共查询到20条相似文献,搜索用时 15 毫秒
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Digital time-of-flight measurement for ultrasonic sensors 总被引:15,自引:0,他引:15
Marioli D. Narduzzi C. Offelli C. Petri D. Sardini E. Taroni A. 《IEEE transactions on instrumentation and measurement》1992,41(1):93-97
Ultrasonic sensor measurements are mostly based on the determination of the time of flight (TOF). The development of a digital algorithm for pulse-echo measurement applications, based on the use of a cross-correlation function to determine the TOF, is presented. Some experimental results are presented, and the possibility to realize a low-cost real-time measurement system is considered 相似文献
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Angrisani L. Baccigalupi A. Schiano Lo Moriello R. 《IEEE transactions on instrumentation and measurement》2006,55(4):1077-1084
This paper deals with distance or level measurements based on ultrasonic time-of-fight estimation. Moving from a past experience concerning the proposal of a method based on discrete extended Kalman filter (DEKF) to overcome some limitations of already available ultrasonic-based techniques, a new digital signal processing method capable of granting further improvements is presented. The method is based on the unscented Kalman filter (UKF), which is a new extension of the Kalman filter theory mandated to face some DEKF problems, mainly due to its inherent linearization approach. To this aim, UKF is applied to the acquired ultrasonic signal in order to estimate the returned echo envelope as well as to locate its onset more accurately. After describing key features and implementation issues of the new method, the results obtained in a number of tests on simulated and actual ultrasonic signals, which assess its reliability and effectiveness as well as advantages with respect to the previous one, are given. 相似文献
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《中国测试》2019,(10):34-39
针对应用超声脉冲回波法测量三层结构中的硅橡胶薄层厚度时回波混叠的问题,提出一种基于RLS(recursive least square)自适应滤波的解决方法。该方法将硅橡胶层下界面回波发生混叠的信号作为输入信号,将无硅橡层时的回波信号作为期望信号,通过RLS自适应滤波算法的处理提取出相互分离的有效下界面回波信号,实现硅橡胶薄层的测厚。研究不同滤波器阶数和遗忘因子对信号分离及测厚精度的影响,以输出信号的信噪比为指标选择最优的滤波参数。结果表明:该方法能够有效分离出发生混叠的硅橡胶薄层界下界面回波,能够测量0.15,0.17,0.19,0.21 mm 4种厚度的硅橡胶薄层,对回波部分混叠和完全混叠两种情况均有良好的适用性。 相似文献
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One of the challenging tasks in the field of ultrasonic NDE is to obtain quantitative flaw size, shape, and orientation information. In an equivalent flaw sizing approach, flaws in a material are reconstructed in terms of a best-fit simple shape such as an ellipsoid or ellipse. In this work, a new time-of-flight equivalent (TOFE) flaw sizing method is developed for obtaining best-fit equivalent flaws from a relatively small number of timing measurements at different transducer orientations. The performance of the method is demonstrated on synthetic numerical data and with experiments, including examples of sizing in anisotropic composite materials and in welds. 相似文献
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应用超声技术的燃烧气体温度测量方法的研究 总被引:1,自引:0,他引:1
高温气体瞬时温度的测量一直是温度测量中的难点,主要原因是温度高,压强大,温度变化速度快。传统的温度测量方法,无法实现温度的快速准确测量。在理想气体中,超声波的传播速度与气体绝对温度的平方根成正比,利用超声波频率差的测量测得气体介质的温度。基于此,本文提出了一种超声温度测量方法并实现了测量系统,同时解决了系统探头的安装、高速计数和数据的二次脉冲锁存问题。 相似文献
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A method based on random-fuzzy variables for online estimation of the measurement uncertainty of DSP-based instruments 总被引:1,自引:0,他引:1
Ferrero A. Gamba R. Salicone S. 《IEEE transactions on instrumentation and measurement》2004,53(5):1362-1369
The evaluation of the uncertainty of the result of a measurement performed by a DSP-based instrument is usually a complex and difficult task. The sources of uncertainty are the instrument input stage and the analog-to-digital converter (ADC), so that each input sample to the instrument can be considered a measurement result with its associated uncertainty. The uncertainty on the final measurement result is obtained as the combination of the uncertainty values of each sample, according to the measurement algorithm implemented on the digital signal processing (DSP) system. This paper proposes an innovative approach, based on the representation of the measurement result and its associated uncertainty in terms of random-fuzzy variables, that, after having suitably characterized the metrological performance of the input stage and analog-to-digital converter, provides an online estimation of the measurement uncertainty. The method has been validated experimentally, and the results of the experimental work are reported. 相似文献
