试论工业以太网实时通信技术

工业以太网进入工业控制领域是工业自动化的发展趋势，其中主要障碍是以太网的非实时通信。简要介绍了几种工业以太网的实时通信技术。侧重介绍分散自动化接口解决工业以太网通信实时性的方法——RITS协议。讨论了RTIS协议实现实时通信的性能。     

智能化在线实时八通道流量测量相关仪

0引言相关技术在工业、通讯及科学研究中具有广泛的应用价值。相关流量测量更是解决如两相流等困难流量测量的有利手段。由于以往成本低的软件式相关仪实时性差,而实时性强的硬件式相关仪成本高。因此,限制了相关技术的广泛应用。本文在分析与总结了国内外流量测量用相?..     

十一种工业实时以太网系统结构概论

本文较全面论述了现场总线与工业实时以太网国际标准的最新进展,阐述了工业实时以太网技术现状,较深入分析了十一种工业实时以太网的系统结构,为工程技术人员应用选型提供参考,同时论述了实时以太网技术今后的发展趋势。     

一种简单有效的实时以太网研发

近年来实时以太网技术快速发展;文章分析和借鉴了当前国际上有多种实时以太网协议如SERCOS III、EtherCAT、PROFI-NET-IRT等,并提出了一种简单却不失高效的新型实时以太网协议,进而完成了协议主站与从站的设计制作;最后搭建实时以太网原型验证平台进行评测。     

实时以太网与边缘智能融合控制器设计

为了减少数据通信链路并提高预警事件数据上报的实时性和事件侦测的及时性,将视频事件检测识别与实时以太网通信在边缘控制端直接联系并融合。设计的从站控制器将识别的数据、相似度分数与实时采集的数字量、模拟量数据组包发送给监控主站,主站通过预设控制逻辑与从站控制器进行数据互通,与逻辑联动实现对象的远程控制和管理。此外,通过光模块通信方式级联组网实现超远距离通信,降低了现场布线复杂度与布线成本。     

升级到工业以太网:PROFINET

在最近一期的《工业以太网》中,我们通过考虑Modbus TCP——一种到基本串行现场总线的简单网络扩展,开始从事关于工业网络协议的介绍性丛书。在这个版本中,我们考查了Profinet,或许从理论上是完整的符合工业网络应用。Profinet也起源于现场总线,其设计来自于将企业资源管理引入工厂每个领域的目标。在构建一个已安装的基于多样化Profibus现场总线类型中,Profinet也以一种类似但有较大差异的方式,连接在工厂自动化数据网络中。     

十一种工业实时以太网系统结构概论

本文较全面论述了现场总线与工业实时以太网国际标准的最新进展,阐述了工业实时以太网技术现状,较深入分析了十一种工业实时以太网的系统结构,为工程技术人员应用选型提供参考,同时论述了实时以太网技术今后的发展趋势。     

基于透视投影的激光跟踪测量系统可视性分析

针对现有激光跟踪测量系统可视性分析方法在计算效率方面的不足,提出一种基于透视投影的激光跟踪测量系统可视性分析方法。给出了激光跟踪仪可视性分析的数学定义,利用测点与站位点之间的关系对可视性分析进行描述;利用包络盒对障碍物进行简化,同时根据障碍物、测点、站位点之间的关系,剔除了不参与可视性分析运算的障碍物;在此基础上,利用透视投影的原理,对障碍物在跟踪仪可布置平面上的投影进行了求解,并利用该投影与站位点之间是否包含的关系,得到了测点与站位点之间的可视性矩阵,结合提出的可视性势能的概念,对跟踪仪满足可视性的区域进行了求解。最后,以某飞机舱门检验工装的测量为例,验证了该方法和模型的正确性和有效性。     

一种激光跟踪仪误差标定装置

激光跟踪仪作为一种精密测量仪器近年来已得到广泛运用,因其精度受环境、仪器自身及操作等因素影响,其测量精度一直难以提升。针对这一问题,本文以激光跟踪仪系统的误差模型为基础,设计了一款激光跟踪仪的误差标定装置,提出基于标准距离的位姿测量误差标定方法,对位姿测量系统误差进行补偿,从而提升激光跟踪仪的测量精度。     

众所瞩目的十四种工业以太网解决方案

工业自动化依靠工业通讯，在过去的15年里，这主要通过现场总线来完成。他们从上世纪80年代末首要任务是把现场总线作为电缆替代品，已经发展到自动化系统，其功能和应用远远超过那些创造者们最初的构想。洞察工厂自动化、过程自动化以及楼宇技术的所有分支，市场逐渐被所有基于以太网的新的通讯解决方案所覆盖。这就需要通过着手于相关的学术研究，从而弄清其贡献所在。     

Development and integration of a concurrently executing interactive user interface for the I-STAT protable clinical analyzer: A case study in real-time systems integration

A novel real-time scheduler was developed to implement an interactive user interface for an existing state-of-the-art, hand-held blood analyzer. A software-timer-based scheduler was designed and implemented and guaranteed schedulability analysis performed to ensure that all hard execution deadlines could be met at run time. An execution bandwidth preservation mechanism that increases the robustness and predictability of the scheduler is presented. The paper is a case study that describes the design and development process from a point of view that emphasizes the importance of the systems integration issues that were encountered.     

