Automatic Generation Of Geometric Error Inspection Scheme Based On Ontology

Performing geometric error inspection on machined parts is an important job to ensure product quality.The geometric error inspection program is based on the new generation of product geometric technical specifications and certification(Geometrical Product Specification and Verification,GPS)standard,and on the basis of the engineering drawing information of the part,the solution adopted for the geometric error inspection.The inspection plan mainly includes the integration of inspection operations,the recommendation of measuring instruments,and the limitation of inspection conditions.The integration of inspection operations mainly involves: the selection of extraction schemes,the calculation of extraction points,the determination of filtering,and the selection of fitting.Aiming at the problems of high randomness,low efficiency,and large differences in schemes caused by the excessive reliance on the experience of the surveyor in the determination of inspection schemes in actual engineering,this paper proposes an ontology-based automatic generation method of geometric error inspection schemes,the main research content as follows.Constructed the information representation model of the geometric error inspection scheme.From the part engineering drawings or technical documents,extract the part geometric tolerance specifications and geometric feature information,according to the new generation of GPS standards,using the adjacency matrix method to establish a hierarchical geometric error inspection program information representation model.The model from top to bottom is geometric tolerance specification layer,geometric feature layer,extraction scheme layer,extraction point layer,filter layer,fitting layer,measuring instrument layer and detection condition layer.Each layer of information is independent and interrelated,and its mutual relationship is defined by the adjacency matrix.This model lays a theoretical foundation for the ontology representation and reasoning rules of the geometric error inspection scheme.Constructed the ontology representation model of the geometric error inspection scheme.In terms of the established hierarchical information representation model,a sevenstep method is used to construct its ontology representation model.First,summarize and generalize the professional terms in the field of geometric error inspection schemes,then define important terms as classes,and further define the hierarchical relationships of the classes,then define the association relationships in the information representation model as corresponding attributes,and finally define the domain of the attributes.And the value range is restricted.Established the rules for generating geometric error inspection schemes.According to the constructed hierarchical information representation model and ontology representation model,as well as the relevant standards,literature and expert knowledge in the field of geometric error inspection,the SWRL rules generated by the geometric error inspection scheme are established using the Semantic Web Rule Language(SWRL),And studied the generation process of the inspection plan,and verified the feasibility of the method through an example.Designed the prototype system of geometric error inspection scheme based on ontology.In accordance with the ontology representation model and generation rules,Protégé is used to edit its ontology representation model,and the SWRL Tab plug-in is used to write inference rules,thereby constructing an ontology knowledge base automatically generated by the geometric error verification scheme.Facing the ontology knowledge base,using the Jess reasoning engine as the reasoning tool,the structural framework of the prototype system of the ontology-based geometric error inspection scheme was designed,and the operation process of the system was demonstrated with an engineering example.