Wireless Industrial Monitoring and Control Using a Smart Sensor Platform

A wireless smart sensor platform (based on patent pending technologies, Ramamurthy ) targeted for instrumentation and predictive maintenance systems is presented. The generic smart sensor platform with "plug-and-play" capability supports hardware interface, payload and communications needs of multiple inertial and position sensors, and actuators, using a RF link (Wi-Fi, Bluetooth, or RFID) for communications, in a point-to-point topology. The design also provides means to update operating and monitoring parameters as well as sensor/RF link specific firmware modules "over-the-air." Sample implementations for industrial applications and system performance are discussed     

Photovoltaics in the assessment of wireless sensor network reliability with changing environmental conditions

This paper presents a reliability assessment of a wireless sensor network (WSN) equipped with mini photovoltaic cells (PV‐WSN) under natural environmental conditions while accounting for different types of system failures. In particular, our assessment considers the hardware specifications of the sensors, photovoltaic (PV) specifications, the use of rechargeable batteries, communication protocols, and various elements required for efficient detection of environmental conditions. We accomplished this by developing a simulator that generated data for 2 broad WSN conditions: (1) WSN without PV and (2) WSN with PV. The dynamic source routing protocol was employed for these simulations, and the following variables were assessed for both conditions: WSN reliability, the impact of energy consumption on the network, and the types of failures that lead to sensor unavailability. The following assumptions were made to run the simulation: the distribution of WSN nodes is random, with 1 sink node per rectangular cluster, the sensor nodes are structurally and functionally identical, environmental interference and suboptimal orientation impair PV cell recharge capacity randomly, and no communication loss occurs. Our reliability assessment assumed extreme environmental conditions and further made assessments of component reliability that included the following parameters: sensor and PV cell hardware specifications, the rechargeable nature of PV cell batteries for different sensor activity states, the availability of sunlight for powering PV cells, and the energy efficiency of PV cells. We found that network lifetime was prolonged for the PV‐WSN condition over the WSN without PV condition, introducing a role for PV cells as potential energy sources for WSNs.     

Advances in the development of built-in diagnostic system for filament wound composite structures

Monitoring the structural integrity of filament wound composite structures such as solid rocket motor cases and liquid fuel bottles can help prevent catastrophic failures and prolong their service life. An integrated structural health monitoring system has been developed by Acellent as a non-destructive evaluation tool for detecting hidden damage in filament wound composite structures. The system includes a built-in sensor network, supporting diagnostic hardware and data processing/analysis software. A prototype of a filament wound composite bottle with embedded SMART Layers has been fabricated successfully at NASA Marshall Space and Flight Center. This demonstrated the compatibility of the SMART Layer to filament winding process. Impact tests were performed on the prototype bottle to generate damage. A scan of the entire bottle by the distributed network of sensors using Acellent’s diagnostic system was able to locate the damage. The built-in signal processing and imaging techniques employed by the software demonstrated the ability of the software to display the impact damage with relative ease in the face of temperature change.     

Comment: Toward the practical use of expert system technique for process disturbance management

A methodology is proposed which can be used to design real-time expert systems for on-line process disturbance management. This methodology encompasses diverse functional aspects that are required for an effective process disturbance management: (1) intelligent process monitoring and alarming, (2) on-line sensor data validation and sensor failure diagnosis, (3) on-line hardware (besides sensors) failure diagnosis, and (4) real-time corrective measure synthesis. Accomplishment of these functions is made possible through the integrated application of the various models: goal-tree success-tree, process monitor tree, sensor failure diagnosis, and hardware failure diagnosis models. This paper presents and discusses the various models along with the overall algorithm of the methodology. The application of the methodology to a target process, a typical main feedwater system of a nuclear power plant which employs a complex control mechanism, will be presented in a companion paper.     

