Objective To improve the operational safety and reliability of the onboard ATP (automatic train protection) system for metro vehicles, and effectively identify and prevent key failure risks of the system, it is necessary to conduct a systematic study on the full-process failure modes and risk links of the onboard ATP system.

Method Taking the onboard ATP system as the research object, a three-level analysis framework of subsystem-component-failure mode is established. The ATP system is divided into five subsystems for analysis, including information acquisition, data processing, communication transmission, control output and human-computer interaction. Based on the actual fault data, the FMEA (failure mode and effects analysis) method is adopted to systematically analyze and identify 14 typical failure modes. The fault causes and failure propagation mechanisms are analyzed from the dimensions of design, manufacturing, operation and maintenance, and environment, and the severity of fault impacts is evaluated. Quantitative assessment is carried out via the RPN (risk priority number) index, and four high-risk links are identified, namely brake control failure, false braking, speed sensor signal drift and wireless communication interruption. Thereby, corresponding prevention and control strategies are proposed.

Result & Conclusion Technical and managerial countermeasures such as heterogeneous redundancy, multi-source information fusion, dual-network hot standby, on-line calibration and preventive maintenance are put forward for each risk link. The proposed mitigation measures can be directly applied to the design and operational improvement of onboard ATP systems.