基于ZigBee的客车环境监测实验系统设计

为更方便地获取客车车厢内部环境参数,设计基于ZigBee无线传感器网络的客车环境参数监测实验系统.整个实验系统主要由多个ZigBee无线采集模块、路由器、协调器以及上位机软件组成,协调器汇集系统中分布于空间不同位置的多个采集节点采集的车厢内部温湿度、CO浓度和气压等数据,并实时传送至上位车辆管理计算机,上位机程序采用LabVIEW编写.实验表明:所设计的无线传感器网络监测实验系统使用方便、性能良好,达到预期设计的要求.     

基于ZigBee与GPRS的远程温湿度监测系统设计

根据环境监测中对远程温湿度数据监测的要求,针对现有监测系统布线复杂或通信距离不足、成本过高的问题,采用工业级ARM7微处理器并运用温度传感器和湿度传感器对温湿度数据进行采集。此外采用ZigBee技术组建了无线Mesh网,完成了中控计算机与无线温湿度传感器之间的通信,并可通过ZigBee转GPRS网关将温湿度数据传输到GPRS网络,完成了温湿度的远程监测,经实际验证本系统能够可靠、快速的组建温湿度监测系统。     

基于DSP的高速动车组车内噪声测试系统设计

为满足高速动车组车内噪声试验的需求,设计一种基于DSP的噪声测试系统,对测试系统的设计方案以及软硬件实现进行介绍。系统由控制部分和运算部分组成:控制部分以高性能、低功耗的基于ARM Cortex-M3内核的微控制器STM32F103ZET6为核心,扩展了A/D采集模块、NAND Flash存储模块以及蓝牙通信模块;运算部分以TI公司的低功耗DSP芯片TMS320VC5509A作为核心,负责对采集的噪声数据进行实时处理,并把结果交给ARM发送给上位机,以实现对试验效果的实时观察;ARM与DSP通过双端口RAM相连接,使得两种处理器间的频率差异得到解决并能有效地实现数据交换。实验证明:基于DSP的噪声测试系统能很好地满足高速动车组车内噪声试验对噪声数据采集和实时处理的需求。     

多运行工况下高速动车组走行系统多位振动特性分析

走行系统是影响高速动车组运行安全的关键系统构成,掌握走行系统不同工况下不同部位或设备的振动特性,对实现高速动车组走行系统安全状态检测、健康监测、故障诊断与在线预警具有重要意义。该文基于高速动车组运行实测数据,详细地分析高速动车组车体及转向架多个部件或部位在直线、曲线及道岔通过不同运行工况下振动特性演变规律。首先对数据来源、实验方案及现有高速列车振动特性评价方法进行阐述,进一步分析车体振动特性及转向架多位振动特性,重点涵盖轴箱、构架、齿轮箱和电机关键部件。分析结果对于掌握高速动车组关键设备或部位动态响应及其变化规律具有指导与支撑作用,同时为高速列车关键部件振动性能评价、部件维护检修等提供参考依据。     

一种基于ZigBee组网技术的山体滑坡监测系统设计

山体滑坡是一种常见的具有较强破坏性的自然灾害,该文提出了通过ZigBee技术将土壤含水量、空气温湿度、加速度及位移等传感器构成网络信号采集终端,终端数据利用GPRS传输到上位机,对山体滑坡灾情进行精确监测,该系统在黔江区易滑坡地带进行系统联机测试,各传感器采集数据正常,ZigBee组网稳定,数据传输正确、完整,为山体滑坡预警提供了技术支持。     

基于ZigBee无线传感器网络技术的双孢菇生长环境监测系统的设计

为有效实现对双孢菇生长环境信息的在线监测与实时传输,提高双孢菇种植管理的网络化和智能化水平,文章设计一种基于ZigBee无线传感器网络技术的双孢菇生长环境信息监测系统,详细阐述其总体设计思路和各组成部分的软硬件设计及工作流程。经实验结果表明:该系统传感器数据采集准确、监测功能良好、待机时间长,能够实时准确地监测双孢菇生长环境信息,具有良好的实用价值与推广意义。     

