High-g Shocking Testing of the Martlet Wireless Sensing System

This article reports the latest development of a wireless sensing system,named Martlet,on high-g shock acceleration measurement.The Martlet sensing node design is based on a Texas Instruments Piccolo microcontroller,with clock frequency programmable up to 90 MHz.The high clock frequency of the microcontroller enables Martlet to support high-frequency data acquisition and high-speed onboard computation.In addition,the extensible design of the Martlet node conveniently allows incorporation of multiple sensor boards.In this study,a high-g accelerometer interface board is developed to allow Martlet to work with the selected microelectromechanical system(MEMS)high-g accelerometers.Besides low-pass and highpass filters,amplification gains are also implemented on the high-g accelerometer interface board.Laboratory impact experiments are conducted to validate the performance of the Martlet wireless sensing system with the high-g accelerometer board.The results of this study show that the performance of the wireless sensing system is comparable to the cabled system.

Construction of T-Ring:A Novel Integrated Radio Testing Ring

Outfield testing is an effective measure to check the performance of wireless networks and facilities.Current outfield testing environment has inherent fluctuation due to the wireless propagation condition and has other disadvantages such as nonsupport for multiple scenarios,and low-level yet high-cost auto-control capability.In this paper,the conception of a radio testing environment,known as T-Ring(Integrated-Testing Ring),is proposed.It is based on a novel fitting degree evaluation frame.The testing ring can achieve high level of fitting degree to the real network so that the fluctuation of the wireless environment will be under control or even eliminated.This paper will choose some typical performance indicators and obtain corresponding statistical data in both the real network and system level simulation.A complete set of procedures is also given in this paper to evaluate the fitting degree of testing results and simulation results.It proves that the simulation highly fits to the real network and the simulation configuration can be used to construct the testing ring.At the same time,the advanced radio testing ring integrates multiple radio access technologies,scenarios and facilities from different manufacturers.It can improve the efficiency of wireless outfield testing and lower the cost of operators and manufacturers.

Challenges in Qualitative Accelerated Testing of WSN Hardware

Internet of Things (IOT) is a conceptual vision to connect things in order to create a ubiquitous computing world. In order to create such an ever-present network, a simple, reliable, and cost-effective technology is crucial. Wireless sensor network (WSN) is an important wireless technology that has wide variety of applications and provides unlimited future potentials for IOT. Since WSNs in IOT will be used in varying and challenging applications and environments, reliability and reliability testing of WSN hardware becomes extremely important. In accelerated reliability testing, test stresses are increased to cut down the time required to obtain a weakening effect similar to one resulting from normal service conditions in the field. This paper introduces three common difficulties that engineers may experience in qualitative accelerated testing of WSN devices: 1. Challenges in use of standard accelerated tests, 2. Challenges in component-level testing, and 3. Challenges in testing of prototypes. The paper will also introduce examples from real life reliability research and accelerated tests to clarify the presented challenges.

Location Verification Systems in Emerging Wireless Networks

As location-based techniques and applications have become ubiquitous in emerging wireless networks, the verification of location information has become more important. In recent years, there has been an explosion of activity related to lo- cation-verification techniques in wireless networks. In particular, there has been a specific focus on intelligent transport systems because of the mission-critical nature of vehicle location verification. In this paper, we review recent research on wireless location verification related to vehicular networks. We focus on location verification systems that rely on for- mal mathematical classification frameworks and show how many systems are either partially or fully encompassed by such frameworks.

Time Delay Characteristic of Industrial Wireless Networks Based on IEEE 802.15.4a

The IEEE 802.15.4a standard provides a framework for low-data-rate communication systems,typically sensor networks.In this paper,we established a realistic environment for the time delay characteristic of industrial network based on IEEE 802.15.4a.Several sets of practical experiments are conducted to study its various features,including the effects of 1） numeral wireless nodes,2） numeral data packets,3） data transmissions with different upper-layer protocols,4） physical distance between nodes,and 5） adding and reducing the number of the wireless nodes.The results show that IEEE 802.15.4a is suitable for some industrial applications that have more relaxed throughput requirements and time-delay.Some issues that could degrade the network performance are also discussed.

Design and realization of lamp life test instrument

This paper introduces an instrument and method for lamp life test. The design of the instrument is divided into three steps： the oyerall design scheme, hardware circuit design and host machine programming. The instrument contains luminance and temperature sensors which can measure luminance of the lamp lighting and environment temperature in the instrument body. Then, the measure data can be transmitted to PC via the wireless transceiver modules for real-time monitoring. The luminance degradation curve based on the measure data is used to reckon the life of the lamp. In the end, the method for processing measurement data is given.

Design and application of wireless signal strength measurement system on the near-ground

The wireless communication system's performance is greatly constrained by the wireless channel characteristics,especially in some specific environment.Therefore,signal transmission will be greatly impacted even if not in a complicated topography.Testing results show that it is hardly to characterize the radio propagation properties for the antenna installed on the ground.In order to ensure a successful communication,the radio frequency(RF)wireless signal intensity monitor system was designed.We can get the wireless link transmission loss through measuring signal strength from received node.The test shows that the near-ground wireless signal propagation characteristics still can be characterized by the log distance propagation loss model.These results will conduce to studying the transmission characteristic of Near-Earth wireless signals and will predict the coverage of the earth's surface wireless sensor network.

