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分析了一种基于布拉格光纤光栅(FBG)的高效方便的谐振频率检测系统。布拉格光纤光栅作为传感器粘贴在悬臂梁表面探测其振动,密集波分复用器(DWDM)作为波长解调器件通过透过率曲线获得布拉格光栅反射光的相对中心波长位移。通过计算机处理数据采集卡采集的实时信号获得悬臂梁多阶谐振频率。结果显示,在与传统的加速度传感器测量谐振频率进行比较时,两者结果很好地吻合。光纤光栅传感系统测得所需的1~4阶悬臂梁谐振频率在频谱上的信噪比均大于20 dB,系统的应力动态测量精度为2.45×10-9ε/Hz,表明该系统能够有效地测量谐振频率。
An efficient and convenient resonant frequency detection system based on Bragg grating (FBG) is analyzed. Bragg fiber gratings are used as sensors to detect the vibration of the cantilever beam. Dense wavelength division multiplexer (DWDM) is used as a wavelength demodulator to obtain the relative center wavelength shift of the reflected light from the Bragg grating through the transmittance curve. The multi-order resonance frequency of cantilever was obtained by real-time signal collected by computer processing data acquisition card. The results show that the results agree well with the traditional accelerometer measured resonant frequency. The signal-to-noise ratio of 1 ~ 4-order cantilever resonances measured by FBG sensing system are more than 20 dB in the spectrum, and the dynamic stress measurement accuracy of the system is 2.45 × 10-9ε / Hz, indicating that the system is effective Measure the resonant frequency.