基于ZigBee的温度监测系统

为了实现温度的实时监测,提出了一种基于无线传感器网络的的温度监测系统,介绍了基于温度检测系统的设计思想和实现过程。系统以内嵌51兼容单片机的射频收发芯片CC2530为核心,采用数字式温度传感器DS18B20,应用传感技术、无线通信技术及计算机技术,实现了基于ZigBee的温度监测。     

一种基于ZigBee的家居环境质量评测系统的设计

随着人们生活水平的不断提高,环境污染问题显得越发突出,家居的环境也越来越重要。传统的分布式环境监测,扩展性差,布线麻烦,影响美观,线路易被老化,或腐蚀。针对传统环境监测系统布线复杂,可拓展性差的不足,文章将ZigBee技术与传感器网络相融合,设计了一套基于ZigBee的家居环境监测系统。系统通过ZigBee终端节点采集居室传感器数据信息,在居室内部建立ZigBee无线网络,将传感器信息由ZigBee协调器模块传给系统的主控器,并最终将数据显示到QT界面中。     

开闭所、环网柜防潮除湿应用研究

该文设计了一种基于Zig Bee无线传感器网络技术的冷凝温湿度监控器,根据系统对开闭所、网环柜温湿度传感器节点采集到的数据和预设的电气最佳工作环境的阈值范围进行分析,系统判断开闭所、网环柜的环境参数是否适宜,从而控制管理机制中的冷凝器、风扇等的状态,自动调节温室环境。该系统不仅可以准确地监测开闭所、网环柜环境等性能指标,还可以实现参数的动态调整,可降低人工成本,实现精细化管理。     

便携式温湿度舒适性测试仪研究

为了解列车运行时客室内温湿度的动态变化以及该变化对乘客舒适性的影响,研究设计一种便携式温湿度舒适性实时测试系统。通过在高速列车实测温湿度数据和乘客调查问卷的统计分析基础上,给出适用于我国高速列车的温湿度舒适性评价指标。系统以STM32系列处理器和数字式温湿度传感器SHT21为核心,采用模块化设计,由电源模板、温湿度测量模块、存储模块和LCD显示模块组成。实验表明该系统可满足高速列车客室内温湿度动态变化及乘客温湿度舒适性的测试要求。     

药品冷链监控系统数据传输程序设计

目的基于无线射频识别(RFID)技术的药品冷链监控系统数据传输程序设计。方法首先解决监控对象的温湿度信息采集和分布式多标签数据读取的冲突问题,然后解决数据由传感器经读写器、车载GPRS模块至中心服务器的数据传输通讯问题。结果基于UDP网络传输协议平台,设计开发了CRC校验码和防冲突算法通讯接口程序。结论实现了数据采集传输的实时性、完整性和准确性,为进一步开发冷链监控系统奠定了基础。     

Risk-based reconfiguration of safety monitoring system using dynamic Bayesian network

To prevent an abnormal event from leading to an accident, the role of its safety monitoring system is very important. The safety monitoring system detects symptoms of an abnormal event to mitigate its effect at its early stage. As the operation time passes by, the sensor reliability decreases, which implies that the decision criteria of the safety monitoring system should be modified depending on the sensor reliability as well as the system reliability. This paper presents a framework for the decision criteria (or diagnosis logic) of the safety monitoring system. The logic can be dynamically modified based on sensor output data monitored at regular intervals to minimize the expected loss caused by two types of safety monitoring system failure events: failed-dangerous (FD) and failed-safe (FS). The former corresponds to no response under an abnormal system condition, while the latter implies a spurious activation under a normal system condition. Dynamic Bayesian network theory can be applied to modeling the entire system behavior composed of the system and its safety monitoring system. Using the estimated state probabilities, the optimal decision criterion is given to obtain the optimal diagnosis logic. An illustrative example of a three-sensor system shows the merits and characteristics of the proposed method, where the reasonable interpretation of sensor data can be obtained.     

