Installation position determination of wind speed sensors on steel pole along a high-speed railway

In order to consider the influence of steel pole on the measurement of wind speed sensors and determinate the installation position of wind speed sensors, the flow field around wind speed sensors was investigated. Based on the three-dimensional steady Reynolds-averaged Navier-Stokes equations and k-ε double equations turbulent model, the field flow around the wind speed sensor and the steel pole along a high-speed railway was simulated on an unstructured grid. The grid-independent validation was conducted and the accuracy of the present numerical simulation method was validated by experiments and simulations carried out by previous researchers. Results show that the steel pole has a significant influence on the measurement results of wind speed sensors. As the distance between two wind speed sensors is varied from 0.3 to 1.0 m, the impact angles are less than ±20°, it is proposed that the distance between two wind speed sensors is 0.8 m at least, and the interval between wind speed sensors and the steel pole is more than 1.0 m with the sensors located on the upstream side.

High Speed Column-Parallel CDS/ADC Circuit with Nonlinearity Compensation for CMOS Image Sensors

A high speed column-parallel CDS/ADC circuit with nonlinearity compensation is proposed in this paper.The correlated double sampling (CDS) and analog-to-digital converter (ADC) functions are integrated in a threephase column-parallel circuit based on two floating gate inverters and switched-capacitor network.The conversion rate of traditional single-slope ADC is speeded up by dividing quantization to coarse step and fine step.A storage capacitor is used to store the result of coarse step and locate the section of ramp signal of fine step,which can reduce the clock step from 2 n to 2 (n/2+1).The floating gate inverters are implemented to reduce the power consumption.Its induced nonlinear offset is cancelled by introducing a compensation module to the input of inverter,which can equalize the coupling path in three phases of the proposed circuit.This circuit is designed and simulated for CMOS image sensor with 640×480 pixel array using Chartered 0.18μm process.Simulation results indicate that the resolution can reach 10-bit and the maximum frame rate can reach 200 frames/s with a main clock of 10MHz.The power consumption of this circuit is less than 36.5μW with a 3.3V power supply.The proposed CDS/ADC circuit is suitable for high resolution and high speed image sensors.

A Study on the Sensor Applications for Position Detection and Guideway Monitoring in High Speed Maglev

The high speed maglev is mainly characterized by propulsion using linear synchronous motor (LSM) and vehicle levitation from the guideway surface. In LSM propulsion control, the position detection sensor is used to detect running vehicle position for synchronized current generation. To maintain the stable levitating condition during vehicle running, the irregularity of guideway surface should be monitored by sensors measuring the displacement and acceleration between vehicle and guideway. In this study, the application methods of these sensors in the high speed maglev are investigated and through the experiments by using the small-scale test bed, the validity of examined methods is confirmed.

Influence of Laboratory Environment on the Verification Results of EL15-1A Type of Wind Speed Sensor

According to the verification regulation of the Wind Direction and Wind Speed Sensor of Automatic Meteorological Station[JJG(meteorological)004-2011],relying on the wind tunnel laboratory of Hebei meteorological measurement station,EL15-1 A type of wind speed sensor in the automatic weather station was verified.The experimental data of sensor verification in different laboratory environments were obtained through data comparison.Using standard wind speed measurement formula,the influence of laboratory temperature,humidity and air pressure on verification results was analyzed quantitatively.The results showed that laboratory temperature had the greatest influence on the verification results of this type of sensor,while the humidity and air pressure had less influence.Therefore,it should be noted that the temperature change in the laboratory should not be too large in the process of verification,so as to improve the accuracy of the verification results.

杯式风速传感器在不同计量方式下的分析研究

针对杯式风速传感器在实验室检定和现场校准中出现的计量结果差异,分析了不同计量方式对杯式风速传感器计量结果的影响。选取一组EL15型风速传感器为试验样本,将风杯组件和机身互换组合后,依次开展启动风速和风速示值的计量性能测试。从传感器结构和计量方法原理方面,对比分析不同计量方式下的试验结果差异及其产生原因。研究结果表明:实验室检定方式是杯式风速传感器更可靠、有效的计量方式。现场校准方式可在一定条件下应用,且仅适用于风速传感器低风速范围内校准及传感器的电路性能测试。