A Novel Approach for Fault Diagnosis in Wireless Sensor Networks

The following article has been retracted due to special reason of the author. This paper published in Vol.5 No. 2, 2013, has been removed from this site.

Development of a Wireless Environmental Data Acquisition Prototype Adopting Agile Practices: An Experience Report

The traditional software development model commonly named “waterfall” is unable to cope with the increasing functionality and complexity of modern embedded systems. In addition, it is unable to support the ability for businesses to quickly respond to new market opportunities due to changing requirements. As a response, the software development community developed the Agile Methodologies (e.g., extreme Programming, Scrum) which were also adopted by the Embedded System community. However, failures and bad experiences in applying Agile Methodologies to the development of embedded systems have not been reported in the literature. Therefore, this paper contributes a detailed account of our first-time experiences adopting an agile approach in the prototype development of a wireless environment data acquisition system in an academic environment. We successfully applied a subset of the extreme Programming (XP) methodology to our software development using the Python programming language, an experience that demonstrated its benefits in shaping the design of the software and also increasing productivity. We used an incremental development approach for the hardware components and adopted a “cumulative testing” approach. For the overall development process management, however, we concluded that the Promise/Commitment-Based Project Management (PB-PM/CBPM) was better suited. We discovered that software and hardware components of embedded systems are best developed in parallel or near-parallel. We learned that software components that pass automated tests may not survive in the tests against the hardware. Throughout this rapid prototyping effort, factors like team size and our availability as graduate students were major obstacles to fully apply the XP methodology.

基于AUTBUS总线的机载无线柔性分布式测试系统数据同步采集技术

本研究致力于机载无线柔性分布式测试系统的研制,以解决在飞行试验中测试系统占地空间大、线缆使用量大、走线复杂、测试通道数量多等问题。分布式系统的节点分布在不同的位置,其内部时钟可能因多种因素而出现不同步的情况,从而影响数据采集的精度。通过灵活的时隙资源分配机制实现AUTBUS总线的动态调整,确保系统通信的高效稳定。采用1PPS、TOD及AUTBUS总线对表算法,系统能够有效地实现全网节点设备的时间同步,确保各个节点在相同的时间基准上进行协同操作。测试数据同步采集基于外部触发的模数转换模块,在全网协同事件的时刻实现各节点数据的同步采集。测试结果表明系统的同步数据采集精度最低为822.5 ns,满足飞行试验中机载测试的数据采集需求。

掘进机器人行驶状态嵌入式传感系统研究

针对掘进机器人履带行驶结构作业处于高冲击、碰撞、高湿度和复杂煤岩底质等空间受限环境、受到的外部动载荷通常无法直接测量或测量比较复杂问题,提出了一种可实时监测掘进机器人履带动载荷的嵌入式传感系统无线监测方法。设计了适用于掘进机器人的特种履带行驶结构,搭建基体-夹板-无线采集模块等组成的多层复合封装防护结构,在封闭环境下对嵌入式传感系统进行无线传输特性及行驶状态下的动应力分布研究,并进行传感系统封装集成的测试精度标定试验。将嵌入式传感系统随机替换履带链环中的一块山型减振垫,对掘进机器人行驶状态周期循环的履带载荷历程进行监测测试。结果表明,该嵌入式传感系统在不改变履带链环整体受力的前提下,能实时采集履带行驶结构的动载荷并无线传输给上位机,动载荷时间历程数据完备、稳定可靠,解决了井下极端工况下掘进机器人履带行驶结构动载荷获取难题。

复杂裂纹涡流检测与评估方法研究

钢轨表面及上表面产生的滚动接触疲劳裂纹通常以斜裂纹或多角度复杂裂纹的形态存在,对其检测和评估是个难题。基于此,采用基于无线能量传输的涡流检测方法(WPT-ECT),设计新的探头结构并结合神经网络算法对裂纹进行检测和评估。首先,有别于现有WPT-ECT方法,采用增大激励频率,而非串并联电容的方式,构造谐振电路;其次,根据复杂裂纹的特点,设计由两个八字形激励线圈和两个矩形接收线圈组成的方向性探头结构;最后,充分提取检测信号的特征,并运用径向基神经网络算法对裂纹进行识别。仿真和实验结果表明,所提出的探头结构对任何角度的缺陷均敏感。同时,RBF算法对斜裂纹、T裂纹、Y裂纹和1.2 mm提离下的T裂纹的识别准确率分别为92.00%、95.27%、96.64%和89.50%。

实时监测铣削力的分体式智能刀柄设计与切削测试

实时监测切削过程可提升表面质量和切削效率,为解决台式测力仪价格昂贵、布置装置过程费时费力等问题,提出了一种可同时测量三轴切削力和相应扭矩的分体式智能刀柄设计方法,搭建了实时监测铣削力的无线传输智能刀柄系统,并基于Kistler 9257B测力平台开展动态测试,验证了智能刀柄铣削力数据的准确性。