On-off控制对高速动车组综合动力学性能的影响分析

利用ADAMS-Matlab联合仿真的方法研究了on-off半主动控制对高速动车组的横向平稳性、运动稳定性和安全性的影响。根据国内某型号高速动车组的参数,利用多体动力学软件ADAMS/Rail建立了满载工况下的单车动车组模型。随后,运用ADAMS-Matlab联合仿真的方法对被动控制和on-off半主动控制条件下的动车组模型进行了仿真分析,仿真考虑了不同运行速度和不同线路条件等工况。最后,分别计算了两种控制条件下高速动车组模型的横向平稳性、运动稳定性和安全性能。从分析结果可知：与被动控制相比,on-off控制下车辆的横向平稳性指标可大幅提升35.5%,但非线性临界速度降低了16.6%,高速运行工况下的安全性指标也严重下降。因此,on-off控制策略在高速动车组上应用时存在严重缺陷,需要对其进行改良方可应用。     

An integrated method for comprehensive sensor network development in complex power plant systems

The rapid advancement of powerful monitoring devices and computers permits one to design a comprehensive sensor network as the foundation of an efficient plant condition monitoring and diagnosis system. For the development of such a comprehensive sensor network in complex power plant systems, the work presented here describes the rationale and implementation of an integrated method incorporating a structural system hierarchy and a functional system hierarchy, a fault–symptom matrix, sensor selection criteria, use of a sensor installation feasibility study, and advanced instrumentation steps. In selecting instrumentation to use we include the state of the art technologies concerning data processing and data integration as a means of extending the plant's feasible diagnostic coverage. The application of the design technique described here to the specific example component of the turbine generator demonstrates how each step of the presented method contributes to completion of the sensor network development in a systematic way.     

Assessment of optical emission analysis for in-process monitoring of powder bed fusion additive manufacturing

ABSTRACT

Developing methods which allow real-time monitoring of powder bed fusion (PBF) additive manufacturing (AM) processes is key to enabling in situ assessments of build quality (e.g. lack of fusion and porosity). Here, we investigate the use of optical emission spectroscopy and high-speed (100?kHz) measurement of select wavelength emissions, based on a line-to-continuum approach, to determine if a correlation between PBF AM process inputs, sensor outputs, and build quality exists. Using an open protocol system interfaced with a 3D Systems ProX 200 machine, sensor data were synchronised with the scanner position and the laser state during the buildup of Inconel-718 components under varying powers, scan speeds, and hatch spacing parameters. Sensor measurements were then compared against post-build computed tomography scans. We show evidence that sensor data, when combined with appropriate analyses, are related to both processing conditions and build quality.     

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.     

Challenges in the capture and dissemination of measurements from high-speed networks

The production of a large-scale monitoring system for a high-speed network leads to a number of challenges. These challenges are not purely technical but also socio-political and legal. The number of stakeholders in such monitoring activity is large including the network operators, the users, the equipment manufacturers and, of course, the monitoring researchers. The MASTS project (measurement at all scales in time and space) was created to instrument the high-speed JANET lightpath network and has been extended to incorporate other paths supported by JANET(UK). Challenges the project has faced included: simple access to the network; legal issues involved in the storage and dissemination of the captured information, which may be personal; the volume of data captured and the rate at which these data appear at store. To this end, the MASTS system will have established four monitoring points each capturing packets on a high-speed link. Traffic header data will be continuously collected, anonymised, indexed, stored and made available to the research community. A legal framework for the capture and storage of network measurement data has been developed which allows the anonymised IP traces to be used for research purposes.     

