基于FBG增敏传感技术与WT-MCMC算法的护栏冲击检测技术

Guardrail impact detection technology based on FBG sensitization sensing technology and WT-MCMC algorithm

为实现事故多发点碰撞事故的主动预警,及时启动应急报警救援系统,提高公路的安全防护水平,搭建了护栏监测试验平台,选用一种增敏型光纤光栅应力传感器对碰撞冲击力进行监测;同时针对监测数据外部噪声干扰现象,结合小波变化(WT)原理,采用sym6小波基进行10层分解对冲击信号进行降噪处理;最后根据应力传播呈现正态分布规律的特点,构建了传感器冲击力响应值与冲击力大小和冲击力位置的二元高斯函数,并采用马尔科夫链-蒙特卡洛(MCMC)算法对目标函数进行采样,反演二元高斯函数参数,得到基于监测数据的传感器冲击力响应值与冲击力大小和位置的分布函数。结果表明:增敏型光纤光栅传感器对冲击力的监测值与施加冲击力之间的误差可控制在5%以内,能够满足工程监测的要求;根据试验施加的冲击力大小和位置反演的二元高斯函数冲击力计算结果与传感器冲击力监测结果之间的误差在2%以内,表明反演的二元高斯函数能够实现护栏冲击力大小监测和精准定位。

In order to realize the active early warning of the collision accidents at the accident-prone points,start the emergency alarm and rescue system in time,and improve the safety protection level of highway,a guardrail monitoring test platform was built,and a sensitized fiber grating stress sensor was selected to monitor the collision stress;at the same time,based on the principle of wavelet change(WT),sym6 wavelet base was used for 10-layer decomposition to denoise the impact signal;finally,according to the characteristics of normal distribution of stress propagation,the binary Gaussian function was constructed for the response value of sensor impact force to the size and position of the applied impact force.The objective function was sampled by Markov chain-Monte Carlo(MCMC)algorithm,and the parameters of the binary Gaussian function were inverted.The sensor impact force response value and the distribution function of impact force size and location were obtained based on the monitoring data.The results show that the error between the monitoring value of the impact force and the impact force applied by the sensitized fiber grating sensor is controlled within 5%,which can meet the requirements of engineering monitoring.According to the impact force and position applied by the experiment,the error between the calculated results of the inverse binary Gaussian function and the monitoring results of the sensor is controlled within 2%,which indicates that the inverse binary Gaussian function can realize the impact force monitoring and accurate positioning of the guardrail.