Research On Methods And Systems For Dynamically Measuring Parameters Of Train Wheels

The wheels of trains are key components that play an important role in the safety of rail transportation.With the increasing of train speed,train wheel wear becomes more and more severe,which could cause danger and lost of life and wealth.Thus the study the method for dynamically measuring the parameters of wheelset and the development of such a measurement system is a key problem that must be firstly solved before repair of train-wheels according to condition could be realized.It is also a difficult problem and has not been solved propedy due to the worse environment and a very limited space for the measurement. This dissertation is focusing on solving this problem and developing a system for dynamically measuring the geometric parameters of the wheelset with the support of the fund from the Ministry of Railway.The main work and achievements in the dissertation are as follows:1.A novel method using the laser displacement sensor to dynamically measure the wheel's diameter is presented and the device for dynamically measuring the wheel's diameter is developed.As the measurement of wheel diameter is the one of most difficult points in the dynamical measurement of geometric parameters of wheelset,three methods to measure wheel's diameters are presented and the relative measurement devices are developed.Based on theoretic analysis and the experimental results,the best method for diameter measurement is to adopt two laser displacement transducers.The measurement error is analyzed in theory and simulation is made.The feasibility of this method is testified by the comparison between measurement datum obtained by the developed system and by hand.2.By use of several sets of parallelogram mechanisms,the device for dynamically measuring wheel's tread abrasion and abrade is developed.Based on static and dynamic analysis of parallelogram mechanisms,simulation is made,and the method to control the vibration of parallelogram mechanisms is presented.3.Two methods to dynamically measure the wheel rim are presented,which is based on image processing and laser technology separately.The device which can measure thickness of wheel flange,rim width and inside width of wheelset is developed.4.The measurement system for dynamically measuring geometric parameters of wheelset is developed.With this system,the geometric parameters such as wheel diameter,tread abrasion and abrade,flange thickness,trim width and inside width of wheelset can be obtained when the train passes thorough the measurement system that is mounted alongside the rail-truck The feasibility of this measurement system is proved through repeatability measurement experiments and measurement datum comparison between the system and manual work.