Spatiotemporal semantic knowledge system for intelligent assembly sequence planning

Rich spatiotemporal semantic knowledge is contained in the process of product modelling and assembly. Spatiotemporal semantic knowledge system is studied from the aspect of spatial topology and temporal topology for assembly sequence intelligent planning. The product spatial semantic knowledge model are build, including four levels assembly spatial objects of product, assembly, feature and geometry entity, and three categories assembly spatial semantic of layer, structure and constraint. Assembly operation is taken as time object. Temporal semantic knowledge is described with time point and time period topological relationships of time object. The association of spatial semantic knowledge and temporal semantic knowledge can be expressed through the structure semantics of spatial object and the structure achieved by assembly operation of time object. Spatiotemporal semantic knowledge model is proposed to provide the theoretical basis for assembly sequence intelligent planning. The knowledge acquisition of engineering semantic is studied from the CAD model. Ontology model of spatiotemporal semantic knowledge is built with protégé. The spatiotemporal semantic knowledge system for assembly sequence intelligent planning is established to provide technical foundation for assembly sequence intelligent planning based on knowledge retrieval and rule reasoning. The spatiotemporal semantic knowledge system example of elevator floor lock device for assembly sequence intelligent planning verified the effectiveness and feasibility of the proposed spatiotemporal semantic knowledge model.