Abstract: Aiming at the characteristics of wide sources, diverse forms, large differences and small quantities of spacecraft fault knowledge, and the defects that the fault knowledge contained in telemetry data during spacecraft operation is difficult to be effectively utilized, this paper proposes an ontology entity bidirectional constrained knowledge graph construction method, which adopts a combination of top down and bottom up approaches to construct knowledge graphs and implement graphical fusion of multi source heterogeneous fault knowledge of spacecraft including telemetry data. At the ontology layer, an improved IDEF5 method is proposed to construct the fault knowledge ontology. At the entity layer, three different knowledge extraction methods are proposed to extract knowledge from (semi)structured data (FMEA analysis table, expert rules), unstructured data (fault texts) and telemetry data, and fuse the knowledge in the entity layer, according to the sources of fault data and the degree of structure. The construction of the fault knowledge graph is realized through the bidirectional constraints and collaborative optimization between the ontology layer and the entity layer. In this paper, taking the spacecraft control moment gyroscope as an example, the fault knowledge graph is constructed and displayed visually by using the above method. The feasibility and effectiveness of the method are verified by a case study.

Key words: fault diagnosis, knowledge graph construction, multi source heterogeneous data, knowledge extraction, ontology construction