Study on Dynamic Measurement Method and Application of Rail Surface Slope and Vertical Curve Radius for High Speed Railways
To reveal the changes in railway profile parameters of high-speed railways and the relationship between railway profile,track irregularity and subsidence of subgrade and bridges,this paper proposed a dynamic measurement method for rail surface slope and vertical curve radius based on inertial measurement unit(IMU),in response to the lack of dynamic inspection equipment for parameters of railway profile in China.Firstly,the bogie frame coordinate sys-tem and IMU coordinate system were established,to align the two coordinate systems based on the minimal correlation between gravity acceleration and horizontal acceleration.Secondly,the rail surface slope was calculated by bogie frame longitudinal acceleration.The train pitch motion and longitudinal inclination error with the track plane were compensated.Then,the vertical curve radius was calculated based on the slope measurement value.Finally,experiments using a high-speed comprehensive inspection train were conducted on a newly built high-speed railway in China.The results show that the absolute mean deviations of slope and vertical curve curvature repeatability are 0.07%o and 0.71×10-3 rad/km,with respective range of 0.22%o and 0.005 rad/km.