基于ARM的包装袋成型机嵌入式控制系统设计

目的为提高包装袋成型机的控制精度、实时性、系统集成度,基于ARM微控制器设计一种嵌入式控制系统。方法详细论述包装袋成型机的工作原理,通过送料、牵引、热封、分切等工序,将包装薄膜制成包装袋。给出硬件设计方法,包括控制器、传感器模块、电动执行模块等。同时讨论伺服电机升降速控制算法和张力浮动辊控制算法,基于u C/OS-II给出软件设计方法。结果该控制系统具有集成度高、实时性好、开发成本不高等优点。结论该控制系统能够满足包装袋成型机的工艺要求和控制需求。     

基于ARM-WINCE的音视频监控系统设计

监控系统在工业生产和日常生活中有着广泛的应用,设计了一种采用嵌入式处理器与嵌入式操作系统相结合的音视频监控系统。系统硬件平台由CCD图像传感器、GO7007SB视频编码器、S3C2410嵌入式处理器组成,负责视频数据的采集和MPEG-4压缩编码;软件平台采用Windows CE 5.0作为操作系统,软件实现了数据流的RTP封装和发送。详细论述了系统设计、硬件设计和软件设计,实际运行效果表明该系统稳定可靠,能较好地满足监控要求。此设计架构可大大降低开发难度,缩短开发周期,具有很好的可维护性和性价比。     

Highway Bridge Assessment Using an Adaptive Real-Time Wireless Sensor Network

A real-time wireless sensor network platform capable of maintaining lossless data transmission over several minutes of continuous, high-rate sampling is presented in this paper. The platform was designed specifically to provide the capability to enable expeditious system identification, as well as load rating of highway bridges without compromising the typical data acquisition parameters employed in comparable cable-based tests. Consequently, the hardware signal conditioning interface permits data collection from a variety of sensors typical to structural health monitoring, including accelerometers, strain transducers, and temperature sensors. The embedded software features a proprietary network transmission protocol capable of lossless, real-time delivery of up to 40 measurement channels at an effective sampling rate of 128 samples per second per channel. Documented in this paper is a field study on an end-of-service highway bridge in which ambient vibration monitoring was performed using 60 accelerometers interfaced with 30 wireless sensor nodes operating within one of two simultaneously operating star topology networks. In addition, an experimental load rating of the entire structure was performed through large-scale strain measurement facilitated by the same wireless sensor network platform.     

System Performance of Wireless Sensor Network Using LoRa–Zigbee Hybrid Communication

Wireless sensor network (WSN) is considered as the fastest growing technology pattern in recent years because of its applicability in varied domains. Many sensor nodes with different sensing functionalities are deployed in the monitoring area to collect suitable data and transmit it to the gateway. Ensuring communications in heterogeneous WSNs, is a critical issue that needs to be studied. In this research paper, we study the system performance of a heterogeneous WSN using LoRa–Zigbee hybrid communication. Specifically, two Zigbee sensor clusters and two LoRa sensor clusters are used and combined with two Zigbee-to-LoRa converters to communicate in a network managed by a LoRa gateway. The overall system integrates many different sensors in terms of types, communication protocols, and accuracy, which can be used in many applications in realistic environments such as on land, under water, or in the air. In addition to this, a synchronous management software on ThingSpeak Web server and Blynk app is designed. In the proposed system, the token ring protocol in Zigbee network and polling mechanism in LoRa network is used. The system can operate with a packet loss rate of less than 0.5% when the communication range of the Zigbee network is 630 m, and the communication range of the LoRa network is 3.7 km. On the basis of the digital results collected on the management software, this study proves tremendous improvements in the system performance.     

