Measurement of vehicle ground speed using bogie-based inertial sensors

This paper presents a novel technique for the measurement of vehicle ground speed using inertia sensors mounted on a bogie frame of railway vehicles. The measurement is achieved indirectly from the time shift of the dynamic motions between two wheelsets, by exploring vehicle/bogie dynamic responses to track excitations and extracting particular features of motion at the wheelsets. There is no need for the use of conventional position encoders and therefore difficulties associated with inaccuracies in wheel slip/slide conditions or limited resolutions of the encoders are eliminated. The basic principle of the proposed technique is explained and detailed development of a practical measurement scheme presented. A full performance assessment is provided to illustrate that a fast and accurate measurement of the vehicle speed can be obtained with the proposed measurement scheme. Limitations and further improvements of the new method are also discussed. The method presented in the paper may provide a reliable and accurate measurement of the absolute vehicle speed essential for railway traction and braking control systems and may be extended for automotive applications.