Friction Estimation for Railway Brake Systems in Field Tests

Abstract

Condition based monitoring concepts for railway brake systems offer a row of promising advantages: improved safety, reduced noise emission, and economic benefits by an optimal utilization of every single brake unit. However, a reliable determination of the current state of the brake components is difficult due to the rough operating conditions and the economic effort of a direct, optical identification. To ease the conflict between the economic restrictions, the required accuracy of the information, and the robustness of the measurement equipment, the current work presents a model-based observer design. This observer estimates the friction coefficients between brake disc and brake calipers for every wheelset of a train. To enable a railway-compliant and economically reasonable implementation, the observer configuration relies on a set of robust sensors, which are mostly used in modern trains. Furthermore, the influence of the train resistance on the longitudinal dynamics is taken into account to minimize the disturbance in the evaluation of the actual brake friction coefficients. In a next step the information on these friction coefficients can be used to display a maintenance alarm for not properly working brake equipment.