector trajectories demand a powerful online singularity prediction and a control design that is capable of displacing motion algorithms. The theory of a power-inspired index of closeness to a singularity pose for parallel kinematic manipulators is illumined and presented in this paper, supported by comparison to Grassmann geometry and experimental results achieved on a HEXA robot. An experimentally validated strategy for jerk bounded braking the end-effector while approaching a singularity and an algorithm for departing it again are presented as well.     

Robot based system for the automation of flow assembly lines

In this paper a promising approach to the automation of flow assembly lines is presented. The developed system uses a standard industrial robot and synchronizes it to the product in all degrees of freedom. The synchronization is enabled by dividing the assembly process in different phases and controlling the robot in each phase with an adequate sensor system. Besides that a compliance is integrated into the gripper system in order to reduce high contact forces and tolerate high frequent pose deviations. Main advantages of the synchronized assembly are the avoidance of buffers and the reduction of the throughput time.     

Development of Hybrid Assembly Workplaces

In times of shortened innovation cycles, increasing product variation and demands for faster delivery, the flexibility of production systems is crucial for success. Hybrid workplaces, dynamically configurable for both human workers and robots, help to increase the flexibility. The robot kinematics employed, the available sensors, and the grasping conditions involved in the assembly process mainly determine the changeover effort of a workplace. In this paper, different concepts for hybrid workplaces are introduced and compared with respect to investment costs and configuration effort. Concept application and evaluation are illustrated by final assembly of flat screen monitors.     

Automated Assembly of Mechatronic Products

The synergetic combination of mechanical engineering, electrical engineering, electronics and information technology enables mechatronic products to offer high levels of flexibility and performance. This interdisciplinary interaction requires changes in product structure and accordingly adapted in production strategies. The approach outlined in this article shows the specific use of the product structure with a view to increasing assembly efficiency. The product is actively integrated in the assembly process by setting up an IT link and making use of its sensor/actuator equipment and software, thus providing support for the production system. This makes it possible to increase the efficiency of automation while at the same time reducing assembly costs.     

振动控制并联机器人的标定综述

在分析和总结现有并联机器人运动学标定方面资料的基础上,简述了影响并联机器人运动精度的误差来源和标定准则,详细介绍了不同运动学参数标定法的特点,并提出了当前用于振动抑制的并联机器人运动学标定的难点。     

A Kinematic Calibration Method for Industrial Robots Using Autonomous Visual Measurement

Several new methods have been developed to achieve practical accuracy for offline programming of robots and its applicability to the real world. In this paper, a new kinematic calibration method is proposed to automatically improve absolute positioning accuracy of robots. Key points of the method include autonomous measurement and the automatic generation of measuring poses. A new visual feedback motion control method of the robot is proposed to achieve accurate measurement. An algorithm is also proposed to improve the condition of measuring poses automatically. The effectiveness of the proposed methods and algorithm was investigated through experiments with actual robots.     

基于特征值坐标的机器人局部抛磨定位方法

提出一种复杂曲面机器人局部抛磨定位方法。在测量点集中选取种子点,利用多元统计学中的协方差矩阵,建立各点相对于旋转和平移坐标变换不变的特征值坐标,以此直接搜索抛磨零件的设计曲面,生成对应点对;进而将各点主轴取向归一化,给出一种计算测量数据和模型曲面间坐标变换的方法;在此基础之上,求解变换矩阵并通过最小距离目标函数选取正确的局部定位坐标变换,实现机器人到复杂曲面指定抛磨区域的准确定位。实验结果显示:该方法简捷、可靠且容易实现,特别适用于复杂曲面零件的局部抛磨加工定位。     

Methodological Approach and Reconfiguration Tool for Assembly Systems

Assembly lines design is intended to solve many problems related to assembly operations. The introduction of a new product should often entail the salvage of existing assembly lines. This work proposes a methodology for assembly line reconfiguration, to rationalize and support the redesign process of assembly systems. This research formalizes a representation model and a method for assembly line reconfiguration. The model describes the main characteristics and significant features of the assembly process. The study is concerned with three fundamental models, the first describes assembly line structures. The second illustrates component assembly features and the third produces all the assembly sequences. The assembly line reconfiguration method provides an analysis and estimation tool on the reconfiguration process complexity. The method proposed is also meant to be a tool to identify the operational flexibility limit. The method results point out the way to implement assembly system reconfiguration and gives detailed information about the assembly line. Each assembly line, facing a new product to be assembled, is processed with the reconfiguration method and receives operative results for reconfiguration process and quality indicators.     

