• CN:11-2187/TH
  • ISSN:0577-6686

›› 2013, Vol. 49 ›› Issue (4): 13-19.

• 论文 • 上一篇    下一篇

钢丝绳电磁检测信号的时空域理论分析

曹青松;周继惠;李健;刘丹   

  1. 华东交通大学载运工具与装备教育部重点实验室
  • 发布日期:2013-02-20

Theoretical Analysis of Space-time Signals for Electromagnetic Detection of Ropes

CAO Qingsong;ZHOU Jihui;LI Jian;LIU Dan   

  1. Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University
  • Published:2013-02-20

摘要: 钢丝绳电磁检测信号是一种与时间及缺陷位置相关的时空域信号,采用虚拟无限多探头技术,借助Dirac delta函数,建立传感器探头信号的时空域数学模型。通过离散周期信号频谱分析原理讨论时空域信号的频谱特性,利用多采样率原理研究探头运动速度对输出信号频谱的影响。参照时域采样定理,定义及研究空域信号采样定理,空域信号的固有频率与缺陷形式、传感器作用域等特性有关,传感器的运动以其截面中心点为考察点,分别考查多种传感器作用域与缺陷形式下的空域信号固有特性。对时空域信号的时域频率与空域频率进行归一化处理,考查时域频率与空域频率不同关系下的时空域信号采样频率的选择与采样方案的确定,得出统一的时空域信号采样定理。实例分析探头作用域、运动速度、时域信号等对时空域信号采样的影响,进一步验证时空域信号采样定理的正确性。研究成果可推广到相关检测系统等应用场合,所提出的时空域信号采样定理具有一定的普适性。

关键词: 电磁检测, 钢丝绳, 频谱分析, 时空域采样定理, 时空域信号, 虚拟无限多探头技术

Abstract: Electromagnetic detection signal of wire ropes is a kind of space-time signals relating to time and defect position. Virtual infinite multi-probers technology is adopted to deduce the time-space domain mathematical model of the sensor with aid of Dirac delta function. Spectrum characteristics of the space-time signal are discussed by spectrum analysis principle of discrete periodic signals, and the influence of velocity of the prober on the output signal spectrum is studied using multi-sampling rate theorem. Referring to the sampling theorem of time signal, the sampling theorem of space domain signal is defined and researched, and the natural frequency of space domain signal is determined by the form of defect and the effect region of sensor. With its section centre as the reference point during moving process of sensors, the inherent characteristic of space domain signals is investigated under many kinds of sensor region and defect form. The space domain frequency and the time domain frequency of time-space signals are normalized, sampling frequency is chosen and sampling scheme is determined in several different relationships of time frequency and space frequency. Then a unified sampling theorem on space-time signals is obtained. The effect of prober domain, velocity and time signal on the sampling of time-space signals is illustrated and the sampling theorem of space-time signal is validated. Research results can be extended to applications of related detection system and the sampling of time-space domain signal has certain generalization.

Key words: Electromagnetic testing, Sampling theorem of space-time signal, Space-time signal, Spectral analysis, Virtual infinite multi-probers technology, Wire ropes

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