Study On Kinematical Measurement Technology Of Line Geometry In Railway Safety Detection

As an important national transportation infrastructure,railway and its traffic safety are of great importance to national economy and people's daily lives.Historical data show that geometries of railway lines are the most important parameters indicating the status of traffic safety.As railway develops toward higher speed and heavier traffic density,on-board kinematical detection methods have become the major means in safety monitoring.Its key technical problems include non-contact detection and high-accuracy referencing technologies for kinematical measurement.The kinematical measurement of complete line-profile is taken as an example in this dissertation and the principles of non-contact detection of line safety and high-accuracy reference acquisition for kinematical measurement are discussed in both theoretical and practical points of view, providing a basic solution for key problems in kinematical detections of railway safety and thus having great significance in both theoretical and practical aspects.A new algorithm is proposed in the dissertation for inertial referencing based on vehicle-track vibration model.This algorithm utilizes KF/UKF algorithm and makes full use of known features of tracks,vehicles and sensors,resulting in significantly improved measurement accuracy over the traditional inertial referencing system. Numerical simulations show that this new algorithm has advantages of good convergence and real-time processing ability.A ground-assistant position-pose measurement method,with a reflecting mirror set on ground and laser,imaging and detection equipment on board,is also proposed to measure the instantaneous position and angular displacements of a moving rail-guided vehicle with respect to ground referencing points.Based on these two new methods,a kinematical referencing strategy, consisting of both ground-assistant instantaneous position-pose measurement and on-board inertial referencing techniques,is then proposed in the dissertation to provide corrections at fixed points for errors accumulated over time in traditional inertial referencingFinally,the application principles and methods for propagation-time-based laser scanner used in the field of complete line-profile measurements are studied.A new calibration method based on 1-D coordinates is proposed,with much higher accuracy than traditional 3-D coordinates-based methods.Furthermore,the proposed new methods for inertial referencing and ground-assistant instantaneous position-pose measurement are used to make high-accuracy kinematical measurements for railway infrastructure,and good results are obtained in engineering projects of complete line-profile measurement in Line 5,Line 10 and Airport Line of Beijing Metro and Beijing-Tianjin high-speed railway.