Communication architectures for electrical drives

The paper gives an overview of the communication architectures adopted in the industrial automation for the electrical drives, ensuring a fast data exchange and high performance control. An attempt is made at defining real-time operation for this application field, at reviewing the standardization work done to unify the electrical drive interfaces, and at encompassing the recently accepted solutions, including those based on the industrial Ethernet.     

Experimental Evaluation of an Industrial Application Layer Protocol Over Wireless Systems

Several recent studies have addressed the suitability of current wireless technologies for industrial communications which, frequently, are requested to cope with severe timing constraints. Most of the analysis that have lately appeared in the literature have focused on the performance offered by the lower layers of the communication stack. However, in order to obtain a complete picture, it is important to analyze how this gets coupled with the features of higher layer protocols typically employed by industrial communication applications. In this paper, we investigate the performance obtained by an application layer protocol, derived from those currently employed by wired fieldbuses, running over COTS devices based on two popular wireless communication standards, namely, IEEE 802.15.4 and IEEE 802.11. In particular, we present a mapping of the application service elements onto the services offered by the mentioned wireless systems and discuss some possible design choices. A prototype of the application layer protocol is then implemented for each considered wireless technology and the performance figures evaluated by means of experimental measurements.     

Ethernet-Based Real-Time and Industrial Communications

Despite early attempts to use Ethernet in the industrial context, only recently has it attracted a lot of attention as a support for industrial communication. A number of vendors are offering industrial communication products based on Ethernet and TCP/IP as a means to interconnect field devices to the first level of automation. Others restrict their offer to communication between automation devices such as programmable logic controllers and provide integration means to existing fieldbuses. This paper first details the requirements that an industrial network has to fulfill. It then shows how Ethernet has been enhanced to comply with the real-time requirements in particular in the industrial context. Finally, we show how the requirements that cannot be fulfilled at layer 2 of the OSI model can be addressed in the higher layers adding functionality to existing standard protocols.     

On the use of wireless networks at low level of factory automation systems

Wireless communication systems are rapidly becoming a viable solution for employment at the lowest level of factory automation systems, usually referred to as either "device" or "field" level, where the requested performance may be rather critical in terms of both transmission time and reliability. In this paper, we deal with the use of wireless networks at the device level. Specifically, after an analysis of the communication requirements, we introduce a general profile of a wireless fieldbus. Both the physical and data link layers are taken directly from existing wireless local area networks and wireless personal area networks standards, whereas the application layer is derived from the most popular wired fieldbuses. We discuss implementation issues related to two models of application layer protocols and present performance results obtained through numerical simulations. We also address some important aspects related to data security and power consumption.     

基于多网络的矿井智能化监管系统设计

提出一种矿井智能化监管系统设计方案,该系统包括无线传感器网络（WSN）、工业以太网络、人员定位卡、井下视频手机、监管服务器、监控计算机、数据库、中心交换机、智能化监管信息平台。系统将工业以太网络和无线传感器网络结合,构建井下有线／无线的混合通信系统进行数据传输,井上利用智能化信息监管平台实现与井下作业人员、井上管理人员、井上其他人员的数据通信和资源共享;该系统具有井下人员实时定位、井下与井上实时视频通信、矿井环境监测、智能化信息处理、矿井信息分发、资源调度、异常情况报警等功能,矿井环境监测包括对瓦斯、CO、电化学氧气、硫化氢、风速、矿压、温湿度、矿尘、噪音等环境参数的监测。     

Industrial wireless sensor and actuator networks in industry 4.0: Exploring requirements,protocols, and challenges—A MAC survey

The vision to connect everyday physical objects to the Internet promises to create the Internet of Things (IoT), which is expected to integrate the diverse technologies such as sensors, actuators, radio frequency identification, communication technologies, and Internet protocols. Thus, IoT promises to transfer traditional industry to advance digital industry known as the Industry 4.0. At the core of the Industry 4.0 are the wireless sensor networks (WSNs) and wireless sensor and actuator networks (WSANs) that led to the development of industrial wireless sensor networks (IWSNs) and industrial wireless sensor and actuator networks (IWSANs). These networks play a central role of connecting machines, parts, products, and humans and create a diverse set of new applications to support intelligent and autonomous decision making. The IWSAN is a promising technology for numerous industrial applications because of their several potential benefits such as simple deployment, low cost, less complexity, and mobility support. However, despite such benefits, they impose several unique challenges at different layers of the protocol stack when deploying them for various monitoring and control applications in the Industry 4.0. In this article, we explore IWSAN, its applications, requirements, challenges, and solutions in the context of industrial control applications. Our main focus is on the medium access control (MAC) layer that can be exploited to satisfy such requirements. Our discussion presents extensive background study of the MAC schemes and it reviews the MAC protocols of the existing wireless standards and technologies. A number of application‐specific MAC protocols developed to support industrial applications, which are not part of these standards, are also elaborated. We rationalize to what extent the existing standards and protocols help in solving such requirements as laid down by the Industry 4.0. In the end, we emphasize on existing challenges and present important future directions.     

