利用差压原理的涡街信号检测方法研究

采用压电传感器的涡街流量计在测量中容易受到管道振动和流场振动的影响,测量精度下降.对漩涡发生体周围流场进行分析,发现在发生体两侧存在相位差为180°且振动幅度和频率相等的流体振动点,根据这一特点,提出采用差压原理检测涡街信号的新方法,这种方法能抵抗噪声,稳定性好,实现方便,适应性强.     

光纤与电子传感器负压波信号对比实验

负压波技术是管道泄漏监测的有效手段。为获取更精确的负压波拐点信息,提高信噪比,采用102.8 m管道实验平台,根据不同环境下传感器监测负压波信号,对光纤传感器与传统电子压力传感器在响应时间、静态稳定性、抗电磁干扰等方面进行了对比实验分析。实验结果表明,在同等的管道工况下,光纤传感器从泄漏负压波信号的获取到压力信号的重新恢复稳定约需30 ms,远优于电子传感器500 ms的响应时间。在静态稳定性实验中,光纤传感器压力信号输出稳定,压力波动范围±0.001 MPa,远小于电子传感器压力输出变化±0.006 MPa。综合评价分析表明,光纤传感器具有良好的稳定性及抗电磁干扰性能,在管道泄漏监测及能源、化工等领域有着广阔的应用前景。     

膜片式光纤动态压力传感器的研制

为了更好地满足动态压力的测量需求,研究了一种基于法布里-珀罗（Fabry-Perot,F-P）干涉原理的膜片式光纤动态压力传感器。从理论上分析了多个反射面对F-P腔光谱的影响,提出了得到单一F-P腔的方法。进而采用机械研磨的方式对传感器膜片外表面进行粗化加工,有效解决了由多个反射面带来的光谱复杂问题。对传感器进行静态压力和动态压力标定试验,结果表明：传感器性能良好,在0~200 kPa（表压）范围内的静态压力测量误差小于等于0.5 %FS;在20~2500 Hz范围内,传感器的幅值灵敏度相对误差优于±10%。     

Distributed strain measurement in a rectangular plate using an array of optical fiber sensors

Single mode optical fiber waveguide has been used to determine the two-dimensional strain distribution on a simply supported rectangular plate. Each of the fifty individual fibers in the rectangular grid array attached to one surface of the plate yields a measurement of the strain integrated along the length of that fiber on the specimen. By using similar sensor information from all of the fibers, both the functional form and the amplitude of the distribution may be determined. Limits on the dynamic range and spatial resolution are indicated. Applications in the measurement of internal strain and the monitoring of physically small critical-structural components are suggested.     

指感压力可控的脉象信号采集装置

通过压力可控的微型气泵和气囊模拟医者诊脉过程的手指指感压力,在不同压力状态下采集脉象信号.微型气泵产生的压力由电磁阀调节,脉象传感器被固定在附有气囊的腕带上,整套装置由DSP芯片控制.脉象信号被采集后,经过滤波放大处理,A/D转换,最终通过串口发送到上位机,实现了不同压力状态下脉象信号的采集和对比.通过对腕带的改进,使脉象传感器的采集压力可控且能连续变化,采集模式更加接近手指诊脉.     

车用压力传感器自动化校准系统的设计

设计了一套基于虚拟仪器(LABVIEW)的车用压力传感器自动化校准系统.该系统采用模糊参数自整定PID控制器和高低温箱,分别实现系统压力和温度的自动化精确控制,上位机通过RS232接口与高低温箱的控制器进行通信.实验结果表明,校准后的传感器的输出误差在0.1%以内,系统精度较高.系统的各项技术参数均能够满足汽车工业中大批量生产压力传感器的情形.     

LFM脉冲信号的联合互相关实时检测算法

针对线性调频(Linear Frequency Modulated,LFM)脉冲信号在水声跟踪系统中的实时检测问题,提出了一种基于互相关的联合检测算法。该算法将接收到的声信号分别与修正后副本及上周期实际声信号样本进行相关,并按照一定加权系数将两次互相关数据进行融合处理,实现LFM脉冲信号的有效检测。经过仿真分析及湖上试验,证明该算法具有较高的检测精度,是水声信号处理的一种实用方法,可有效提高水声跟踪系统的检测性能。     

气体涡轮流量传感器叶轮压力的数值模拟

在严格按照实际涡轮流量传感器几何结构的基础上,运用Solidworks三维建模,通过运用计算流体动力学的方法对内径为80mm的气体涡轮流量传感器进行了数值模拟,给出了流量计在不同流量下内部的压力场并特别给出叶轮表面的压力分布.从压力分布分析叶轮部分的受力情况,以此来讨论叶轮动受力.     