Interrogation of a Long Period Grating Fiber Sensor With an Arrayed-Waveguide-Grating-Based Demultiplexer Through Curve Fitting

Interrogation of a long period grating (LPG) fiber sensor with an arrayed-waveguide-grating (AWG)-based demultiplexer through curve fitting is investigated and experimentally demonstrated. In the interrogation system, the measured light intensities from the output of the AWG are used to reconstruct the selected resonant dip of the LPG sensor through curve fitting in the form of a linear combination of Gaussian functions. By monitoring the changes of the reconstructed LPG spectrum, including the center wavelength shift and the minimum attenuation variation, the sensor signals can be interrogated with good accuracy in real time. The center wavelength is obtained by calculating the first-order derivative of the fitting function. The minimum attenuation is obtained directly from the reconstructed spectrum. Since the interrogation system demonstrated is based on an all-solid-state optical device, it offers the advantages of compact size and high-speed interrogation with high potential for integration.      

高速动车组构架载荷特征研究

高速动车组转向架构架不仅承受和传递来自一系和二系悬挂系统的载荷,而且承受来自电机、齿轮箱以及牵引制动等部件产生的载荷,因此,这些载荷引起的构架结构疲劳可靠性受到广泛关注,但这些与构架结构可靠性密切相关的载荷却少有研究。该文提出解耦和降维法识别某型高速动车组构架轴箱弹簧垂向载荷、定位节点横向载荷、电机垂向和横向载荷、齿轮箱垂向载荷以及抗侧滚装置载荷,制作测力构架并首次实际线路全面测试该型动车组运行过程中载荷引起的应变信号,列车最高试验速度368 km/h。对测试数据进行处理和分析,获得了高速动车组运行工况下这些载荷的时间历程,分析了载荷的时域和频域特征,给出了轴箱弹簧载荷峰值与运行速度之间关系。采用雨流计数法统计了载荷峰谷值和频次,获得了不同速度等级下载荷谱,给出了构架200万次试验条件下的等效载荷。结果表明:轴箱弹簧载荷、定位节点横向载荷、电机载荷以及齿轮箱载荷受列车运行速度和轨道激扰影响明显,抗侧滚装置受列车速度和曲线条件影响明显,轨道随机激扰对抗侧滚装置载荷影响不明显。钢轨现场焊接接头不平顺使得轴箱弹簧承受明显的冲击载荷并作用于构架,且该冲击载荷频率一般为49 Hz~51 Hz。列车正线行驶时,轴箱弹簧载荷最大动荷系数0.23,构架侧滚和浮沉载荷系数最大值分别为0.14和0.1。电机和齿轮箱载荷峰值接近标准JIS E4208给出的动载荷值。幅值频率积可直观地表示中高频范围内载荷幅值变化特性。该文研究结果对高速动车组动力学研究和构架结构设计及疲劳试验等具有重要意义。     

Formation of Uniform Water Microdroplets on Wrinkled Graphene for Ultrafast Humidity Sensing

Portable humidity sensors with ultrafast responses fabricated in wearable devices have promising application prospects in disease diagnostics, health status monitoring, and personal healthcare data collecting. However, prolonged exposures to high‐humidity environments usually cause device degradation or failure due to excessive water adsorbed on the sensor surface. In the present work, a graphene film based humidity sensor with a hydrophobic surface and uniformly distributed ring‐like wrinkles is designed and fabricated that exhibits excellent performance in breath sensing. The wrinkled morphology of the graphene sensor is able to effectively prevent the aggregation of water microdroplets and thus maximize the evaporation rate. The as‐fabricated sensor responds to and recovers from humidity in 12.5 ms, the fastest response of humidity sensors reported so far, yet in a very stable manner. The sensor is fabricated into a mask and successfully applied to monitoring sudden changes in respiratory rate and depth, such as breathing disorder or arrest, as well as subtle changes in humidity level caused by talking, cough and skin evaporation. The sensor can potentially enable long‐term daily monitoring of breath and skin evaporation with its ultrafast response and high sensitivity, as well as excellent stability in high‐humidity environments.