基于超声波和云测试的油井液面测试系统研究

针对目前油井液面深度测试系统测量范围小、误差大、稳定性低的缺点,提出了基于声波法测动液面原理,利用时间序列分析技术、新息自适应卡尔曼滤波技术来实时检测回波信号,进而实现对油井液面深度的高精度测量和噪声处理;选用FPGA和云测试技术成功实现了油井液面深度测量系统的远程化和网络化;基于云测试的油井液面远程监测系统目前已在油田生产现场通过测试,测试结果表明,系统稳定,算法实时、高效,动液面深度测量误差小,测量精度高,能满足实际工程应用.     

抽油机井工况在线优化节能控制技术研究与应用

目前油田在用的获取抽油机井的动液面主要使用声波测量法或者井下下压力计法,前者存在数据滞后不能实时指导生产的缺点,后者成本高、安装和维护繁琐,限制了规模推广.本文提出一种软件算法来获取动液面,再通过调速机构对抽油机进行在线优化节能控制新技术,该技术为解决动液面数据实时录取和油井运行优化提供了一套切实的解决方案,经试验应用达到了预期目标,具有良好的应用前景.     

基于分形模糊控制滤波处理油井液面深度信号的方法

本文介绍了油井液面探度测量的基本原理,着重论述了利用分形模糊控制滤波处理液面信号的基本方法,最后给出对实验测量信号的处理结果．     

油井综合测试仪的原理及研制

介绍了油井综合测试的基本工作原理和系统组合,还就系统中所涉及的位移传感器,压力传感器,声波传感器等的测量原理作了简要介绍,简述了硬件设计的主要特点,给出了主要扶持指标和实验结果。     

超声波测距回波信号处理方法的研究

在分析超声波测距系统回波信号处理存在问题的基础上,提出了两种提高测量精度的回波信号处理方法.采用了时间增益补偿技术和峰值时间检测技术,可正确检测超声波回波的到达时间.经反复试验,在50 cm～5 m的测量范围内,测距精度可达到0.5%,且测量重复性较好.两种方法的采用,提高了超声波测距系统的测量精度.     

中段目标宽带雷达回波仿真及分析

优化雷达自动识别中段目标,对中段目标宽带雷达回波信号进行建模,为研究中段目标散射特性,实现雷达自动识别中段目标的重要基础,提出建立了微进动目标数学描述方程,采用一种移动散射点模型的散射中心位置计算方法,根据几何绕射理论计算了各散射中心的散射强度,得到了宽带雷达中段目标的回波模型,并针对两种典型目标运用该模型进行回波仿真,获得给定目标在特定战情下的回波仿真信号.仿真结果较好地反映出目标特征,为进一步进行中段目标的识别提供了理论分析依据.     

声波传输测试技术在油田的应用

介绍了油田采油井井下向地面传输测试信号的相关技术,通过声波无线传输测试仪器,解决无法进行常规测试的井下资料录取问题.随着对声波传输技术的深入研究,将在油田生产测试系统中具有广阔的应用前景.     

基于单片机的抽油井液面自动监测仪设计与应用

介绍了一种基于单片机的新型抽油井液面自动监测仪的设计原理和实际应用。该仪器能够从井口自动监测抽油井内环空液面深度变化,通过分析计算获得井下压力的恢复情况,食品以80C552单片机为核心,可靠性高,测量数据准确,在长达一周的监测期间中途不需人工干预,仪器配有大容量非易失性数据存储器,测量数据长期保存不会丢失,并可与上位机通信以便于进行数据分析。     

基于Chirp-Z变换的LFMCW系统测距算法仿真研究

首先介绍了用Chirp-Z变换提高液位测量精度的算法原理,然后仿真出了线性调频连续波雷达(LFMCW)在快速傅里叶变换(FFT)、线性调频Z变换(CZT)在理想回波条件下的测距精度;同时分析并比较了两种测距方法对测距精度造成的影响。理论计算和数字仿真结果表明,此算法可显著提高计算效率和液面雷达的测距精度。     

基于电场成像的液位测量系统的设计与实现

提出一种依据电场成像理论,利用多感应元的液面测量方法。通过运用A／D数据再处理,波动液面模糊控制和感应元学习等手段,有效地消除了传统液位测量方法的一些弊端,提高了液面测量的精度。实验表明,该方法能够精确的测量出多种导电液体的液位,有广阔的应用领域。所设计实验测量系统分辨力可达到4mm,测量误差不大于8mm。     

声速误差对平面波成像质量的影响

在医学超声成像系统中,大多都采用假定声速进行成像.假定声速和真实声速的误差会造成超声图像的空间相位偏移和散焦,降低图像质量.定量分析了声速误差对平面波成像质量的影响.通过Matlab里的k-wave仿真工具箱,获取仿真数据,假定不同声速,通过延迟累加波束形成技术来获得二维超声图像.通过对比度(Contrast Ratio,CR)、对比噪声比(Contrast-to-Noise Ratio,CNR)和点扩散函数(Point Spread Function,PSF)来评价平面波成像质量.在均一介质中,假定了21组不同的声速,其误差范围为±100 m/s;在复杂介质中,选择6种不同的乳腺模型,假定声速为1540 m/s,通过CR、CNR、PSF分别定量分析成像质量.在均一介质中,随着声速误差的增大,成像质量变差.在复杂介质中,成像质量比均一介质中使用正确声速的成像质量差.     