A novel optical pressure sensor based on surface plasmon polariton resonator

We propose a Metal–Insulator–Metal structure consists of two surface plasmon polaritons (SPPs) and an H-shaped resonator. The reflectance spectrum is numerically simulated by the two-dimensional finite-difference time-domain method. The results show that this structure can act as a pressure sensor. To our knowledge, this is the first proposal to utilize the SPP resonator to form a pressure sensor. The size of the SPP resonator can be as small as a few hundred nanometers. The nano-scale pressure sensor opens a wide field for potential applications in biological and biomedical engineering.     

基于足底压力信号的步态识别

设计了一款基于足底压力传感器的足底测力系统,对压力传感器进行选型布局,设计信号调理电路,对采集到的压力信号进行放大及滤波处理,搭建硬件平台,设计信号采集界面;进行传感器标定实验以及足底测力系统实验,采集测试对象以不同步速进行平地行走以及楼梯行走时的足底压力信号;对采集到的足底压力信号进行比例运算,确定模糊集,设计隶属函数,以比例信号作为输入量进行模糊化处理,采用Larsen产品暗示法作为推理算子建立模糊规则推理,根据模糊输出信号识别出步态相位。     

光谱吸收式光纤甲烷气体传感器及其信号处理方法

基于气体在其特征吸收波长下光的吸收随浓度变化的机理,通过对甲烷气体吸收光谱的分析,提出了一种光谱吸收式全光纤甲烷气体传感器及其系统。该系统以1300nm波段的DFBLD作为光源,波长响应范围为1100~1900nm的高灵敏度、低噪声的InGaAsPIN作为光电探测器,利用锁相放大器对传输信号进行相敏检波,采用一次谐波反馈光源注入电流、二次谐波与一次谐波的比值作为系统输出的谐波检测技术对微弱信号进行处理,使得系统达到很高的灵敏度。研究表明,该传感器的灵敏度达到10ppm,精确度和稳定性等性能指标均可满足甲烷气体检测要求。     

Characterization and simulation of optical sensors

Numerical simulation is gradually becoming an advantage in active safety. This is why the development of realistic numerical models enabling to substitute real truth by simulated truth is primordial. In order to provide an accurate and cost effective solution to simulate real optical sensor behavior, the software Pro-SiVIC™ has been developed. Simulations with the software Pro-SiVIC™ can replace real tests with optical sensors and hence allow substantial cost and time savings during the development of solutions for driver assistance systems. An optical platform has been developed by IFSTTAR (French Institute of Science and Technology for Transport, Development and Networks) to characterize and validate any existing camera, in order to measure their characteristics as distortion, vignetting, focal length, etc. By comparing real and simulated sensors with this platform, this paper demonstrates that Pro-SiVIC™ accurately reproduces real sensors’ behavior.     

交流电力智能传感器粗信号处理实验平台的软件设计

在Keil集成开发环境中设计采用单片机的交流电力智能传感器实验平台的软件系统。该软件包括信号采集、信号预处理、粗信号处理等功能模块,分别完成电力信号的采样与保存,交流电力周期与偏移量的获取,基于定义法、相关分析法、最小二乘法的交流电力难测特征参数幅值与初相位的分析。实验表明,该软件能较好地实现交流电力智能传感器的多种粗信号处理方法,满足实验平台的要求。     

压电式压力传感器动态特性补偿技术研究

针对近爆区冲击波压力测试中压电式压力传感器因动态特性不佳造成信号畸变之问题,通过激波管动态校准试验,分析传感器动态特性;对造成动态测试误差的主要因素,利用动态补偿技术设计数字补偿滤波器,对传感器爆炸信号进行补偿处理。结果表明,该方法能有效减小动态测试误差、提高近爆区冲击波压力测试精度。     

雷达调频编码脉冲信号的设计与处理

现代雷达为获得较高的距离分辨力通常采用编码频率脉冲串信号和步进频率脉冲串信号,但都存在数据率低和较为严重的距离-多普勒耦合问题。在研究这两种信号特点的基础上,提出了调频编码脉冲信号形式并给出了相应的信号处理方法。经仿真对比可见,该信号形式及其处理方法能同时解决步进调频信号高距离-多普勒耦合、低数据率两大问题,具有较好的联合分辨力。     

