智能传感器Imote2运行环境的安装解析

介绍了使用无线传感器网络进行环境监测的三大优势,探讨了智能传感器Imote2运行环境的安装解析,指出智能传感器Imote2具有高效的计算能力和无线通信能力,为传感器网络领域的研究提供了硬件基础。     

钢管混凝土拱桥吊杆损伤分布式识别

随着工程结构的日益大型化和复杂化,结构损伤检测时需要布置大量的传感器.传统的集中采集和处理的技术将难以胜任海量数据的处理要求.有利于降低成本,密集布置的无线智能传感器就成为大型结构健康监测系统的最佳选择.采用分布式损伤识别方法是密集布排的无线传感测试系统的必然要求.针对拱桥吊杆损伤的问题提出应用于无线传感网络的分布式识别技术.以一混凝土钢管拱桥为实验平台,松动吊杆端部锚具制造不同程度的松弛损伤,对损伤前后拱桥进行振动测试,按照网络拓扑情况,利用功率谱密度曲率差法进行损伤识别分析.结果表明:分布式损伤识别技术能够成功识别拱桥吊杆损伤,并且该方法可以应用到其他密集布排无线传感器的大型复杂结构的健康监测和检测中.     

无线土体变形监测传感器验证

基于Flex传感器进行土体变形监测,建立了室内模型箱试验,测试Flex无线土体变形监测传感器的测量性能.通过边坡模型的加载试验,验证了Flex无线土体变形监测传感系统的实用性,同时证明了Flex无线土体变形监测传感器具有足够的精度.     

基于分布式传感网络的结构模态识别方法

结构的模态参数识别是结构健康监测系统的基本任务。随着工程结构的日益大型化和复杂化,振动测试时需要布置大量的传感器。传统的集中采集和处理技术将难以胜任海量数据的处理要求,采用无线智能传感器的结构健康监测系统正是应运而生的新方向,而分布式采集和处理是其特点。在无线智能传感网络拓扑结构中采用分布式算法求解结构整体振型,利用随机子空间法识别各子结构模态,结合粒子群优化算法调整子振型获取结构整体振型。通过混凝土钢管拱桥模型试验验证了分布式算法的可行性,并利用模态置信度(MAC)对比分析了由分布式模态识别方法和集中式模态识别方法得到的结果,结果表明两种算法吻合较好。     

边坡柔性传感器验证

使用Flex传感器结合蓝牙无线传输技术来制造边坡土壤沉降传感系统,以监测边坡土壤沉降.在研究中,通过校准测试来解释Flex弯曲传感器的输出信号与弯曲角度变化之间的关系.并通过斜率模型加载试验证明了Flex弯曲传感器具有适当的系统精度和实用性.该研究的主要创新是使用新型传感器结合蓝牙无线传输技术形成监测系统,这被证实能够...     

无线传感器网络在悬臂梁试验中的应用

运用TinyOS软件对无线传感器编程,使节点构成无线传感器网络,并将其应用于大型土木结构的健康监测.首先介绍了无线传感器网络的特征和TinyOS操作系统,然后叙述了采用Micaz构成的无线传感器网络进行悬臂梁模态频率测试的过程,最后讨论了程序编写和试验方法的有关问题,并将试验结果与有线传感器及有限元分析结果进行了比较.结果表明,该试验方法是有效可行的.     

基于传感技术的土体位移监测系统

基坑建设中土体位移的监测十分关键.基于Flex弯曲传感技术和无线蓝牙技术设计并制作了1种土体位移传感器,利用Flex传感器的角度测量原理,利用标定试验获取传感器弯曲角度与信号变化之间的线性关系,结果表明:该传感器测量的最大量程为60o,灵敏度介于0.5o～0.7o之间.基于室内模型加载试验进行传感器性能验证,结合标定试验的位移结果,与传统位移计的结果对比验证,发现两者位移高度一致.该Flex位移传感器可对基坑工程的位移、沉降等参数进行实时无线监测,为岩土监测提供了1种新方法.     