超声波多次回波反射法测量乙醇溶液密度研究

通过测量超声波在不锈钢壁内多次反射回波信号来确定乙醇溶液的声阻抗值,测量从反射板壁面反射回来的二次回波时差来确定溶液中的声速.测得的回波信号经快速傅里叶变换(FFT)处理,得到某一特定频率下的振幅值,将这一系列振幅值在对数坐标下作数据拟合,由拟合斜率值并结合多次反射理论求得溶液的密度.运用该方法对不同浓度的乙醇溶液进行...     

A model-based sound localization system and its application to robot navigation

This paper describes a mobile robot equipped with a real time sound localization system as well as a sonar system for obstacle detection. The sound localization method is based on a model of the precedence effect of the human auditory system to cope with echoes and reverberations. Sound localization and robot navigation experiments were conducted. The results show that the robot is capable of localizing sounding objects in a reverberant environment and approaching the objects without collisions, even when the objects were behind obstacles. Environment flexibility and error robustness of the system were discussed as well.     

Airborne radio echo sounding of outlet glaciers in Greenland

We used a coherent radar depth sounder operating at 150MHz to collect ice thickness data on outlet glaciers in northwestern Greenland. The radar data were collected in conjunction with laser surface elevation measurements and were tagged with GPS information for accurate geolocation. The radar signals were corrupted by multiple echoes between the aircraft and the ice surface, as well as between the ice surface and the ice-bedrock interface. We applied the homomorphic deconvolution technique to remove multiple echoes successfully and have identified the grounding line of a long ice shelf in northwestern Greenland.     

基于声波信号的水平井钻采控制技术

水平井是一种特殊的油井,特点是井眼轨迹多样、井内流体流动状态多变,采用常规钻采控制技术无法有效进行水平井钻采作业.基于声波信号的控制技术对水平井井下环境和介质没有特殊要求,能够实现地面与井下之间的无线信号传输及控制,建立起人井对话平台,长期实时监测水平井钻采动态数据,及时调整钻井的分段和换层,实现了水平井钻采控制自动化和智能化.     

基于梯度差的声速剖面自适应分层算法

声速剖面表示声速与深度的函数关系,常用于水声定位,以纵轴表示海深,横轴表示声速。针对高精度水声定位系统中定位精度与计算量相互矛盾的问题,提出一种声速剖面自适应分层算法。该算法根据声速在有限范围内规律变化的特点,对声速剖面逐层搜索。通过声速层之间声速变化梯度差情况找出声速变化的节点,保留原始声速剖面特征,实现对声速剖面的简化。仿真实验结果表明,根据阈值选取的大小,算法自适应分层处理后对原声速剖面的精简可达70%。在选取合适阈值时,与D-P算法相比可以获得更小的定位误差,具有良好的工程应用价值。     

Differentiating walls from corners using the amplitude of ultrasonic echoes

This paper analyzes the use of ultrasonic echo amplitudes to evaluate the characteristics of the detected surfaces (such as distinguishing between walls and corners). The shape and surface characteristics of the environment, such as roughness or absorption coefficient, as well as the distance and the angle of incidence, have high influence on the amplitude of the echoes. As a consequence, the amplitude of the received echoes has received little attention from robotic researchers. Instead, time-of-flight (ToF) has been used as the main source of information of the environment. It is also well known that the shape of the echoes of a corner is the same as that of a wall [IEEE Trans. Pattern Anal. Mach. Intell. (PAMI), 12 (1990) 560]. Several authors have proposed special multi-transducer configurations to avoid this problem. This paper studies the amplitude of received echoes and presents a simple model to predict the shape and amplitude of echoes received from different materials in environments composed of walls and corners. Using this model, and analysing the amplitude of the echoes it is possible to distinguish between walls and corners in a single scan of a single ultrasonic transducer pair. The parameters of the model were obtained from tests performed on different materials and surfaces. The last section of the paper shows the experimental results of the wall–corner classifications obtained in real tests during the walk of a mobile robot. The results suggest that the method proposed can be of great interest for map building in robotics.     

Building ears for robots: Sound localization and separation

This paper describes our research on bio-mimetic robot audition. Among the many binaural and monaural sound localization cues in the human auditory system, the interaural time difference cue is selected as it can easily be obtained by omnidirectional microphones. We have used a three-microphone system to remove the anterior-posterior ambiguity which occurs in two-microphone (or ear) systems. The echo-avoidance model of the precedence effect is used to cope with the echoes and reverberations of real environments. We mimicked the cocktail party effect by perceptual grouping of continuous components according to the spatial information obtained by the sound localization method. A wheel-based mobile robot equipped with an auditory system was developed. The auditory system has two sound processing parts. One is a DSP-based realtime system; the other is an off-line system composed of remote computers. Experiments of localizing and separating multiple sound sources and robot navigation were conducted to demonstrate the system's ability and potential applications.     

回波混叠对相关测时法超声流量测量的影响

传播时间法超声流量测量中使用相关时延估计需注意回波混叠效应。在矩形窗猝发脉冲激励下,进行了流速范围从3.0m/s到18.9m/s的管道实流实验和距离范围从50mm到200mm的静态测距实验,研究回波混叠对测量的影响。前者传感器距离固定,通过调节激励长度改变回波混叠程度;后者激励长度固定,通过调节传感器间距改变回波混叠程度。结果表明,时延估计性能随混叠程度增大而降低。理论定性分析进一步说明,混叠效应会产生成对回波,使相关输出形状失真,是导致时延估计精度变差的主因。