A grid of dielectric sensors to monitor mold filling and resin cure in resin transfer molding

A grid of 50 dielectric sensors has been embedded in the walls of a mold to monitor resin transfer molding (RTM). The capacitance of each sensor increased as resin occupied the space between sensor plates, and it decreased with curing. Monitoring data can be used for process control to prevent dry spots and to determine when to de-mold the part. In previous studies, Skordos et al. [Skordos AA, Karkanas PI, Partridge IK. A dielectric sensor for measuring flow in resin transfer molding. Meas Sci Technol 2000;11:25–31] used a lineal sensor, Hegg et al. [Hegg MC, Ogale A, Mescher A, Mamishev AV, Minaie B. Remote monitoring of resin transfer molding processes by distributed dielectric sensors. J Compos Mater 2005;39(17)] used three large sensors. As experimentally shown in this study, these lineal or large-plate dielectric sensors may mislead since a sensor measures total fraction of the sensor’s plate area occupied by resin but not the resin’s whereabouts. To avoid ambiguity and yet maintain detailed monitoring, a sensor grid was made at the projections of embedded orthogonal electrodes. The developed sensor operation system eliminated tedious and costly manufacturing of conventionally shielded separate sensors. The success of the developed sensor system was demonstrated in RTM experiments.     

面向机械振动信号采集的无线传感器网络节点设计

针对现有无线传感器网络节点的不足和机械振动信号采集的需求,设计了一种可实现机械振动信号采集和片上处理的无线传感器网络节点。该节点采用MEMS加速度传感器拾取振动信号,以低功耗FPGA芯片为控制核心,采用了可编程片上系统技术,将数据采集、存储、处理和传输等控制功能模块集成到单个FPGA芯片中。本文着重介绍了节点数据采集、存储和传输部分的硬件电路和控制逻辑设计,对比实验表明该节点能有效采集和监测机械振动信号。     

无线传感器网络数据转发器硬件电路设计

为了建立传感器节点和远端上位控制机之间的通信链路,利用无线传感器网络技术,设计实现了无线传感器网络数据转发器的硬件电路。数据转发器由工控机、无线通信模块以及电源管理模块三部分组成。系统能源主要来自于太阳能蓄电池,为了达到无线传感器网络的低功耗要求,数据转发器采用休眠任务唤醒模式。实际应用表明,此系统具备低功耗、能量自给、可远距离控制的特点,具有广阔的应用前景。     

基于流媒体技术的网络化嵌入式视频监控系统

视频监控系统是日常生产生活中的重要辅助设备,提出并研究设计了基于流媒体技术的网络化嵌入式视频监控系统.以高性能嵌入式处理器、DSP处理器和嵌入式Linux操作系统为核心进行系统设计.系统通过DSP处理器进行视频信号的MPEG4数据压缩,在嵌入式处理器上采用流媒体技术通过网络传播实时视频流.详细论述了系统设计、硬件设计和软件设计,并给出了实际运行结果.     

基于LabVIEW的超音速校准风洞测控系统

随着航空技术的发展,需要建设超音速校准风洞,以满足特殊工况下的动态校准需求。基于TCP/IP协议,应用LabVIEW语言设计了一套超音速风洞测控系统,并详细介绍了系统的工作原理、硬件构成和软件设计思路。通过系统运行和性能测试,验证了该系统可以满足超音速条件下相关校准的使用要求。     

基于相位法的色标传感器动态响应特性测试与分析

目的 研究色标传感器的动态响应特性。方法 采用相位法测试色标传感器的动态响应特性;以嵌入式工业触摸屏为控制核心, 与色标传感器、 富士伺服电机、 伺服驱动器和编码器组成测试装置, 间接测试动态响应时间; 用MATLAB软件处理实验数据, 分析其动态特性。结果 在动态响应时间内, 根据基于触摸屏的相位法, 测得动态响应时间为2 ms, 其系统为一阶系统。结论 该测试方法简单可靠, 可以测出各种传感器的动态响应时间, 并可以判断其系统特性。     

