A Decentralised Braking Force Distribution Strategy for High-Speed Trains

Braking force distribution (BFD) among motor and trailer carriages is essential for guaranteeing braking performance and safety in high-speed trains. A centralised BFD strategy is widely used in modern rail transportation, relying on real-time data transmission among carriages over a communication network. This paper presents a decentralised BFD strategy that eliminates the reliance on communication, thereby reducing the associated costs and complexity, while maintaining the same braking performance with more flexibility. The new strategy is built on two novel ideas: each carriage locally estimates its required braking force using coupler force measurements, and distribution of the calculated braking forces obeying a priority rule is realised by delayed implementation in different levels. The proposed scheme is validated on a hardware-in-the-loop platform and tested under both normal and abnormal scenarios. Results show that the decentralised implementation of the two new ideas achieves electric braking utilisation rates above 99.3% across all cases. Without inter-vehicle communication, the decentralised scheme incurs only a modest tracking error increase (maximum 0.88 km/h), while adhesion utilisation stays within a 3% margin. This means that the proposed method effectively balances performance, communication cost and force prioritisation, thereby offering a robust and practical alternative to centralised framework.