基于LabVIEW的容栅扭矩测试系统设计

为完成工程中强磁场、强辐射、小空间等恶劣环境下的扭矩测量,设计并实现基于Lab VIEW的容栅扭矩测试系统,通过USB总线将Lab VIEW开发的上位机软件与以容栅传感器为核心的测试电路进行连接,测试电路利用转动轴前后两端携带正弦波信号的两组容栅,将对扭矩的测量转换为对两路正弦波信号相位差的测量,上位机软件对大容量的测试数据进行采集与处理。恶劣环境下测量转速在1 000~5 000 r/min时的转动轴扭角,以理想环境下的扭角测量值作为给定标准值,发现在1 000 r/min转速时相对误差最大,且相对误差6%。结果表明:该测试系统性能稳定可靠,测量准确度高,开发周期短,易于后期维护升级。     

基于无线传感器网络的防盗墓系统设计

针对盗墓形势日益严重,传统防盗墓措施已经不能解决"高科技盗墓技术"出现的问题,提出一种基于无线传感器网络的防盗墓系统设计方案。该系统采用动态选择工作节点和对岗哨节点进行阈值设置的方式降低了系统的功耗;采用改进型Infrastructure结构,解决室内多遮挡无线传输衰减问题;利用无线网桥,完成远程控制平台对偏僻墓穴的实时监测。测试结果表明:对盗墓者定位与轨迹跟踪结果精确,无线传输距离≥13 km,传输速率达16 Mb/s,数据传输性能良好。     

新型光纤扭矩测量方法

提出了利用光纤微弯损耗测量相对扭转角的原理,并建立了双向可测缠绕式光纤扭矩测量的理论模型,可以实现扭矩的实时动态测量。同时,提出了数字式无线信号传输的设计方案,可以解决旋转系统扭矩测量的信号传输问题。实验表明,在±50°的相对扭转角测量范围内,实现了灵敏度为0.383dB/1°的双向测量;动态测试条件下,测量精度在0.5%±0.22%之内。     

密闭式医用离心机的转速计量检测系统

针对当前密闭式医用离心机转速的计量检测难题,首次提出基于测振原理的密闭式医用离心机转速计量检测系统。该系统由测振传感器、信号调理电路、数据采集器和上位机测速系统组成,测振传感器实时测量密闭式医用离心机的振动信号,信号调理电路将振动信号放大、跟踪、滤波,数据采集器对信号高速采集然后通过USB传输到上位机测速系统,并基于最小条件的识别理论进行拟合、分析和处理。通过实验表明:基于测振原理和最小条件系统识别法的转速检测系统达到各种密闭式医用离心机转速的计量校准要求,该系统具有检测准确度高、自动化程度高、稳定性好和检测方便等优点,有很好的推广前景。     

基于LabVIEW的转速与扭矩测试系统设计

针对某3机架钢管轧机主轴的力学测量问题,采用扭矩传感器、通用的PCI板卡、计算机及LabVIEW软件等来构建测试系统,测定主轴转速、扭矩和实时功率.研究了通用PCI板卡的DLL连接方式以及系统构建中的软硬件设计,设计出具有实时测量、数据记录等功能的测量系统.该系统具有明显的成本优势,且通用性强,可应用于其他旋转机械的转速和扭矩测量.     

Zigbee技术在桥吊信号采集中的应用

为实现对现场桥吊的实时检测,本文设计了基于ZigBee无线通信技术的信号采集检测系统.通过传感器检测桥吊梁上的应变、温度等信号,应用CC2530模块来构造无线采集系统,并利用其内部电源监控电路检测电压.本文重点介绍采集节点的硬件设计及软件设计,实现了信号的采集与无线传输.     

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。     

基于物联网远程控制的上肢康复机器人系统研究

设计了一种基于物联网的远程控制上肢康复机器人系统。该系统通过位置传感器和扭矩传感器分别采集机器人机械臂的位置和力矩信息,由STM32控制器将其传输给上位机,经过处理后发送控制命令给下位机STM32控制器,从而控制康复机器人电机驱动;在客户端显示上肢康复机器人数据信息,同时通过互联网,服务器和客户端可以进行数据信息和视频信息传输,服务器端远程控制客户端患者进行康复训练。实验证明,该机器人系统可以实现不同模式下的康复训练,同时服务器端可以远程控制客户端,从而表明该上肢康复机器人系统的设计是可行和有效的。     