电容式薄膜真空压力传感器设计

电容薄膜真空计广泛应用于中、低真空的测量,为了提高电容薄膜真空计的测量准确性,将算法应用于电容式薄膜压力计的数据处理中。分段拟合方法可以根据每个数据段上的数据特性,使每个数据段上的误差数据曲线拟合得更加准确。然而,这种方法会在边界点处出现数据点跳跃间断的问题,这对实际使用有很大影响。文章设计了一种基于模糊控制原理的数据处理算法,以消除气压测量值在分界点处的跳跃间断问题。经过模糊控制算法的处理,电容薄膜真空计的测量精度得到了提高,气压测量数据曲线在全范围内具有良好的连续性。

     

CW脉冲回波信号的最小方差无畸变响应自适应检测

建立了适用于解析时间序列信号检测的最小方差无畸变响应(Minimum Variance Distortionless Response,MVDR)自适应处理模型(Time Series MVDR,TSMVDR),并针对CW声纳脉冲回波信号,通过构造解析信号和分段近似处理给出了相应算法(Algorithms of TSMVDR on CW pulse signal,AWMVDR),并进行了数值仿真研究。研究结果表明:对于CW脉冲信号:(1)在较高采样率的条件下,AWMVDR可以实现CW脉冲信号稳定的自适应检测;(2)AWMVDR较常规线性相关检测具有更高的脉冲参数估计精度和时间分辨力;(3)AWMVDR的实现需要付出较高采样率和更大计算量的代价。     

模基水声信号处理技术的研究现状和展望

常规信号处理方法的前提条件相对简单,不能满足水声信号处理中海洋环境非平稳和极低信噪比等实际情况。基于模型的信号处理方法(模基处理技术)能够将物理模型引入到信号处理算法中,并且能够有效利用先验信息提高信号处理的性能,是一种有潜力的信号处理技术。结合多年的模基水声信号处理研究基础,首先介绍了模基处理的基本概念,然后介绍了模基处理器的基本框架和其主要优势,进而对模基技术在水声信号处理各个应用领域的研究现状做了全面的归纳和简要的评述,在此基础上,分析了该领域进一步的研究方向。     

Optical fibre-based sensors for distributed strain monitoring of asphalt pavements

Strain distribution of asphalt pavement varies in transverse and longitudinal directions, and distresses, such as cracks, ruts and settlements, often occur randomly, which can be efficiently measured by distributed optical fibre sensing technology. As bare optical fibre is weak to resist shear and torsion forces during pavement construction, the protective technique is required. Therefore, a flexible asphalt-mastic packaged optical fibre sensor was developed in this research for distributed strain monitoring of asphalt pavement. Theoretical analysis on strain transfer of the optical fibre-based sensors embedded in asphalt pavement was conducted to improve the design of the protective layer and remove the strain transfer error. Afterwards, laboratory tests on the asphalt concrete beam were carried out to validate the performance of the sensor. Finally, the proposed sensors were applied to detect the in situ performance of urban asphalt pavement under temperature and traffic loads. The results indicate that the proposed optical fibre sensor detects the distributed strain of asphalt pavement effectively, and the in situ data show significant effects of temperature and traffic loads on asphalt concrete course. This research contributes to the full-scale monitoring and health assessment of large-span pavement.     

Surface roughness and the sensitivity of D-shaped optical fibre sensors

In this paper, the surface roughness characteristic of D-shaped optical fibre sensors with its effects on the sensitivity has been studied. The ULTRAPOL end and edge polishing system was used with some modifications to fabricate the D-shaped sensors with planar sensing zone from the single-mode optical fibres. The mean surface roughness of 343, 96, 25 and 9?nm was estimated at the sensing zone of the D-shaped sensors which were sequentially polished with 30, 9, 3 and 0.5?µm grit size polishing films, respectively. From the experimental results, it has been observed that surface roughness of the sensing zone does not exhibit the significant effects on the output signal strength, whereas the sensitivity of the D-shaped sensors nonlinearly related with the surface roughness of the sensing zone. The designed D-shaped optical fibre sensors have potential applications in biomedical and chemical industries.