Cross-Layer Collaborative In-Network Processing in Multihop Wireless Sensor Networks

Emerging wireless sensor network (WSN) applications demand considerable computation capacity for in-network processing. To achieve the required processing capacity, cross-layer collaborative in-network processing among sensors emerges as a promising solution: sensors do not only process information at the application layer, but also synchronize their communication activities to exchange partially processed data for parallel processing. However, scheduling computation and communication events is a challenging problem in WSNs due to limited resource availability and shared communication medium. In this work, an application-independent task mapping and scheduling solution in multihop homogeneous WSNs, multihop task mapping and scheduling (MTMS), is presented that provides real-time guarantees. Using our proposed application model, the multihop channel model, and the communication scheduling algorithm, computation tasks and associated communication events are scheduled simultaneously. The dynamic voltage scaling (DVS) algorithm is presented to further optimize energy consumption. Simulation results show significant performance improvements compared with existing mechanisms in terms of minimizing energy consumption subject to delay constraints     

Delay-sensitive and multimedia communication in cognitive radio sensor networks

Multimedia and delay-sensitive data applications in cognitive radio sensor networks (CRSN) require efficient real-time communication and dynamic spectrum access (DSA) capabilities. This requirement poses emerging problems to be addressed in inherently resource-constrained sensor networks, and needs investigation of CRSN challenges with real-time communication requirements. In this paper, the main design challenges and principles for multimedia and delay-sensitive data transport in CRSN are introduced. The existing transport protocols and algorithms devised for cognitive radio ad hoc networks and wireless sensor networks (WSN) are explored from the perspective of CRSN paradigm. Specifically, the challenges for real-time transport in CRSN are investigated in different spectrum environments of smart grid, e.g., 500 kV substation, main power room and underground network transformer vaults. Open research issues for the realization of energy-efficient and real-time transport in CRSN are also presented. Overall, the performance evaluations provide valuable insights about real-time transport in CRSN and guide design decisions and trade-offs for CRSN applications in smart electric power grid.     

A New Dynamic Energy Efficient Latency Improving Protocol for Wireless Sensor Networks

In delay sensitive applications of wireless sensor network, it is required to monitor the situation continuously with the sensors. The continuous operation and processing delay, may contribute latency in data communication. This results in more energy consumption of the sensor nodes. It is difficult to replace the battery of a sensor node, after the deployment in the network. The efficient energy management and low latency are the important issues in delay sensitive applications as they affect the life of network. There are some limitations in existing routing protocols as they are particularly designed either for energy efficiency or minimum latency. This paper presents the new protocol to overcome some drawbacks of the existing protocols. A concept of distance metric based routing is explored for shortest routing path selection. This helps to reduce the overhead of the network traffic, which results in improvement of energy efficiency and latency. The simulation results are compared with standard ‘AODV’ routing protocol. It is observed that, this ‘Dynamic Energy Efficient and Latency Improving Protocol’ will be very much suitable for wireless sensor networks in industrial control applications.     

基于ZigBee无线传感器网络的工业污水监测系统的设计

针对目前工业污水监测中数据采集难度大、实时性不强等问题,研究并设计了一种基于ZigBee无线传感器网络的污水远程监测系统。系统以ZigBee无线通讯技术为基础,搭建起无线通讯网络,实现了污水数据的自动采集及远距离传输。实验测试表明,系统传输速率快,实时性强,稳定性高,可以有效地对工业污水进行远程监测。     

