Research And Implement On Online Detecting The Geometric Parameters Of Wheelset Based On Optical Perception

Wheelsets are the key parts which couple railway vehicles and tracks,and their state situation has great influence on railway traffic safety.When vehicles are running on the rail,the rail would rub against and wear away the tread and flange of wheels.As a result the geometric parameters of wheelsets would be changed.the changes would have a huge impact on vehicle performance and operation safety.So it is of realistic significance to measure the geometric parameters promptly and accurately.This paper proposes an online deceting system for the geometric parametersof wheelsets based on optical perception.The main contents and achievements of the dissertation are as follows:(1)The light-path of the online deceting system is designed.Firstly,the principle of optical perception is introduced,and the infulence factors of detecton are analyzed.Then,the detail related parameters of the light-path are identified,and the relationship between central angle and precision are proposed.Finally,the light-path of the system is designed according to the influence of the sensors'projection angle,yaw angle and installment location,and the relative positions and angles between sensors and wheelsets are determined.(2)The algorithm of the online deceting system isproposed,which includes static detecting algorithm and dynamic deceting algorithm.Statical gorithm involves coordinate transformation,data fusion,curve fitting and extreme point extraction.Dynamical gorithm involves data segmentation,wheel diameter optimization,tread optimization and train speed compution.The simulation of static and dynamic deceting algorithms is carried out based on computer simulation data,and simulation results verify the effectiveness of the online detecting algorithm.(3)The error analysis of the online deceting system is studided,which includes wheel diameter detecting error and rim detecting error.In wheel diameter detecting error analysis,the random error of laser sensor and the rim vertex coordinate error are both taken into consideration.The wheel error propagation ruleis derived according to the diameter circle equation,and wheel diameter detecting error can be determined.The error analysis results indicate that the wheel diameter detecting error can meet the requirements of on-site maintenance.In rim detecting error analysis,the relative position of sensors,deflection angle,precision and the non-over lapping between detection surface and wheel center areall considered.Computer simulation is carried out to analyse the rim detecting error.Based on the error analysis,the installation requirements which can meet the design performance are obtained.(4)The implementation and field experiments of the online deceting system are carried out.Firstly,the system architecture and mechanical structure are designed,and the overall structure of the real-time monitoring and early warning sytem of urban trains is listed.In the low-speed experiments,the measurement results of the system are compared with that of Guangzhou Institute of Measurement,and the comparis on verifies that the system has a high accuracy.In the high-speed experiments,the measurement results of the system are compared with the manual measurement results,and the comparison validates that the system has a high consistency and repeatability.It can replace the manual measurement.Finally,wheel diameter measuringt experiments at high speed are conducted on trial operation line.Three groups of laser displacement sensors are used to measure wheelset,and the feasibility at high speed of the system is also verified.Experimental results show that the system is able to collect data and measure the wheelset size when the train is running at the speed of 40km/h,and has high stability and accuracy of measurement results when the train is in high-speed operation.(5)The online diameter deceting method is proposed based on multi-sensor fusion technique.Two laser displacement sensors and one eddy current sensor are used to measure wheel diameter online.According to the simulation data,the detecting algorithm of the system is designed and the mearuring error is analyzed.Finally the field experiment is carried out.The measuring accuracy and repeatability is analyzed according to the result of the wheelset set and real train experiments.