Abstract: Based on FMECA(failure mode effect and criticality analysis) generated in the design phase of product, through more in-depth, systematic study of the fault diagnosis model, a new algorithm is proposed that can automatically construct fault tree based on FMECA. Research on fault diagnosis knowledge generated by product design knowledge is very significant, which can relieve predicament caused by the lack of diagnosis knowledge. Compared with fault tree structured by hand, the method can acquire fault tree with complete diagnosis knowledge efficiently and exactly.

Key words: FMECA, fault tree, control loop, fault diagnosis