Wireless medium access control protocols

Technological advances, coupled with the flexibility and mobility of wireless systems, are the driving force behind the Anyone, Anywhere, Anytime paradigm of networking. At the same time, we see a convergence of the telephone, cable and data networks into a unified network that supports multimedia and real-time applications like voice and video in addition to data. Medium access control protocols define rules for orderly access to the shared medium and play a crucial role in the efficient and fair sharing of scarce wireless bandwidth. The nature of the wireless channel brings new issues like location-dependent carrier sensing, time varying channel and burst errors. Low power requirements and half duplex operation of the wireless systems add to the challenge. Wireless MAC protocols have been heavily researched and a plethora of protocols have been proposed. Protocols have been devised for different types of architectures, different applications and different media. This survey discusses the challenges in the design of wireless MAC protocols, classifies them based on architecture and mode of operation, and describes their relative performance and application domains in which they are best deployed.     

Wireless Aspects of Telehealth

Telehealth is the use of electronic information and communication technology to deliver health and medical information and services over large and small distances. Broadband wireless services available today, along with more powerful and convenient handheld devices, will enable a transformational change in health management and healthcare with the introduction of real-time monitoring and timely responses to a wide array of patient needs. Further, a network of low-cost sensors and wireless systems help in creating constantly vigilant and pervasive monitoring capability at home and at work. This paper addresses recent efforts in this growing field, including standards, system architectures, propagation models, and lower layer protocols for body area networks. The paper also suggests the use of cooperative transmission-based strategies for such wireless topologies.     

基于以太网模块IP传感器的研究

对于工业现场设备的监测控制,人们不再满足于集散控制系统和现场总线控制系统,为此,结合传感技术和Internet技术,将传感器制成网络产品,并实现网络通信TCP/IP协议。该文系统地介绍了IP传感器、TCP/IP协议及其实现原理,阐述了以太网通信模块的实现方案、软件设计,给出了网卡的复位及初始化事例。所研制的IP传感器具有远程数据访问、信息实时发布与共享以及在线编程等功能,为构建具有更高性能价格比的测控自动化系统成为可能,该模块在远程自动化领域具有广阔的应用前景。     

Multifunctional and Wearable Patches Based on Flexible Piezoelectric Acoustics for Integrated Sensing,Localization, and Underwater Communication

Flexible and wearable sensors are highly desired for health monitoring, agriculture, sport, and indoor positioning systems applications. However, the currently developed wireless wearable sensors, which are communicated through radio signals, can only provide limited positioning accuracy and are often ineffective in underwater conditions. In this paper, a wireless platform based on flexible piezoelectric acoustics is developed with multiple functions of sensing, communication, and positioning. Under a high frequency (≈13 MHz) stimulation, Lamb waves are generated for respiratory monitoring. Whereas under low-frequency stimulation (≈20 kHz), this device is agitated as a vibrating membrane, which can be implemented for communication and positioning applications. Indoor communication is demonstrated within 2.8 m at 200 bps or 4.2 m at 25 bps. In combination with the sensing function, real-time respiratory monitoring and wireless communication are achieved simultaneously. The distance measurement is achieved based on the phase differences of transmitted and received acoustic signals within a range of 100 cm, with a maximum error of 3 cm. This study offers new insights into the communication and positioning applications using flexible acoustic wave devices, which are promising for wireless and wearable sensor networks.     

Energy-Aware Optimization Model in Chain-Based Routing

Sensor networks are deployed in numerous military and civil applications, such as remote target detection, weather monitoring, weather forecast, natural resource exploration and disaster management. Despite having many potential applications, wireless sensor networks still face a number of challenges due to their particular characteristics that other wireless networks, like cellular networks or mobile ad hoc networks do not have. The most difficult challenge of the design of wireless sensor networks is the limited energy resource of the battery of the sensors. This limited resource restricts the operational time that wireless sensor networks can function in their applications. Routing protocols play a major part in the energy efficiency of wireless sensor networks because data communication dissipates most of the energy resource of the networks. The above discussions imply a new family of protocols called chain-based protocols. In the protocols, all sensor nodes sense and gather data in an energy efficient manner by cooperating with their closest neighbors. The gathering process can be done until an elected node calculates the final data and sends the data to the base station. In our works, we have proposed two methods to optimize the lifetime of chain-based protocols using Integer Linear Programming (ILP) formulations. Also, a method to determine the bounds of the lifetime for any energy-efficient routing protocol is presented. Finally, simulation results verify the work in this chapter. Furthermore, previous researches assume that the base station position is randomly placed without optimization. In our works, a non convex optimization model has been developed for solving the base station location optimization problem.     

