A New Function-Topology-Based Method for Assessing Passive Safety of Mechatronics Systems

Various safety assessment models for predicting the future state of systems based on online monitoring data have been proposed. However, the complexity and interdependencies of mechatronics systems make it improbable to predict and prevent all possible failures/faults. Thus, it is also vital to assess the passive safety of mechatronics systems after a small or local fault occurs in order to make up for the shortcomings of online safety assessment. Hence, this paper proposes a passive safety assessment framework for a holistic system, according to the core chain of events related to component malfunction. The main contributions of this paper include three aspects. First, a component risk coefficient is proposed to more comprehensively reflect the risk degree of the component through analysis of a large number of fault data. Second, the fault propagation mechanism is explored to decrease the subjective effect based on the system topology and fault data. Third, a mapping function between system risk and system safety level is constructed; this function can provide support for management and maintenance personnel. A practical example of the bogie system for a high-speed train is examined to demonstrate the implementation and effectiveness and illustrate a potential application of the proposed passive safety method for assessing mechatronics system safety.