滑动式光纤布拉格光栅位移传感器

Sliding type fiber Bragg grating displacement sensor

为克服现有光纤光栅位移传感器设计中存在的传力介质弹性系数易改变、滑块易产生偏移等对测量精度的不利影响,提出了一种滑动式位移传感器。楔形滑块的滑动面和限制面的采样互相垂直、等强度梁的变截面和一体化、滑动面圆弧化等特殊设计,使传感器具有抗滑动干扰性、梁挠位移测量的高灵敏性、长期往复测量的耐磨性等优点。阐述了传感器测量原理,加工制造了传感器原型,并开展了全面的性能测试。测试结果和误差分析表明:传感器在0~100mm的量程中,灵敏度为20.11pm/mm,精度达到0.099 5%F.S,具备良好的微位移测量能力;重复性误差和迟滞误差分别仅为0.705%和0.403%,且抗蠕变性能良好,可满足机械装备、土木工程等重大设施的结构健康监测对位移、变形测量的精度和长期稳定性要求。

In order to overcome the negative influence of elasticity coefficient changeability of forcetransmitting medium and directional movement of sliding block on the measurement accuracy of existing fiber Bragg grating （FBG） displacement sensors,a novel sliding type FBG displacement sensor was investigated.Special design and measures were adopted,including perpendicular sliding surface to the constrain face of sliding block,constant-strength beam with altered cross-section,and circular sliding surface of the beam,which enable the sensor to possess anti-interference of directional sliding,high sensitive measurement to beam deflection,and abrasion performance in reciprocating displacement measurement in long-term.The measuring principle of the sensor was deduced and a sensor prototype was manufactured for performance testing.Experimental results demonstrate that displacement sensitivity of the sensor is 20.11 pm/mm in the range of 0-100 mm,and the measuring accuracy is 0.999 5％ F.S,which indicate that the sensor is a promising candidate for micro displacement measurement.Moreover the repeatability error and hysteresis error are only 0.705 ％ and 0.403％ respectively,which demonstrates good creep resistance of the sensor.These excellent performances can satisfy the requirements of high precision and long term stability in structural health monitoring of machinery equipment and civil engineering.