高速高精度钢轨超声检测系统研制

Ultrasonic detection technique is a necessary method to ensure the operation safety of railways. .To date, most of domestic detectors are hand-push sliding type. The probes need to be close to rail for detection. In spite of its high detection accuracy and low signal loss, it suffers severe abrasion and low speed. Whereas, the probe of the imported wheel-type automated detector is attached to an axle. Since the supersonic need to transmit through media like liquid, rubber and rail etc, the long run distance results in signal reduction and low precision. Besides, its speed is limited owing to avoiding echo loss..This project adopts novel structure and algorithm to develop high speed and high accuracy automated rail flaw detection system based on ultrasonic technology. 1. Employing crawler-type suspender structure. The probe contacts closely with rail reducing signal loss. The immobility time between probe and rail is guaranteed. Doppler effect and echo loss are avoided even at high speed. 2. The frequency band modulation and parameter estimation algorithms approaching the theoretical bounds are proposed to perform near field detection. In addition, rapid detection can be achieved in the single input multiple output (SIMO) mode. High accuracy and robust “Post-focusing” processing is conducted via high-performance computing. 3. Armed with PVDF components and the UWB technique, the flexible wireless crawler-type probe is equipped..This project has sufficient preliminary studies. The theoretical analysis proves that at the speed of 300km/h, the detection accuracies of this system meet national standard.

超声钢轨探伤是保证铁路安全的必要手段。.目前国产以手推滑动式探伤仪为主。工作时，探头直接接触钢轨，信号损耗低，检测精度高。但摩擦严重，速度慢。进口轮式机动探测仪，探头固定在轮轴上。工作时，超声波须经过液体、橡胶、钢轨等多介质，信号游程长，损耗大，精度低；为避免回波丢失，速度不能太快。.本项目采用创新结构及算法，研制高速高精度钢轨超声检测系统，①采用履带式挂件结构，探头与钢轨紧密接触，信号损耗小；探头与钢轨间存在足够静止时间，高速运行时也不存在多普勒效应，且回波不会丢失；②采用逼近理论性能界的调频参数估计算法，实现近场高精度探测；采用单发多收阵列工作模式，检测时间短；用高性能计算进行后聚焦处理，精度高、鲁棒性强；③采用PVDF薄膜器件和无线超宽带传输技术，实现无线履带式探头，灵活方便。.本项目已有充分前期基础，理论分析表明，本系统在300公里时速，各项检测精度符合钢轨检测行业国标。

超声钢轨探伤是保证铁路安全的必要手段。目前国产以手推滑动式探伤仪为主。工作时，探头直接接触钢轨，信号损耗低，检测精度高。但摩擦严重，速度慢。进口轮式机动探测仪，探头固定在轮轴上。工作时，超声波须经过液体、橡胶、钢轨等多介质，信号游程长，损耗大，精度低；为避免回波丢失，速度不能太快。本项目采用创新结构及算法，研制高速高精度钢轨超声检测系统，取得的主要成果有：1.提出分体式无线探测架构，探测前段可降低成本与体积，而后台用高性能计算进行后处理，精度高、鲁棒性强。2.研究了宽频一体化无线探头关键技术，可满足无线探头的宽频带、小型化、低功耗的工程需求。3. 优化设计了逼近香农界的宽频探测信号,并提出逼近Cramer-Rao Bound参数估计理论界的参数估计算法，实现近场高精度探测；4.开展探测数据无线传输系统的射频模块研制，提出了系列新型理论分析及小型化低功耗设计理论与方法.5.基于项目新架构体系，研制出原理样机，其各项检测精度符合钢轨检测行业国标。