基于MSP430的空气环境质量监测系统设计

为了实现城市环境参数的分布式检测和集中统计管理,设计了一个空气环境质量监测系统。该系统分为上位机监控中心和下位机检测与传输终端两部分,下位机采用MSP430F149单片机作为控制核心,以温湿度传感器SHT11和PM2.5传感器进行数据采集。下位机有液晶显示,可以实时显示测量数据,并可手动设置报警值,检测数据同时通过Sim900无线模块传至监控中心。监控中心完成空气环境质量数据的统计管理,生成报表,便于管理部门做出决策。该系统已经在大学校园环境下进行了测试、应用,效果良好。     

基于无线传感网络带电预警系统的研究

基于无线传感网络提出并设计一种带电预警系统,通过测量电场值反演算电压状态,当测量值超过系统阈值时,便携式预警终端发出警示信号,同时将检测结果传输至上位机监测中心分析储存。结合MEMS电场传感机理,传感器探头结构采用三维布点,有效降低采集测量误差。建立低功耗、高性能ARM微控制器设计声光报警单元和无线发射模块,以ZigBee、GPRS为核心的无线传感网络网关节点,实现传感信号的同步采集和测量结果的可靠传输,解决复杂电磁环境下的抗干扰力问题。该系统的应用能准确获取空间某一点三维方向上电场的感应电荷,可靠获取高压输电线路的电压状态,及时报警,具有准确性强、便携、低功耗等特点。     

Wireless Acoustic Emission Sensor Network for Structural Monitoring

The paper presents a prototype wireless system for the detection of active fatigue cracks in aging railways bridges in real-time. The system is based on a small low-cost sensor node, called an AEPod, that has four acoustic emission (AE) channels and a strain channel for sensing, as well as the capability to communicate in a wireless fashion with other nodes and a base station. AEPods are placed at fracture-critical bridge locations. The strain sensor detects oncoming traffic and triggers the AEPod out of its hibernation mode. As the train stresses the fracture-critical member, acoustic emission and strain data are acquired. The data are compressed and filtered at the AEPod and transmitted off the bridge using cell-phone communication.     

A Mobile Host Approach for Wireless Powering and Interrogation of Structural Health Monitoring Sensor Networks

Wireless sensor networks (WSNs) for structural health monitoring (SHM) applications can provide the data collection necessary for rapid structural assessment after an event such as a natural disaster puts the reliability of civil infrastructure in question. Technical challenges affecting deployment of such a network include ensuring power is maintained at the sensor nodes, reducing installation and maintenance costs, and automating the collection and analysis of data provided by a wireless sensor network. In this work, a new "mobile host" WSN paradigm is presented. This architecture utilizes nodes that are deployed without resident power. The associated sensors operate on a mechanical memory principle. A mobile host, such as a robot or unmanned aerial vehicle, is used on an as-needed basis to charge the node by wireless power delivery and subsequently retrieve the data by wireless interrogation. The mobile host may be guided in turn to any deployed node that requires interrogation. The contribution of this work is the first field demonstration of a mobile host wireless sensor network. The sensor node, referred to as THINNER, capable of collecting data wirelessly in the absence of electrical power was developed. A peak displacement sensor capable of interfacing with the THINNER sensor node was also designed and tested. A wireless energy delivery package capable of being carried by an airborne mobile host was developed. Finally, the system engineering required to implement the overall sensor network was carried out. The field demonstration took place on an out-of-service, full-scale bridge near Truth-or-Consequences, NM.     

Use of Mixer-Torque Measurements as an Aid to Optimizing Wet Granulation Process

Instrumentation designed for monitoring the wet granulation process is described. A Hobart mixer was instrumented with a slip ring torque sensor using a voltage of 5 volts D.C. to excite a strain gauge bridge. An amplifier was used to magnify the low signal levels produced by the strain gauge bridge and the gain was set at 179.6 so that 2 volts equals 200 inch ounce. The output was recorded using a Bascom-Turner recorder. The relative dynamic torque, was measured in millivolts as a function of granulating fluid added and time to optimize the granulation process using the planetary mixer. The instrumentation described in this paper has considerable potential for optimization and validation studies for wet granulation procedures.     

Use of Mixer-Torque Measurements as an Aid to Optimizing Wet Granulation Process

Abstract

Instrumentation designed for monitoring the wet granulation process is described. A Hobart mixer was instrumented with a slip ring torque sensor using a voltage of 5 volts D.C. to excite a strain gauge bridge. An amplifier was used to magnify the low signal levels produced by the strain gauge bridge and the gain was set at 179.6 so that 2 volts equals 200 inch ounce. The output was recorded using a Bascom-Turner recorder. The relative dynamic torque, was measured in millivolts as a function of granulating fluid added and time to optimize the granulation process using the planetary mixer. The instrumentation described in this paper has considerable potential for optimization and validation studies for wet granulation procedures.     

