为了对液压管路中的故障进行程度和类型的识别与定位, 提出多元变分模态分解(MVMD)和瞬时相位特征与主频幅值加权融合的方法, 采用分布式光纤布喇格光栅(FBG)监测管路应变, 从传感器信号的相位和幅值中提取有效故障特征, 并进行了仿真实验。仿真结果表明: 根据加权融合特征向量可以有效地对管路故障特征进行识别和定位, 故障程度识别正确率达98％以上。

A novel distributed weak fiber Bragg gratings (FBGs) vibration sensing system has been designed to overcome the disadvantages of the conventional methods for optical fiber sensing networking, which are: low signal intensity in the usually adopted time-division multiplexing (TDM) technology, insufficient quantity of multiplexed FBGs in the wavelength-division multiplexing (WDM) technology, and that the mixed WDM/TDM technology measures only the physical parameters of the FBG locations but cannot perform distributed measurement over the whole optical fiber. This novel system determines vibration events in the optical fiber line according to the intensity variation of the interference signals between the adjacent weak FBG reflected signals and locates the vibration points accurately using the TDM technology. It has been proven by tests that this system performs vibration signal detection and demodulation in a way more convenient than the conventional methods for the optical fiber sensing system. It also measures over the whole optical fiber, therefore, distributed measurement is fulfilled, and the system locating accuracy is up to 20m, capable of detecting any signals of whose drive signals lower limit voltage is 0.2 V while the frequency range is 3Hz . 1000Hz. The system has the great practical significance and application value for perimeter surveillance systems.