为了提高基于压电陶瓷(PZT)驱动的可调谐法布里一珀罗(F-P)型滤波器解调的光纤布拉格光栅(FBG)传感系统的实时数据采集速度和测量精度,提出并行处理技术和交流转直流(AC-DC)修正方法。通过并行处理技术,可调谐F-P滤波器连续采样,PZT磁滞性得到抑制,提高了系统实时数据采集速率和测量精度。针对AC驱动电压与F-P滤波器腔长之间的非线性关系,提出AC-DC修正方法,将AC电压下的FBG波长中心位置拟合为DC电压下的中心位置,减小了FBG中心波长的测量误差。实验表明,系统实时数据采集速率最大可提高1倍,应变测量的随机误差降低95%,动态应变传感的灵敏度优于1με,实测应变量与理论计算结果之间的误差小于4%。
An optimized strain demodulation method based on fiber Fabry-Perot (FFP) tunable filtering driven by a piezoelectric transducer (PZT) is proposed and experimentally demonstrated. Using a parallel operation mode to sample data point from FFP filter continuously,the effect of PZT hysteresis behavior is eliminated, and system tuning frequency is increased. Nonlinearity of AC is also considered, and an AC- I)C correction curve is proposed. Experimental results show that system actual acquisition rate can be improved by 100%, and random error of strain measuring is decreased by 95%. Moreover, the strain sensitivity is less than 1με, and the error between the Practical value demodulated by the system and the theroretical value is below 4 %.