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.     

基于DSP的智能家居无线网络节点的设计

 将无线传感器网络技术融入智能家居系统中,设计合理的网络节点成为智能家居系统的核心问题．在分析无线传感器网络节点结构基础上,提出以DSP 芯片TMS320F206为处理器、AT86RF230为无线通信芯片的无线传感器网络节点．充分考虑节能和扩展性的需求,采用节点定时打开与关闭的协议且打开与关闭的时间比为1∶99．试验表明该无线网络节点能满足低功耗、长传输距离、准确定位、抗干扰的要求．     

Multiaccess interference in a non-line-of-sight ultraviolet optical wireless sensor network

The concept of exploiting both the scattering properties and the absence of solar radiation in the "solar blind ultraviolet" spectral range for achieving a non-line-of-sight (NLOS) communication link for wireless sensor networks has been discussed in scientific literature. We address the issue of the multiaccess interference (MAI) that would be encountered in a simple and low-cost sensor network operating on the above NLOS principle, for different sensor node densities and traffic levels, and use a Poisson model for the sensor node distribution. A metric for evaluation and comparison of sensor node distribution scenarios is derived and used to discuss the performance limitations of NLOS wireless sensor networks operating in the solar blind ultraviolet spectrum. Guidelines for NLOS wireless sensor network design are outlined taking into consideration the cumulative effect of interference from distant sensor nodes, the expected number of hops, and the trade-off between node redundancy and node isolation. The significant contribution of network traffic control to system operability is demonstrated.     

不同车载工况下桥梁振动响应试验

基于梁的横向振动理论,利用奇异函数建立移动车载作用下单跨简支梁的振动响应方程,利用Mathcad软件求解得到了不同车载工况下桥梁振动的位移及加速度响应。以校内双车道玉泉桥为测试对象,在四个截面布设双排传感器,设计单一车载、同向双车载、相向双车载三种工况,每种工况设置4级车速,利用无线遥测动态应变测试分析系统采集各次试验中桥梁的加速度响应,分析了车载工况、车载速度对桥梁各截面加速度峰值的影响。研究表明：（1）实测同重量双车载同向运行时的振动响应小于单一车载作用下响应的两倍;（2）相同车速下,三种工况中单一车载作用下振动加速度峰值最小;（3）对于桥东两个截面,车速较小时,双车同向比双车相向时梁的加速度峰值高;而在车速较大时,情况则相反;（4）对于桥西两个截面,双车同向均比双车相向时的加速度峰值高;（5）速度较低时,三种工况下各截面的加速度峰值相差不大,而在速度较高时,三种工况下桥东的A截面的加速度峰值最大,桥西的D截面的最小。     

RF Energy Transmission for a Low-Power Wireless Impedance Sensor Node

The proper management of energy resources is essential for any wireless sensing system. With applications that span industrial, civil, and aerospace infrastructure, it is necessary for sensors and sensor nodes to be physically robust and power efficient. In many applications, a sensor network must operate in locations that are difficult to access, and often these systems have a desired operational lifespan which exceeds that of conventional battery technologies. In the present study, the use of microwave energy is examined as an alternate method for powering compact, deployable wireless sensor nodes. A prototype microstrip patch antenna has been designed to operate in the 2.4 GHz ISM band and is used to collect directed radio frequency (RF) energy to power a wireless impedance device that provides active sensing capabilities for structural health monitoring applications. The system has been demonstrated in the laboratory, and was deployed in field experiments on the Alamosa Canyon Bridge in New Mexico in August 2007. The transmitted power was limited to 1 W in field tests, and was able to charge the sensor node to 3.6 V in 27 s. This power level was sufficient to measure two piezoelectric sensors and transmit data back to a base station on the bridge.      

基于计算机视觉人行桥挠度影响线非接触式识别

该文将便携式相机与无线传感器结合,开发了一种人致挠度影响线非接触式识别系统,避免了传统识别方法需要长时间阻断交通、耗费大量人力物力等不足,可用于运营状态下的桥梁影响线识别。通过便携式相机获取桥上行人行为,引入遮挡模型改进YOLO算法识别桥上行人,跟踪目标行人坐标变化得到行人位置信息,结合无线传感器得到的行人荷载作为结构输入数据。通过视觉识别技术跟踪结构行为获得人行荷载作用下的位移响应作为结构输出数据。根据结构输入输出数据反算人行荷载作用下桥梁挠度影响线。对初始影响线进行高阶滤波处理,消除环境和其他因素干扰,然后利用多项式分段拟合实测桥梁影响线进而得到具有准静态特性的挠度影响线,可为结构工程师准确高效地提供桥梁损伤检测依据。