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针对非线性非高斯系统的剩余寿命(RUL)预测问题,本文提出了一种基于粒子滤波(PF)理论的设备剩余寿命预测方法。首先建立设备的非线性状态空间模型(含有未知的时变参数),然后通过粒子滤波算法估计出设备状态的概率密度函数(PDF),从而根据该PDF计算出设备的RUL。此外,计算设备RUL的期望值和95%置信区间,并对模型的预测效果进行评估,验证预测的有效性和准确性。最后通过齿轮箱的全寿命实验,对本文所提方法的有效性进行实例验证,将实验结果和传统的比例风险模型(PHM)预测结果对比分析,结果表明本文提出的剩余寿命预测方法要优于传统的PHM预测方法。 相似文献
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Shen-Shu Xiong Zhao-Ying Zhou 《IEEE transactions on instrumentation and measurement》2003,52(3):742-747
In this paper, adaptive filtering approaches of colored noise based on the Kalman filter structure using neural networks are proposed, which need not extend the dimensions of the filter. The colored measurement noise is first modeled from a Gaussian white noise through a shaping filter. The Kalman filtering model of colored noise is then built by adopting an equivalent observation equation, which can avoid the dimension extension and complicated computations. An observation correlation-based algorithm is suggested to estimate the variance of the measurement noise by use of a single layer neural network. The Kalman gain can be obtained when a perfect knowledge of the plant model and noise variances is given. However, in some cases, the difficulties of the correlative method and the Kalman filter equations are the amount of computations and memory requirements. A neural estimator based on the Kalman filter structure is also analyzed as an alternative in this paper. The Kalman gain is replaced by a feedforward neural network whose weight adjustment permits minimization of the estimation error. The estimator has the capability of estimating the states of the plant in a stochastic environment without knowledge of noise statistics. If the noise of the plant is white and Gaussian and its statistics are well known, the neural estimator and the Kalman filter produce equally good results. The neural filtering approaches of colored noise based on the Kalman filter structure are applied to restore the cephalometric images of stomatology. Several experimental results demonstrate the feasibility and good performances of the approaches. 相似文献
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《中国计量学院学报》2017,(4):460-466
车道线检测是智能驾驶系统的重要组成部分,它提供了车辆与车道位置关系的信息.针对智能车辆驾驶系统在视觉导航过程中车道线检测的精确性和鲁棒性的问题,提出一种有效的车道线检测方法.首先对原始RGB图像分别进行感兴趣区域设定、逆透视变换、灰度化和阈值处理;然后进行霍夫变换处理,利用斜率和中心点位置筛选检测结果;最后利用卡尔曼滤波对检测到的线段进行跟踪,预测当前车道线位置.实验结果表明,该算法能够有效解决图像中车道线不清晰以及一些干扰遮挡的问题,车道线检测准确率可达94%,具有较好的准确性、鲁棒性和较低的计算复杂度,有利于实时性检测系统的构建. 相似文献
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Gueuning F.E. Varlan M. Eugne C.E. Dupuis P. 《IEEE transactions on instrumentation and measurement》1997,46(6):1236-1240
This paper presents an efficient algorithm for distance measurement, combining both the pulse time-of-flight method and the CW phase-shift method, It copes with a low-rate sampling technique allowed by the limited bandwidth of two ultrasonic transducers working in air at 30 kHz and with modest software resources of autonomous devices. The measuring system was implemented and tested on a compact Motorola MC68HC16-based platform, with a minimum of attached hardware. Experimental results show an accuracy better than 1 mm for a poor reflecting target at a distance of about 1 m 相似文献
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In today's global market, a critical issue for companies to survive the increasing competition is how to handle uncertainty in their supply network. In this paper, we explore the application of Kalman filtering to estimate the dynamic states in a supply network. Two state-space models are developed. The first one focuses on processing each individual order which includes both waiting time and value-added processing time. Considering the correlation of consecutive orders, the second one enhances the state-space model by employing autoregressive model of waiting time. To signal potential abnormal events, the estimates from the models are further used in control charts with control limits being updated at each monitoring stage according to the related estimation error. A supply network case example is studied and we conclude in the benchmark model (without using Kalman filtering) and the first state-space model, the data collected from the bottleneck stage turns out to be most valuable for increased accuracy in detecting tardy orders. The second state-space model consistently outperforms both the benchmark model and the first state-space model for robustly early detection of abnormalities at all stages, especially the stages before the bottleneck stage, of the system. 相似文献