OvBNN authentication based on cooperative signature for wireless sensor networks

The universality of the application of wireless sensor networks( WSN) makes more attention be paid on the security problem. Node authentication is not only the basis of network security,but also the premise of key management and secure routing protocol. Although the signature mechanism based on symmetric encryption is high in energy efficiency,it is vulnerable to be attacked and there is a time delay during authentication. Traditional public key encryption mechanism with improvement in security brings in complex algorithm and costs much time,which is not suitable for WSN. In this paper,a signature authentication mechanism,an optimized variant Bellare Namprempre Neven( OvBNN) is presented to quickly complete the authentication by mutual cooperation between nodes so as to make the nodes use the intermediate calculation results of their neighbor nodes directly.Simulation results show that the proposed mechanism is superior to traditional authentication mechanisms both in energy consumption and authentication time.

Design and Data Analysis of a New Type of Antifreezing Cup-Type Wind Velocity Sensor

In most areas of China, affected by the environment of low temperature and high humidity, the wind speed sensor and wind direction sensor are frozen and cannot output data in autumn, winter or the alternation of winter and spring. In order to solve the freezing situation of the wind sensor, this paper designs a new type of antifreeze wind speed sensor. After meteorology performance testing and field observation tests, the correlation coefficient of the observation data is demonstrated, and the data curve is fitted. The result shows the sensor is stable, and has a good antifreeze effect, the data output is reliable.

基于多传感数据融合的变速运行齿轮异常振动故障诊断

变速运行齿轮异常振动故障诊断性能过差会增加汽车维护成本,缩短齿轮使用寿命。为了及时识别齿轮故障,保证汽车变速器总成具有良好的振动特性,提出基于多传感数据融合的变速运行齿轮异常振动故障诊断方法。通过分析多传感器数据融合技术,掌握变速运行齿轮异常振动故障诊断的理论框架,并以此为基础,参考传感器融合模块、特征级并行多神经网络局部诊断模块和终端分类模块,结合变分模态分解、多通道加权融合和单隐层前馈神经网络训练算法,从信号采集、信号特征提取和信号特征分类3个步骤实现变速运行齿轮异常振动故障诊断。实验结果表明:在齿轮发生轻度磨损时,磨损振动信号的幅值在20~40 mV之间,磨损振动信号的频率在0~4000 Hz区间;中度磨损时,信号的幅值在30~55 mV之间,信号频率在3000~7000 Hz区间;重度磨损时,信号幅值在50~70 mV之间,信号频率在6000~12000 Hz区间,且各阶段诊断结果均与故障程度的实际转折点吻合。由此可知在各样本数量均相同的情况下,提出的故障诊断方法预测值与真实值均相同,故障程度和故障类型的诊断性能均较好。

基于双传感器的枕式包装机速度自动调节系统

包装机速度调节系统存在进入稳态耗时长、稳态误差大和调节精度低的问题,导致产品破损率高,提出基于双传感器的枕式包装机速度自动调节系统。系统硬件采用温度传感器和位置传感器,结合可编程逻辑控制器(Programmable Logic Controller,PLC)转换和调配各个机构的速度,实现包装机速度自动调节;系统软件采用等时间原则,确定包装盒传输到封端位置和温度的时间,从而匹配速度,根据齿轮传动原理确定速度变化量,实现枕式包装机速度自动调节。实验结果表明,设计系统进入稳态的耗时仅为20 s,包装破损率均低于7.5%,该系统减小了超调量、缩短耗时、提高控制精度,降低了不同尺寸产品包装破损率,具有较好的通用性和可靠性。

固体推进剂侵蚀燃烧状态下的动态燃速测试方法研究

为了测量固体推进剂在侵蚀燃烧状态下的动态燃速,设计了侵蚀燃速测试系统。该测试系统以透明窗发动机为主体,包括压力传感器、高速相机和数据采集系统。透明窗发动机用于构建推进剂试样产生侵蚀燃烧的高温高压横向燃气流条件,高速相机用于采集试样表面燃烧退移过程。以某制式丁羟推进剂为测试对象,开展了侵蚀燃烧热试车试验,并结合数值研究,对所构建的侵蚀燃速测试方法及数学模型的准确性进行分析与验证。结果表明:该侵蚀燃烧测试方法具有低成本、高效率等一系列突出优点,能够实现单次试验获得多组数据,适用于多种固体推进剂的侵蚀燃速快速测量。