关于工业机器人标定方法的研究

机器人标定是国内外研究的热点,已成为机器人生产及使用过程中的重要工作之一。围绕机器人连杆参数标定、工具坐标系标定、机器人与其他设备之间的标定这3个方面进行了研究,从标定原理到具体方法应用,不同的标定对象标定方法不相同。提出了现有标定技术的不足和标定技术的发展趋势,为后续机器人标定技术的发展奠定了一定的基础。     

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.     

Modeling and Control of Compliant Assembly Systems

The assembly of compliant, non-rigid parts is widely used in automotive, aerospace, electronics, and appliance manufacturing. Dimensional variation is one important measure of quality in such assembly. This paper presents models for analyzing the propagation of dimensional variation in multi-stage compliant assembly systems and the use of such models for robust design and adaptive control of assembly quality. The models combine engineering structure analysis with advanced statistical methods in considering the effect part variation, tooling variation, as well as part deformation due to clamping, joining and springback. The new adaptive control algorithm makes use of the fine adjustment capabilities in new programmable tooling in achieving reduction of assembly variation.     

机器人抓取的三维手眼标定方法研究

在视觉感知识别目标位姿后,机器人正确移动到指定位姿需进行手眼标定。若机器人进行三维空间操作,需进行三维手眼标定。针对空间物体抓取提出方法：通过设定机器人在x、y、z三个方向上的限位,根据工作需要为机器人定义一个工作区域,机器人以定步长定轨迹路线在区域内移动,使用迭代最近点算法求解手眼标定转换矩阵,采用下山单纯形法对转换矩阵进行优化,减小标定误差。实验结果表明：平均标定误差比传统基准法减小了18.90%,所需时间减少了49.12%。     

Continuous Failure Diagnosis for Assembly Systems using Rough Set Approach

Increasingly, companies require faster ramp-up in order to cope with shorter production cycles and greater demand for product variety. Since quality and dimensional problems are one of the major reasons for delay during ramp-up, rapid diagnosis of dimensional failures is of critical concern. Given the lack of historical data and incomplete process knowledge in ramp-up, a Rough Set based diagnosis methodology is proposed which focuses on developing: (1) Self-learning ability to detect new faults as a system undergoes adjustments; and (2) A continuous diagnostic for faults rather than a crisp definition of faults. A case study illustrates the proposed approach.     

手机键盘柔性装配机器人的研制

本文介绍了一种用于手机键盘柔性装配的机器人,由键盘产品设计图可以自动地生成机器人装配动作序列,特殊设计的末端执行器极大地提高了装配精度和效率。应用结果证明了机器人的令人满意的工作能力。     

机器人动力学标定综述

动力学标定在机器人控制中起着非常重要的作用。本文从一般动力学标定和基于神经网络的动力学标定两方面对现有机器人动力学标定方法和研究现状进行了分析和总结。并详细介绍了每种标定方法的特点、存在的问题以及研究现状。最后对机器人动力学标定的发展方向进行了简要论述。     

机器人轴孔装配控制策略的分析与设计

为了保证机器人在任意的抓取位姿皆能够完成3种形状轴孔零件的装配任务,提出了一种利用力传感器实现主从双臂协调运动的轴孔装配策略。详细描述了该策略在3个不同阶段的控制方法,在理论上保证了该策略的可行性。搭建了实验平台,针对3种不同形状的零件,分别采用4组不同的抓取位姿进行了实验。实验结果表明:由于零件形状的不同使得双臂在Z轴方向的调整角度不同,导致了装配任务耗时的差异性;对任意形状的零件以任意的位姿抓取,系统均能够在最短的时间内搜索出准确的装配位姿,以完成各种复杂形状轴孔零件的装配任务,验证了所提出的主从双臂协调下的轴孔装配策略的可行性和有效性。     

Co-Evolution of Product Families and Assembly Systems

To cope with the intense global competition that is characterized by high product variety and short life cycles, manufacturers need to share manufacturing systems across products and product generations. Co-evolution of product families and assembly systems is proposed as a novel methodology for the joint design and reconfiguration of product families and assembly systems over several product generations. The co-evolution methodology capitalizes on the opportunities for design and assembly system reuse that are offered by modular product architectures and reconfigurable assembly systems. As a result, co-evolution can lead to reduced product development costs and increased responsiveness to market changes.     

基于激光跟踪仪的机器人参数标定方法

利用激光跟踪仪高精度测量的特性,通过变换机器人不同的位姿从而实现对机器人各杆长的直接精确测量,其标定结果与使用RoboDyn软件标定的结果进行比对,两种方法都能明显提升机器人位置准确度,但后者提升得更加显著.同时也分析了基于激光跟踪仪直接测量机器人杆长参数过程中的误差来源.试验结果证明,基于激光跟踪仪对机器人杆长参数进...