面向WSN协议的自动化测试系统研究与设计

现有无线传感器网络(WSN)协议一致性测试自动化方法尚不完善,给测试有效性和客观性带来不利影响,本文提出一种一致性测试的自动化方法的体系结构,由测试用例生成器和测试结果分析器组成,并基于该体系结构实现了一致性自动化测试系统。在实际应用中也证实了本方法的适用性和有效性。     

基于无线传感器网络的矿井环境监测系统研究

煤矿井下环境恶劣,给煤矿安全生产和矿工的身心健康带来很大威胁,建立矿井环境监测系统对保证矿井安全生产具有重要的意义。本文将无线传感器网络技术引入矿井环境监测系统方案中,设计了基于无线传感器网络的矿井环境监测系统模型,并对方案中的关键技术进行可行性分析。分析表明,基于无线传感器网络的矿井环境监测系统具有实用性和可行性。     

无线传感器网络在桥梁健康监测中的应用

阐述了结构健康监测系统的基本概念和构成体系.通过无线传感器网络的建设,对桥梁结构进行静载试验和动载试验,利用静态测试数据的传感技术和实时动态监测的信号来对结构损伤部位进行分析,使无线传感器监测系统满足结构的健康监测要求.     

大体积混凝土结构长期应变监测系统

桥梁健康监测系统是近年应用于桥梁管理与维护的一项新技术,具有重要的工程价值。无线振弦传感器具有抗干扰强,精度高,传输距离远等特点,广泛应用于大体积混凝土结构中振动、应力等动态物理量监测。本文主要论述了桥梁无线应变监测系统结构、无线振弦传感器工作原理,设计了振弦传感器内部的激振电路及测频电路,以及无线通讯模块,同时给出了内部软件的设计,分析了无线振弦传感器的特性。无线的设计极大的方便了振弦传感器的使用,通过工程实际应用显示,本文设计的基于正弦传感器的桥梁无线应变监测系统稳定、质量可靠、测量数据迅速准确。     

Wireless Monitoring of a Multispan Bridge Superstructure for Diagnostic Load Testing and System Identification

Abstract: This article focuses on the deployment of a wireless sensor system (WSS) developed at Clarkson University for structural monitoring purposes. The WSS is designed specifically for diagnostic bridge monitoring, providing independent conditioning for accelerometers, strain transducers, and temperature sensors in addition to high‐rate wireless data transmission and is capable of supporting large‐scale sensor arrays. A three‐span simply supported structure was subjected to diagnostic load testing as well as ambient vibration monitoring. A total of 90 wireless and several wired sensors, including accelerometers and strain transducers were used in the deployment. Strain measurements provided capacity and demand characteristics of the structure in the form of neutral axis locations, load distributions, and dynamic allowances which ultimately produced an inventory and operating load rating for the structure. Additionally, modal characteristics of the structure, including natural frequencies and mode shapes, were derived from measured accelerations and discussed briefly.     

Wireless sensor networks as part of a web-based building environmental monitoring system

The presented research shows how advanced wireless sensor technology can be used by engineers to monitor conditions in and around buildings. The objective is split into three different tasks. First, wireless sensor hardware is programmed to process signals from sensors and transmit the data in a suitable format. This task was accomplished through an open-source operating system and a programming language designed specifically for wireless sensor hardware. The second task involved the processing of signals sent by the wireless sensor nodes. In this application, a Java program was written that deciphered messages transmitted from a wireless receiver over a computer's serial port and then placed the data in a database. The structure of that database is discussed to help identify the key pieces of information that are needed to make use of the data. The third piece of the proposed monitoring system is an interface to review the data. A Web-based system was developed that allows a user to mine the database using parameters such as the type of data, location of sensor, and the time of data acquisition. It is anticipated that this research will demonstrate the potential of using wireless sensor networks for monitoring buildings.     

Development of a Cost‐Effective Wireless Vibration Weigh‐In‐Motion System to Estimate Axle Weights of Trucks

Truck weight data plays an important role in weight enforcement and pavement condition assessment. This data is primarily obtained through weigh stations and Weigh‐In‐Motion (WIM) stations which are currently very expensive to install and maintain. This article presents results of the implementation of an inexpensive wireless sensor‐based vibration WIM system. The proposed wireless sensor network (WSN) consists of acceleration sensors that report pavement vibration; vehicle detection sensors that report a vehicle's arrival and departure times; and an access point (AP) that synchronizes all the sensors and records the sensor data. The article also describes a new method for speed compensation, an energy‐efficient algorithm (adaptive sampling method) to increase battery life, and a new modeling procedure to estimate gross vehicle weights. The system deployed near a conventional WIM system on I‐80W in Pinole, CA passed the accuracy standards for WIM systems and outperformed a nearby commercial WIM station, based on conventional technology.     