基于反馈控制的嵌入式实时系统调度算法设计

针对嵌入式实时系统在系统负载模型不确定的情况下系统的实时任务错过率过高以及调度稳定性差的问题,提出了一个基于反馈控制的调度模型.该模型主要由改进的多级队列调度器和3个控制器(准入控制器、执行等级控制器、比例积分微分(PID)控制器)组成.任务的错过率偏差反馈到PID控制器,产生相应的调整量并作用于其他两个控制器,对实时任务的执行等级进行调整, 经过调整的任务被调度器调度执行.在对模型中每个部件进行了一些结构调整和改进设计之后,将该调度模型应用于嵌入式可配置操作系统(eCos)中.实验结果表明,该模型降低了任务的时限错过率,同时解决了系统频频超载的问题.     

A concept of dynamically reconfigurable real-time vision system for autonomous mobile robotics

This paper describes specific constraints of vision systems that are dedicated to be embedded in mobile robots. If PC-based hardware architecture is convenient in this field because of its versatility, flexibility, performance, and cost, current real-time operating systems are not completely adapted to long processing with varying duration, and it is often necessary to oversize the system to guarantee fail-safe functioning. Also, interactions with other robotic tasks having more priority are difficult to handle. To answer this problem, we have developed a dynamically reconfigurable vision processing system, based on the innovative features of Cleopatre real-time applicative layer concerning scheduling and fault tolerance. This framework allows to define emergency and optional tasks to ensure a minimal quality of service for the other subsystems of the robot, while allowing to adapt dynamically vision processing chain to an exceptional overlasting vision process or processor overload. Thus, it allows a better cohabitation of several subsystems in a single hardware, and to develop less expensive but safe systems, as they will be designed for the regular case and not rare exceptional ones. Finally, it brings a new way to think and develop vision systems, with pairs of complementary operators.     

大功率脉冲激光光斑面积的实时控制系统

讨论了大功率脉冲激光光斑面积的实时检测与控制方法,研制了采用波长532 nm的连续激光器和CCD—FPGA技术来脉冲激光光斑面积实时控制系统。实验分析了本系统的技术特性:激光光斑、CCD视频信号以及二值化信号;CCD视频信号二值化阈值为405 mV,而FPGA的控制误差范围为十进制数24;计算及标定激光光斑面积,光斑面积测量的相对误差最大为0.5%,而绝对误差在8μm2范围内。本系统可以直接应用于激光微抛光的能量密度实时控制。     

基于MCF52233的通用远程测控系统平台的研究

分析研究了远程测控系统的共性,建立了测控系统的一般模型,利用Freescale公司的32位ColdFire系列微控制器MCF52233,提出了基于嵌入式以太网的单芯片远程测控系统通用平台的设计方案。给出了利用该平台对实际项目进行二次开发的应用方法与实现细节。实践结果表明,这种平台化的开发方法可以有效地提高软硬件的可重用性、避免重复劳动、缩短开发周期。     

Accuracy improvement of a 3D passive laser tracker for the calibration of industrial robots

The laser tracker has been used as the mainstream instrument for the position accuracy calibration of industrial robots for quite a long time. However, due to the complexity of the built-in dual-axis active servo tracking system, its cost is high and the target reflector has to adjust its pose frequently, so it cannot be popularized in the production and application sites of industrial robots. Based on this drawback, a 3D passive laser tracker (3DPLT) with high precision, simple structure, easy operation and low cost is proposed in this paper. Firstly, the overall structure of the system is designed, and its position error model based on the principle of spherical coordinate measurement and vector transfer method is established. Then, the error parameters are identified by experiments to formulate the error compensation model. Finally, the multi-pose and large-range spatial error compensation verification experiments of the system are carried out on a commercial coordinate measuring machine. The results show that the spatial volumetric errors of the 3DPLT can achieve within 40 μm after compensation with a good repeatability of ±4 μm. A comparison contouring test with a commercial ballbar is also carried out to validate its applicability of robot calibration.