IDRA: A flexible system architecture for next generation wireless sensor networks

Wireless sensor networks consist of embedded devices (sensor nodes), equipped with a low-power radio. They are used for many applications: from wireless building automation to e-health applications. However, due to the limited capabilities of sensor nodes, designing network protocols for these constrained devices is currently very challenging. Therefore, this paper presents the IDRA platform: an information driven architecture designed to support next-generation applications on resource constrained networked objects. IDRA supports simple but useful optimizations at an architectural level. These include support for cross-protocol interactions, energy efficiency optimizations, QoS optimizations (packet priorities, dynamic protocol selection), mobility support and heterogeneous network support. The paper shows how the development of protocols is improved by using an architecture which delegates specific tasks to a central system, decreasing the memory requirements of associated network protocols. A thorough experimental performance analysis demonstrates that IDRA is much more scalable in terms of memory requirements, energy requirements and processing overhead than traditional system architectures. Finally, the paper discusses how the optimizations presented in this paper can be used for the clean-slate design of architectures for other wireless or wired network types.     

Self-reconfiguration of real-time communication in cyber-physical systems

Today, in domains like automation and robotics systems consist of various sensors and computation nodes. Due to the temporal dependency in quality of measured data, such Cyber-Physical Systems (CPS) commonly have real-time requirements on communication. In addition, these systems shall become more flexible and scalable, e.g., by adding new components to the CPS. This would be most suitable if a CPS could react to the presence of a new component and reconfigure itself to run afterward with the new component integrated to the CPS. This capability is covered by the term Plug-and-Produce. In this paper, we propose a concept to enable Plug-and-Produce within a CPS whose network uses different communication media, e.g., Ethernet and CAN. To enable real-time communication provided by different communication protocols, their different synchronization mechanisms have to be combined to get a common time base within the entire system. For this purpose, we consider Ethernet as well as CAN-based real-time communication protocols and their synchronization mechanisms. The proposed concept for self-reconfiguration aims to be integrated into our three layered software architecture that is presented as well.     

Cluster based wireless sensor network routing using artificial bee colony algorithm

Due to recent advances in wireless communication technologies, there has been a rapid growth in wireless sensor networks research during the past few decades. Many novel architectures, protocols, algorithms, and applications have been proposed and implemented. The efficiency of these networks is highly dependent on routing protocols directly affecting the network life-time. Clustering is one of the most popular techniques preferred in routing operations. In this paper, a novel energy efficient clustering mechanism, based on artificial bee colony algorithm, is presented to prolong the network life-time. Artificial bee colony algorithm, simulating the intelligent foraging behavior of honey bee swarms, has been successfully used in clustering techniques. The performance of the proposed approach is compared with protocols based on LEACH and particle swarm optimization, which are studied in several routing applications. The results of the experiments show that the artificial bee colony algorithm based clustering can successfully be applied to WSN routing protocols.     

Timeliness of real-time IP communication in switched industrial Ethernet networks

Through several giant evolutionary steps, Ethernet has become an almost ubiquitous technology for communication. Being versatile enough to be employed in new and various fields of application, it is now making inroads in factories. However, automated systems are different from many other applications of Ethernet,first and foremost because they require the network technology to deliver real-time performance. In the present study, a number of critical aspects of Ethernet, usually referred to as an Industrial Ethernet, are examined. More specifically, there is a focus on the application-to-application delay and jitter characteristics of such networks, when using Internet protocols such as UDP and TCP. It is demonstrated how important it is to take control of the latency in the station nodes, since the main communication delays occur inside the nodes, and different solutions are presented for controlling these delays. In particular, a priority-based protocol stack is assessed. The results show that real-time, Ethernet-based IP communication is now adequate even for demanding automated applications. In this paper, substation automation (power distribution) is used as an example of a demanding automation system.     

无线传感器网络的新进展与应用

为完成实时监测、感知和采集各种监测环境或对象的信息,将智能传感器组成分布式信息测控网络。无线传感器网络是传感器智能化发展的趋势。它是以数据获取与数据管理为核心的全新网络,综合了传感器技术、嵌入式计算技术、分布式信息处理技术和无线通信技术。介绍了无线传感器网络节点、无线传感器网络、无线传感器网络的最新进展,并给出了无线传感器网络的应用。