Study on A Novel of Type CFBG Vibration Sensor

摘要

Vibration monitoring is one of important technology means for large electromechanical equipment's safety-alert and malfunction-diagnosis, and also a hot problem studied for a long time at home and abroad. Vibration sensor is key part for the technology means, but traditional electromagnetic vibration sensors arc restricted for use in the field due to their weak competence to anti-electromagnetic interference. It is inevitable and imminent to develop novel type of vibration sensors instead of them. Aiming at the above-mentioned demand, the authors in the paper fabricate a push-pull type of chirped fiber Bragg grating (CFBG) vibration sensor based on matching demodulation. The authors, at first, set up mechanical model of the sensor, then analyze the principle of CFBG matching demodulation and get the relation between acceleration and output voltage at last. The sensor has such functions as anti-electromagnetic interference, temperature self-compensation and combining vibration sensing and dynamic wavelength demodulation. Moreover, some experiments are done to study its sensing properties and the results indicate that its sensitivity is 369mv/g, linearity degree is over 99.9%, repeatability is superior to 2%, measurement bandwidth is from 10Hz to 400Hz, acceleration measurement range is 8g, and the minimal cross-axis anti-interference is 30dB. To sum up, the sensor is competently used for monitoring the vibration of large electromechanical equipment.