A Synchronized Wireless Sensor Network for Experimental Modal Analysis in Structural Health Monitoring

Abstract: Structural health monitoring aims to provide an accurate diagnosis of the condition of civil infrastructures during their life span using data acquired by sensors. Wireless sensor networks represent a suitable monitoring technology to collect reliable information about the structure's condition, replacing visual inspections, and reducing installation and maintenance time and costs. This article introduces a time synchronized and configurable wireless sensor network for structural health monitoring enabling a highly accurate identification of the modal properties of the monitored structure. The wireless sensor nodes forming the network are equipped with a 3‐axis digital accelerometer and a temperature and humidity sensor. The implemented Medium Access Control layer time synchronization protocol (μ‐Sync) ensures a highly accurate synchronicity among the samples collected by the nodes, the absolute error being constantly below 10 μs, also when high sampling frequency (up to 1 kHz) and extended sampling periods (up to 10 minutes) are applied. The experimental results obtained on a wooden model bridge, compared with those derived from acceleration signals acquired by high‐quality wired sensors, show that the so synchronized wireless sensor nodes allow a precise identification of the natural frequencies of vibration of the monitored structure (1% maximum relative difference).     

温度监测系统的设计及在屋顶绿化节能效果检测中的应用

为了监测屋顶绿化的节能效果,设计并实现了屋顶绿化温度监测系统。该系统可以实现现场数据的实时采集,并且采用无线数据传输模块,可以对屋顶绿化的热工性能远程监测,通过该系统可以得到种植不同植物屋顶的热工参数。采用多项式最小二乘法对温度传感器的模拟量信号与温度值间的关系进行拟合,提高了系统的采样精度。     

新型无线火灾报警系统的设计与应用

介绍无线火灾探测器的优点,然后依托具体应用需求,设计出一种基于无线传感网络的新型报警系统。从系统设计原理、软硬件平台、时间同步和数据传输等关键技术等方面对该报警系统进行介绍。通过实物测试和系统运行,证明了该系统数据通信稳定、探测精度高,具备早期预警和灾害现场提取数据的功能。     

轮胎压力智能检测与预警系统的设计

在充分考虑降低轮胎压力检测系统的功耗,减小轮胎压力检测系统的质量和体积的基础上,应用传感器技术、微电子技术、嵌入式技术和射频通信技术等设计了一种新型的轮胎压力智能检测与预警系统;在系统设计上采用模块化思想,主要包括了信号采集、基站与端机的设计、射频通信模块的设计、显示和键盘模块的设计和数据处理等;轮胎压力智能检测和预警系统可以明显的提高汽车行驶的平缓性、安全性和舒适性,具有非常广泛的应用前景.     

基于自适应动态惩罚遗传算法的桥梁监测无线测点优化研究

针对桥梁监测的无线测点优化布置问题,提出一种基于自适应动态惩罚函数的改进广义遗传算法。首先针对无线传感器数量固定和通信距离有限的典型特征将桥梁监测无线测点优化布置表达为约束优化问题,无线传感器的数量和极限传输距离作为优化问题的约束;其次构建了一种能够根据解的偏离程度和种群中高适应度个体数量自动调整惩罚力度的自适应动态惩罚函数;然后采用精英保存机制和末位淘汰策略对基于二重结构编码的广义遗传算法进行了改进;最后利用一大跨悬索桥对该方法进行了验证,并进一步讨论了自适应动态惩罚函数对解的有效性和收敛速度的影响。结果表明:提出的自适应动态惩罚函数能够根据种群的特征自动改变惩罚尺度,保证无线传感器之间的距离小于极限通信距离,同时将无线数据传输距离对桥梁监测信息获取的影响降到最低;改进的广义遗传算法具有很强的全局快速寻优能力,能够快速搜索到全局最优解,优化结果不仅能够满足无线传感网络数据传输距离的要求,还能最大化无线测点的信息获取能力。     

Mobile Agent Computing Paradigm for Building a Flexible Structural Health Monitoring Sensor Network

Abstract: Wireless structural health monitoring research has drawn great attention in recent years from various research groups. While sensor network approach is a feasible solution for structural health monitoring, the design of wireless sensor networks presents a number of challenges, such as adaptability and the limited communication bandwidth. To address these challenges, we explore the mobile agent approach to enhance the flexibility and reduce raw data transmission in wireless structural health monitoring sensor networks. An integrated wireless sensor network consisting of a mobile agent‐based network middleware and distributed high computational power sensor nodes is developed. These embedded computer‐based high computational power sensor nodes include Linux operating system, integrate with open source numerical libraries, and connect to multimodality sensors to support both active and passive sensing. The mobile agent middleware is built on a mobile agent system called Mobile‐C. The mobile agent middleware allows a sensor network moving computational programs to the data source. With mobile agent middleware, a sensor network is able to adopt newly developed diagnosis algorithms and make adjustment in response to operational or task changes. The presented mobile agent approach has been validated for structural damage diagnosis using a scaled steel bridge.