Abstract: A novel approach to measuring the criticality of degradation components is proposed in this paper to specify the contributions with regard to the decline of system reliability. Firstly, linguistic variables which are expressed by fuzzy set with grey number elements are introduced to assess the reliability of degrading components. Then the reliability of system is obtained based on structure functions. Thirdly, the cooperative game theory is employed to explore how a specific degrading component contributes to the degradation of system reliability in the context of uncertainty. The operations of fuzzy set and grey number are both used to obtain the component criticality. At last, an illustrative example about a newly-developed exoskeleton robot is presented to demonstrate that the proposed method is more rational and effective on measuring the criticality of components in the context of uncertainty.

Key words: Criticality Analysis, Cooperative Game Theory, Fuzzy Set with Grey Elements, Reliability Evaluation