压电力传感器信号处理与采集系统设计

为解决旋转式压电测力仪电荷信号的处理和传输难题,设计了一套基于压电力传感器的信号处理与采集系统。设计基于ADA4530-1的信号调理电路实现传感器输出电荷信号的转换放大,基于STM32实现模数转换,采用蓝牙模块实现信号的无线传输,搭建基于LabVIEW的上位机软件进行力信号的采集。利用标准压电传感器对信号处理与采集系统进行实验测试,结果表明:信号调理电路模块的测量误差在0.2%以下,无线传输功能正常,上位机软件能够实时采集力信号数据,相对误差在0.5%以下,能够满足使用需求。

面向高速磨削强化传热的振荡热管测试平台设计研究

振荡热管砂轮在航空难加工材料的磨削加工中可以显著降低磨削温度,防止磨削烧伤。为了更好地指导振荡热管砂轮设计,需探究振荡热管在不同旋转条件下的传热性能,文中设计了全新的旋转振荡热管传热性能试验平台。通过磁耦合谐振无线供电的方式为振荡热管的加热元件供电,实现振荡热管模拟磨削热载荷的加载;通过微控制器采集温度信息,并以无线通信的方式传输温度数据,以克服现有的基于电刷滑环的试验装置在高转速下存在的信号干扰和机械磨损等问题;通过试验确定了无线供电装置的最佳工作参数,测定了信号采集系统的测量误差,并通过旋转振荡热管的传热性能试验验证了测试平台的性能。

无线应变采集技术在飞机强度试验的应用研究

为解决应变测量过程中线缆过长、体量过大、工序复杂造成的测量准备周期长、工作量大、故障定位困难、试验空间紧张等问题,研制了基于超薄芯片封装技术的无线采集系统。该系统体积小、线缆少、就近采集、机体共形、安装方便,在MA600全机疲劳试验中进行了应用验证,取得了良好的效果,表明该系统能够满足试验的要求。

发动机旋转部件温度实时无线测试系统设计

为了在航空发动机试验时,对旋转部件的温度状态进行实时监测,利用铂(Pt)薄膜热电阻温度传感器和STM32,设计了多通道温度实时无线测试系统。该系统以STM32控制多路选择开关和放大器等元器件,并使用其片内模/数转换器(ADC)对多路电信号进行转换,通过无线技术将温度数据发送到上位机。在涡桨发动机试验台完成了对桨叶的温度实时无线测量,解决了旋转部件无法引出信号线进行实时温度监测问题。实验结果表明,该系统的测量精度优于0.1℃,分辨率达到0.01℃。

田间无线测试系统设计与试验

处于田间工作的农业机械工况复杂,工作条件恶劣,其主要旋转部件转速和负荷是否达到设计值,一直是设计者关心的问题,但由于测试手段的限制,问题一直没有得到很好解决。为此,尝试将新的无线数据传输技术应用到4YW-2型逆向配置背负式双行玉米收获机的田间测试中,从而获得玉米收获机田间作业时玉米秸秆粉碎轴的转速、功率等参数,特别是获得了秸秆粉碎轴在大喂入量时消耗的峰值功率,为玉米收获机动力配置提供了可靠的试验数据。田间试验表明:整个测试系统方便可靠,避免了因布线带来的麻烦,提高了现场测试的安全性。

一种简约化GSM-R网络优化方法及系统的研究与实现

对于非列控区段的普速铁路,由于线路等级不高,通常没有配套建设GSM-R无线信号监测设备,也无法直接照搬高速铁路的网络优化及监测系统。为此提出一种简约化的GSM-R网络优化方法和系统解决方案。利用前端感知终端开展线路侧无线信号采集并进行自动化测试,通过公、专融合的网络形式实现路测数据的一键回传;利用后端服务平台建立智能分析系统模型,实现数据的智能融合分析,初步判断并识别铁路沿线无线信号覆盖薄弱区域、GSM-R服务小区异常等情况,自动生成测试报告和网络优化解决方案,并将相关信息传递给线路侧维护人员,以便其及时、精准地进行现场网络优化工作。采用这种智能化、简约化的网络优化方法,符合提质增效、一体化综合维修的建设思路。

基于无线通信的铁路站场动态显示系统设计与实现

铁路站场内外的各类信息数据呈几何级增长,在电务维护、电气调试、联锁试验及应急故障处理中,缺乏有效的电子化、可视化、智能化设备,用以保障试验记录的完整性。提出一种基于无线通信的铁路站场动态显示系统设计方案,重点对系统总体架构、主要功能与实现、应用场景及其优势进行论述。该系统结合铁路电务维护场景与计算机技术,复现站场状态和设备电气特征。通过采集轨道区段占用状态、信号机开放状态、道岔定反位状态、电气状态信息等数据,进行逻辑运算处理后展示在室内显示界面,动态信息数据通过加密及无线通信发送至室外手持终端,同步显示站场信息。该系统有效解决了室外作业无可视化设备的问题,提高了室外作业人员的主动性,为现场调试维护作业提供了辅助技术支持,保障了记录的正确性和完整性,并降低了作业及应急处理时的潜在风险。