| With the expansion of the railway traffic, rail lines cross distribution. It can’tavoid the problem of line change in the process of driving, switch is a device whichcan solve the problem, and the electric switch machine is an essential part of theswitch and is a kind of electrical equipment which is used to change the direction ofswitch. A motor is the power equipment of Electric switch machine, the rotation ofmotor converts into translation by the reducer, push or pull the locking bar and switchlock into correct position, so as to achieve the goal of changing switch direction.Along with the constant acceleration of railway transportation, as a railway railtraction device, switch machine must be safe and reliable. In order to ensure the safeoperation of urban rail transit, online and real-time monitoring of locking bar isnecessary for dynamic monitoring of railway switch, including the size and directionof force, conversion rate, conversion time, etc.In fact, the external environment of the subway is so bad, such as interference ofelectromagnetic field, the vibration of the train hit, rain and oil corrosion and otherproblems. However, the existing relevant monitoring system are electrical signals, itis unable to avoid these problems effectively. Optical Fiber Bragg Grating (FiberBragg Grating, FBG) sensor has some advantages of resistance to electromagneticinterference, high sensitivity, good stability, corrosion resistance, long distancetransmission, it is suitable for real-time dynamic monitoring system. Therefore, thisarticle chooses FBG sensors to make sensors to monitor various parameters whichcan reflect the health status when the rail switch machine is in runtime.FBG ring gauge strain sensor is the core of switch machine lock rod dynamicmonitoring system. In this paper, the main research contents include the design andpackaging of FBG strain sensor, sensor installation, the results’ analysis andcomparison with the actual situation. Specific work is as follows.Firstly, on the basis of the principle of fiber grating sensing, verified theproperties of FBG strain sensors through experimental data for many times.Comparing the calibration results of the two different forms of grating, the nakedgrating paste directly and FBG ring gauge dangling paste. Secondly, according to the characteristics of locking bar under stress, design thesensors’ structure conforms to the actual situation. Through experimental calibrationto compare with the naked grating pasted directly and FBG ring strain of platehanging pasted, and then choose the better one. Design a reasonable method oftemperature compensation.Thirdly, because of big stiffness of the locking switch rod and the smallwork strain value in actual situation, we must design a structure which can improvethe sensitivity greatly. We take the method of designing a long distance device to fixthe FBG sensors. The long distance locking rod transmission strain produced tothe FBG strain, and the strain sensing sensitivity increased by7times.Finally, in the city rail train turn out the actual installation of the monitoringsystem, it can dynamically display the stress situation of locking bar in the controlroom when train passes. Select data over a period of time from the results of fieldmonitoring to analyze, get the graph of time wavelength variation, analyze thewaveform diagram, given the change of physical parameters of the monitoring system,and compared with the actual situation.Store these data and set up health threshold. After contrast collection value, itgives the running parameters’ changing situation of locking bar, and it is usedto guide the maintenance of rail equipment and resolve trouble. The operation of thismonitoring system was very successful, monitoring results match to the actualsituation. FBG ring strain sensor with increased susceptibility effect, can dynamicallyand online monitor various parameters of switch machine lock rod, is an innovationpoints of this paper. |
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