Detection of Incipient Leakage Fault in EMU Braking System

The safety of braking system is critical to electric multiple units (EMU). The brake cylinder of EMU is required to provide accurate brake pressure, which is the key parameter that directly affects the braking performance. Currently, the KNORR-based fault detection strategy is used in monitoring the brake cylinders. This strategy is effective for general faults, but ineffective for incipient leakage faults. In this paper, a novel detection strategy is proposed for incipient leakage fault detection, and the method can monitor multiple brake cylinders simultaneously. First, variables with high level of consistency are selected by analyzing the characteristics of the real data from braking system. Then a special linear data transformation is carried out to obtain approximate stationary properties. Finally, a new detection statistic is proposed based on the infinite norm of the transformed data. Experimental studies are carried out on brake test bench to prove the validity of our proposed fault detection strategy.