Measurement of vehicle ground speed by exploring vehiche dynamics

EPSRC/RRUK grant. PI – Professor T X Mei

The speed of a vehicle is normally measured by sensing the rotational speed of the wheels through the use of slotted discs mounted onto the wheels or in railway vehicles through detecting the number of teeth of a traction gear box. As a standard practice for many years, this conventional approach is  considered to provide sufficient accuracy as long as there is no excessive wheel slip or slide – a phenomenon that causes wheels to rotate much faster or lower than the equivalent of the vehicle.

This project carries out a more detailed study into a novel concept, originated by the PI at Salford University (Professor T X Mei), and the overall aim of the proposal is to establish an important foundation for the study of a reliable and low cost technique for the measurement of train ground speed  that will not be compromised in the wheel slip or slide conditions. The new method derives the train speed from time shifts between the vertical motions of two wheels of a vehicle/bogie, which are in turn estimated using measurement signals from two inertial sensors mounted on a vehicle/bogie frame.  This may be further enhanced with data fusion with wheel based encoders to reduce measurement delays at extremely low speeds and to improve the measurement robustness.

This project is funded by EPSRC (UK) via Rail Research UK grant.

Principle of the new measurement method