新能源汽车速度传感器故障检测与控制技术分析

随着现代化社会的快速发展,新能源汽车兴起,传感器作为其关键组成部分之一,在推动汽车电动化和智能化发展方面扮演着至关重要的角色。本文基于新能源汽车驱动系统对速度传感器的检测与控制关键进行简单分析,根据分析结果深入探究该装置设备的故障检测与控制技术,最后开展模拟仿真实例分析,以期控制跟踪速度,提高新能源汽车行驶安全性,为相关工作或人员提供有效参考。

一种基于MIPI D-PHY物理层的高速比较器

基于MIPI D-PHY物理层传输协议,文章设计一种高速低功耗的自偏置比较器电路,并对电路进行理论分析和仿真验证。该高速比较器总体结构由二级运放构成:共栅极和共源极以及工作在线性区的NMOS管组成第1级放大结构;电流源作负载的四管运放组成第2级放大结构。差分信号通过NMOS源极进行输入,提升信号的共模电压接收范围。电路结构中无额外电流源偏置,提高数据传输速率的同时减小了功耗。基于SMIC 0.18μm CMOS工艺设计,采用1.8 V电压供电,仿真结果表明:高速比较器能准确接收低共模电平的差分信号,直流增益为37.4 dB,传输速率达到2.5 Gb/s,功耗达到326μW/(Gb/s),可以接收到差分信号的共模电平范围为30~330 mV。

三杯风速传感器非水平风场测量性能

为解决三杯风速传感器在计量检定条件下与观测场景中环境差异所导致的测量数据误差,致力于研究空气流速计量标准在量值传递过程中的真实性、准确性和一致性,为新一代三杯风速传感器作为计量器具的新产品型式评价提供思路和参考指标,依据杯式测风仪测量方法与自动气象站风速风向传感器检定规程,并在实验中加入了主体由角度编码器构成的自动化转盘系统,设计了三杯风速传感器在非水平风场内测量性能水平实验。通过调整三杯风速传感器在风洞试验段内的倾斜角度,模拟其在自然界非水平风场中的测量状态,同步采集风洞的标准指示风速、三杯风速传感器的实测风速以及其相应的倾斜角度,计算示值误差,利用方差分析、趋势分析、相关性分析和线性回归分析等统计方法,对不同倾斜角度下三杯风速传感器示值误差进行研究,得出了三杯风速传感器在风洞试验段内的示值误差与实测风速和倾斜角度之间的相关关系,提出了三杯风速传感器在非水平风场下的测量性能指标。研究了三杯风速传感器在非水平风场中实测风速与标准风速和倾斜角度的回归关系,提出了三杯风速传感器在计量环境下非水平风场中数据的量值传递修正算法。

基于运行数据的风电场风速传感器运行品质评价方法及应用

风电场风速传感器运行的可靠性和稳定性是机组高效发电和安全运行的关键,精准识别风速传感器的失稳和失准等缺陷模式,客观地描述其运行品质对于风电场提寿增效意义重大。该文对风电场风速传感器运行品质评价展开研究,围绕运行、测量、抗扰动等维度,建立风速传感器运行品质标签架构、量化规则和评价模型,提出基于数据驱动的多维标签应用体系,挖掘风电场风速传感器的扰动敏感度、韧性、性能演化趋势、集群特征,为辨识设备的运行态势提供一套精细化数学建模方法。以某风电场运行数据为研究对象,对所提的运行品质评价体系及应用策略进行阐述,验证所提方法在风电场主动运检和精益化管理方面的工程应用价值。

双雷达与轮轴传感器融合的列车高精度测速方法

为在列车运动过程非线性变化、噪声为非高斯的条件下,实现测速传感器的量测误差校准及融合后的速度高精度估计,提出列车测速系统配置双雷达与轮轴传感器,并根据联邦粒子滤波进行融合的测速方法。以CRH3型列车在两车站间从启动到停止的运行全过程为例,将不同速度估计方法在列车产生空转、打滑、振动以及测速传感器存在动态噪声情况下的测速误差进行分析并验证。仿真结果表明:双雷达与轮轴组合进行校准后粒子滤波相对未校准时在空转和打滑阶段均方根误差可分别降低31.52%、47.35%;对比双雷达分离振动速度校准法和双雷达角度偏差估计校准法,双雷达分离振动速度校准法在列车振动速度占比0~1和雷达安装角误差-1°~1°范围内,相对误差最大可降低39.66%。采用联邦粒子滤波融合后的测速结果较融合前双雷达和轮轴传感器滤波测速的结果MAE分别降低34.71%,14.03%,RMSE分别降低26.51%、10.98%。采用联邦粒子滤波融合的方式较联邦扩展卡尔曼滤波融合测速均方根误差降低26.97%,最大绝对误差可降低16.10%。