Plug-n-Play Smart Sensor Network With Dynamic Web Service

In this paper, the authors present an implementation of a plug-n-play web sensor based on a web service approach, utilizing the extensible markup language, which is an open-source software, to exchange information and adopting a low-cost hardware. After an introduction to the web service technology, the problem of the dynamic services and one possible solution will be presented. The proposed solution allows us to have, at all times, an overview of the state of connected sensors and of the available services. Thus, when a new sensor is inserted in the network, its services are automatically “published” without reconfiguring the net; this is important with sensor networks, which are frequently upgraded. The sensor is presented in the framework of a hierarchical distributed system for metrological monitoring applications. Particular attention is devoted to synchronization problems among all composing devices of the proposed distributed system, taking into account the characteristics of main synchronization standards. Measurement results supplied by the sensors are made available as web services so that all users can build up their own applications. To show some preliminary results of the proposed distributed monitoring network, the monitoring of rms values in three-phase power networks was analyzed. A proper synchronization protocol was adopted in order to synchronize the different hardware sections of a sensor to perform a particular measurement.      

基于DSP的永磁同步电机调速系统设计

本文进行了24V／70W的永磁同步电机调速系统的硬件控制器设计和软件程序编写及相关实验。首先对DSP及其与电机控制相关的功能和结构进行介绍;然后说明永磁同步电机控制系统的硬件电路构成及设计方法,并给出系统的软件实现方法;最后对电机进行控制实验并给出实验结果,为实现永磁同步电机的各种控制策略奠定了实验基础。     

An Experimental Low-Cost, Low-Data-Rate Rapid Structural Assessment Network

In this paper, we present the design, implementation, and experimental evaluation of a wireless sensor network for real-time structural ldquohealthrdquo monitoring. We use simple custom-built gages to detect cracks in critical structural elements. The main data reports require no structural analysis for interpretation, have a low data rate, and are naturally resilient to loss. We show how a variety of low-cost, off-the-shelf data acquisition/communication devices can be used to support remote monitoring by a control center. The heterogeneous hardware is accommodated by the use of open technology standards and a software architecture that is portable, modular, and highly configurable. We present an experimental evaluation of our structural-assessment network done using a full-scale three-story reinforced concrete building that was tested under lateral forces emulating forces induced by earthquakes. Our results show that a set of 12 strategically positioned sensors achieved a 100% detection rate for cracks crossing sensors and a zero false-alarm rate (in the sense that all signals exceeding a preset threshold were traced to cracks exceeding a specified total width).     

位移传感器校验装置的研制

为解决大量程位移传感器检定过程中,传统人工手动检定法操作复杂、耗时长、测量准确度低的问题,研制了大量程位移传感器自动校验装置。详细介绍了该装置的硬件组成和软件设计,并阐述其创新特色。利用该装置对LVDT位移传感器进行校准,并对其测量不确定度进行评定。试验证明,该位移传感器校验装置测量准确度高、运行稳定性好,可有效提高检定效率,能够替代人工对位移传感器进行自动化检定,具有重要技术借鉴意义。     

机械设备状态监测虚拟仪器系统的研究

系统主要包含硬件和软件两大部分。其中硬件设计包含传感器、信号调理模块和数据采集卡,系统软件采用模块化编程,利用图形化编程语言LabVIEW进行模块化设计,实现对信号的采集与处理。系统的功能在简支梁实验台和机床变速箱上进行实验测试。结果表明,此系统人机界面友好,操作简单,大大提高设备在线监测诊断水平,为今后设备的监测诊断提供先进的分析工具。     

Application of carbon nanotube in wireless sensor network to monitor carbon dioxide

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Over the years, new discoveries have led to new applications, often taking advantage of their unique electrical properties, extraordinary strength and efficiency in heat conduction. Since industrialisation, human activities have resulted in steadily increasing concentrations of the greenhouse gases. Excess amount of carbon dioxide (CO₂) in living environment is toxic and unsuitable for human consumption. Thus, a need exists for accurate, inexpensive, long-term monitoring of environmental contaminants using sensors that can be operated on site. Over the past decade, many wireless sensor network (WSN)-based monitoring applications have been proposed. This article reviews the developments of sensing elements to monitor CO₂ in the environment. The cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science, as well as potential sensing element in wireless sensor technology. They exhibit extraordinary strength and unique electrical properties, and are efficient thermal conductors. The unique properties of CNT makes it a potential sensing element in the WSN technology.