Detection System For Bridge Deck Sleeper Height Based On Rail Trolley

At present,because of the advantages of low cost,light weight and simple construction,most large-span steel truss bridge deck system railway bridges in China are paved with wooden pillows.However,due to the shortcomings such as poor weather resistance and low hardness,wooden bridge pillows deteriorate faster and have a higher failure rate after long-term use,which makes the train potential safety hazards in operation.In order to ensure the safety of train operation,it is necessary to measure the pillow height of open bridge deck regularly so as to evaluate the health status of bridge deck pillow.In view of the time-consuming and laborious use of manual observation method to measure the height of steel truss bridge deck pillow,a measurement system for the height of open bridge deck pillow based on rail trolley is designed and implemented.Firstly,a differential bridge deck pillow height measurement scheme based on laser ranging is designed.Because the measurement results are easily disturbed by the complex background light of outdoor working environment as well as the undulating steering of rail trolley,some methods are proposed accordingly to avoid the interference of sunlight,reduce the interference of white noise of the environment and compensate the attitude.Secondly,the prototype machine for bridge deck pillow height measurement based on rail trolley is designed and implemented.Finally,an experiment was carried out in Nanjing Yangtze River Bridge Railway Bridge Practice Field to test the measuring speed and accuracy of the system.The main contents and research results of the thesis are as follows: 1.Design and implement a bridge deck height measurement system based on railcars.The system consists of two symmetrical bridge height measurement subsystems,each of which includes a phase laser ranging sensor.Attitude compensation module,liquid crystal display module,wireless communication module,etc.2.A differential method for measuring the height of bridge sleepers on open deck is proposed.The vertical difference of the distance between rail surface and steel beam surface can be calculated by the vertical distance between laser distance sensor and rail surface and steel beam surface,so that the accurate height of bridge sleepers on open deck can be obtained.However,the undulating steering of the trolley will lead to different inclination angles of laser ranging sensors at each bridge pillow and introduce additional measurement errors.Therefore,the attitude compensation method is used to correct the measurement results to the vertical pillow height.3.The background light of outdoor working environment is complex.The receiving field of view of laser ranging sensor is easily disturbed by strong background light(such as sunlight)and other light noise,which affects the accuracy of the system.By adjusting the working distance of the laser ranging sensor,the interference caused by strong background light such as sunlight is suppressed.The fast Kalman filtering algorithm is used to reduce the interference of other light noise and effectively reduce the sampling times of single-point measurement.4.The host computer visualization platform matched with the system prototype is designed and implemented,which collects the measurement data of the prototype through wireless mode,and then facilitate the storage,deletion and graphical review of the data.5.The field test has been completed at the training ground of Nanjing Yangtze River Bridge railway bridge.The experiments of sunlight,tilt compensation of laser ranging sensor and differential measurement have been carried out.The experimental results show that the system can effectively avoid the interference of sunlight,reduce the interference of environmental white noise,compensate the tilt of laser ranging sensor and so on.The final measurement accuracy is 1.0 mm.