【作者】 高伟；

【导师】 程轶平； 刘泽；

【作者基本信息】 北京交通大学 ， 交通信息工程及控制， 2017， 硕士

【摘要】 钢轨探伤是利用无损检测技术去检测钢轨表面、内部、底部和腰部等处的损伤。由断轨而导致的铁路事故时有发生,鉴于铁路运营的安全性,进行钢轨探伤意义重大。目前,主流的前端检测技术有超声波探伤和电磁探伤。国内探伤任务主要以手推式超声波探伤仪为主,大型钢轨探伤车为辅的方式来完成。超声波探伤以检测轨腰和轨内损伤为主,而轨面浅表层和轨底则属于超声波探伤的盲区。虽然手推式超声波探伤仪探伤的准确度高,漏检率低,但是探伤过程中需清洗轨面,并确保探头与轨面紧密接触,需有经验的专业人员来操作。因此,探伤效率低,且对钢轨探测环境要求苛刻。现有的探伤设备无法满足铁路安全运营的需要。因此,本文设计并实现了一种新型的车载钢轨探伤方案,且在茶坞工务段进行了实物验证,具有重要的实际意义。本文的主要工作如下:(1)设计了一种将电磁探头小型化和车载化的新型钢轨探伤方案。伴随着列车的行驶,可实时控制电磁探头时刻保持相对钢轨5mm的距离,有效抑制了电磁钢轨探伤的提离效应,从而实现了在线实时探伤。(2)机械部分:该平台由围绕两运动轴及电磁探头的多个机械部件组成,具有三个可调自由度。创新的地方有:L型探头设计、垂向防撞橇设计和水平向钓鱼法机架设计。L型探头可使线圈同时覆盖钢轨正面和侧面,垂向防撞橇避免了探头经过两轨接缝时与钢轨相撞,水平向钓鱼法机架确保探头随振动力自适应通过岔道。(3)硬件部分:设计并搭建出了控制电路盒。主要包括线性电源电路、电压转换电路、电机驱动电路、通信接口电路、测速传感器和电涡流位移传感器等。(4)软件部分:首先,移植linux系统到iMX283控制器,编写部分硬件驱动。其次,实现了通信接口、数据分析存储、涡流测距、闭环控制系统、控制算法、多线程等代码。最后,编写Qt GUI来显示传感平台运动状态和设置控制算法参数。(5)控制算法方面:分析计算列车行驶时车体振动量、分析出了探头的空间受等效受力模型。在iMX283控制器上实现PID控制算法,且在列车低速运行时实际调试了算法参数。探索在微控制器上实现迭代学习PID控制算法并调试算法参数。最终,将本文设计完成的传感平台成功地安装于低速货车上,且实现了随动运动控制。主要目的在于验证该探伤方案的可行性,为以后将传感平台应于高速列车奠定了基础。更多还原

【Abstract】 Rail flaw detection is to detect the damage of rail by non-destructive detection technology.Railway accidents caused by broken rail often occur.In view of the safety of railway operation,rail flaw detection is significant.Currently,the mainstream front-end detection technologies are electromagnetic flaw detection and ultrasonic flaw detection.Hand push type ultrasonic flaw detector is used as the main method,and the large rail flaw detection vehicle as a supplement in domestic flaw detection task.The ultrasonic flaw detection method focuses the flaw in inner rail and rail waist.However,the surface of the rail and the bottom of the track belong to the blind area for ultrasonic flaw detection.The detection accuracy is high;the missing rate is very low for hand push type ultrasonic flaw detector.But it needs to clean the rail surface in the process of detecting,and ensure that the probe keeps in close contact with the rail surface.Thus,it needs to be operated by experienced professionals.So the detection efficiency is very low,and harsh environment is need for rail detection.The existing flaw detection equipment can not meet the demand of safety for railway operation.Therefore,a new type of onboard rail flaw detection scheme is designed and implemented in this thesis,and verified in Chawu Permanent Way Depot,which is significant in practice.The main work of this thesis is as follows:(1)A new kind of onboard rail flaw detection scheme whose electromagnetic probe is miniaturized and on-boarded is designed.With the train running,the distance of 5mm between the electromagnetic probe and the rail can be kept in real time to eliminate the effect of vehicle vibration to the measured signal.Thus,the on-line real-time flaw detection is implemented.(2)Mechanical part:the platform with three adjustable degrees of freedom consists of many mechanical components surrounding the two axes and electromagnetic probe.Innovations include:the design of L-type probe,the design of vertical anticollision ski,the design of rack by horizontal fishing method.L-type probe can make the coil cover the front and side of the rail at the same time.Vertical anticollision ski is used to avoid the probe over the track when the two rail joints with the collision.Horizontal fishing method to ensure that the probe chassis with vibration force adaptive through the fork.(3)Hardware part:the control circuit box including linear power supply circuit,voltage conversion circuit,motor drive circuit,communication interface circuit,speed sensor,eddy current displacement sensor is designed and built.(4)Software part:first of all,transplant Linux operating system to iMX283 controller;write part of the hardware drivers.Next,the communication interface,data analysis storage,eddy current measurement,closed-loop control system,control algorithm,multiple threads and other code is implemented.Finally,the Qt GUI is designed to show the motion state of the sensing platform and set the control algorithm’s parameters.(5)Control algorithm:analysis and calculation of vehicle body vibration,the equivalent space force model of probe is analyzed.The PID control algorithm whose parameters are actually debugged when the train is running at low speed is impmented in the controller of iMX283.This thesis explores the iterative learning PID control algorithm and debugs the algorithm parameters on the microcontroller.Finally,the completed onboard flaw detection sensor platform is successfully installed on the low speed train,and the servo control is realized.The main purpose is to verify the feasibility of the flaw detection scheme,and lay the foundation for further application in high speed train.更多还原