无人驾驶汽车纵向速度的磁敏传感器控制方法

在无人驾驶汽车行驶过程中,工况的切换导致纵向速度控制难度较大,为提高行驶的稳定性和安全性,提出了基于磁敏传感器的无人驾驶汽车纵向速度控制方法。对无人驾驶汽车纵向运动的参数计算,为磁敏传感器建立基础环境。利用永磁体为磁敏器件提供偏置磁场,计算点磁源磁场强,获得磁敏传感器空间坐标。在空间坐标内,将汽车转速跟踪控制问题转化为连续系统的传感器状态描述,算出加速度和变化速率约束范围,得到最优控制输入增量;为避免制动与驾驶方式频繁转换,将节气门开度和期望制动器主液压控制量作为执行器控制输入,完成汽车纵向速度控制。实验表明,所提方法能够很好地跟踪期望的纵向速度,可以根据探测信息实时地调节控制参数,纵向车速控制效果更加稳定,保证行驶安全。

高速精量播种机带式高速导种装置导种性能红外监测系统研究

为解决带式高速导种装置导种过程中种带托片与种粒均经过监测点,无法区分脉冲变化特征,导种性能难以监测的问题,研究一种基于红外传感器的带式高速导种装置监测方法并设计了监测系统。利用其导种特性提出了双侧脉冲比较法,设计了带式高速导种装置监测模块硬件电路与软件程序。同时通过对监测系统采样试验结果分析,提出一种基于双侧脉冲值分析与能量掩码平滑算法(Bilateral pulse value analysis and energy masking smoothing algorithm,BPV-EMSA)的带式高速导种装置监测算法。仿真试验表明:该算法减少了原始脉冲的噪声和随机波动,使数据更加平滑稳定并突出了数据主要趋势和模式,同时抑制了瞬态脉冲干扰,提升了数据可解释性和分析准确性。监测系统精度试验结果表明:所设计的带式高速导种装置监测系统在不同作业速度下最高监测精度为97.65%,最低精度为95.99%,系统能够精确采集种粒经过监测点的脉冲变化。监测系统性能评价试验结果表明:播种合格率平均监测差值为2个百分点,播种漏播率平均监测差值为1.45个百分点,播种重播率平均监测差值为0.56个百分点。播种合格率相对差值不大于2.23个百分点,播种漏播率相对差值不大于1.78个百分点,播种重播率相对差值不大于1.00个百分点。该监测方法能够准确监测带式高速导种装置的导种性能。

冬季运动智能柔性人台关键技术开发

为精确获得运动姿态下服装对运动员整体和局部关键部位的减阻效果,基于运动员冬季运动动态姿势的三维人体数据,合理构建人台硬质内壳与柔性皮肤层的结构,并结合空气动力学等方法设计薄膜压电传感器的置入点位,为人台搭建完整的传感系统,开发了一款冬季运动智能柔性人台,并对该柔性人台进行了实际的风洞测试。结果表明,该人台可实现多点压力信号实时同步采集,不仅可得到人体局部关键部位的具体阻力数据,还可模拟测试速滑运动员在运动情况下穿着不同材料或不同结构设计的竞赛服装的减阻效果,测试竞赛服装不同部位的减阻情况。智能人台发挥了柔性传感器在服装减阻结构设计中的应用价值,使服装减阻测试更为简单和精确。

基于等分平均原理的转台转速测量方法研究

针对转台运动过程中的转速高精度测量问题开展研究,将等分平均法(Equal Division Average,EDA)应用到转台转速测量领域。首先分析了转台转速测量过程中的误差源,阐述了安装偏心偏斜引起的谐波误差和计数器法带来的±1计数误差对测量精度的影响;采用多传感器等分平均测速实现谐波误差的原理性抑制,提出改进测速方案来降低±1计数误差对测速精度的影响;搭建转台转速测量实验平台验证多传感器等分平均测速效果,实验结果证明了等分平均对谐波误差的抑制作用;150°/s内的多个转速的实验显示EDA方法角速率测量误差小于0.9×10^(-3),角速率测量稳定性优于0.6×10^(-4)。