Fiber optic displacement sensor used in railway turnout contact monitoring system

Railway turnout contact monitoring is very important in high-speed rail operation systems. In order to measure the distance between the sharp rail and the basic rail in a switch system, a wide-range, high-precision fiber Bragg grating (FBG) displacement sensor was designed. Because the distance between the sharp and basic rails is always greater than 14 cm, the measurement range width and accuracy of the proposed sensor system are ensured through the use of a long spring and a beam of constant strength. A differential compensation method is used to eliminate temperature effects. Test results show that the resolution of the proposed sensor is 0.040 mm and the measuring range is 0—170 mm. A field test was also carried out to evaluate the performance of the sensors.     

用于颅内压监测的微型光纤法珀压力传感器

研究了一种用于颅内压测量的膜片式光纤法布里-珀罗压力传感器.外玻璃管和用于光纤准直的内玻璃管采用UV胶粘接,构成空气腔.在空气腔的一端粘接石英膜片,另一端插入多模光纤,石英膜片和光纤端面的两个反射面构成法珀干涉腔.制作了两种不同尺寸的传感器,在0～25 kPa的压力测量范围内,灵敏度高达39.2 nm/kPa,压强测量分辨率为133 Pa,线性拟合度为99.9％,具备生物兼容性,满足人体颅内压测量的需求.与商用的颅内压测量传感器相比,该传感器制作方法简单、成本低廉.