Fault detection of EMU brake cylinder

摘要

The air brake system is crucial to guarantee the safe operation of electric multiple unit (EMU) due to its high-speed characteristic. As an important device of the EMU air brake system, brake cylinder has a direct influence on the braking action. Brake cylinders are usually equipped with measurement sensors so as to monitor their pressures. Currently, univariate control chart is utilized to monitor each brake cylinder. That is, the brake cylinder is deemed as faulty if its pressure is beyond the permitted range. Sensor damage can also be easily detected by the detection circuit. However, the performance degradation of brake cylinder and soft sensor fault are not well handled by current monitoring strategies. In this paper, a new multivariate detection index called inter-variable variance (IVV) is proposed to monitor multiple brake cylinders simultaneously. The IVV is capable of detecting the performance degeneration of brake cylinder, as well as the soft sensor fault. Besides, these two types of fault can be distinguished from each other by making use of additional information. Experimental studies are carried out to demonstrate the effectiveness of the proposed fault detection strategy.