Mereotopological assembly joint information representation for collaborative product design

In this paper we discuss an ontology-based representation method for differentiating assembly joints in collaborative and intelligent product design. As design becomes increasingly knowledge-intensive, intelligent, and collaborative, the need becomes more critical for computational frameworks that enable product development by effectively supporting the formal representation, capture, retrieval, and reuse of product knowledge. Joints are a key aspect of assembly models that are often ambiguous when model sharing takes place. Although various joints may have similar geometries and topologies, the physical implications of the selected joining processes may vary significantly. It is possible to attach notes and annotations to geometric entities in order to distinguish joints; however, such textual information does not readily prepare the model for downstream activities, such as simulation and analysis. As an illustration, analysts must read and interpret the annotations in order to develop the appropriate boundary conditions. In this work, we present an assembly design ontology that explicitly represents assembly constraints, including joining constraints, and infers any remaining implicit ones. By relating concepts through ontology technology rather than just defining data syntax, assembly and joining concepts can be captured in their entirety or extended as necessary. By using the knowledge captured by the ontology, similar looking joints can be differentiated. For this research, we used a mereotopology, which is a region-based theory for parts, and the Semantic Web Rule Language (SWRL) to represent the difference of joints and to define assembly design terms and their relationships. We also used SWRL so that the joining rules can be reasoned to differentiate assembly joints. Finally, by using an ontology, various geometrically and topologically similar joints are successfully differentiated in a standard and machine-interpretable manner.     

Ontology-based assembly design and information sharing for collaborative product development

To realize a truly collaborative product design and development process, effective communication among design collaborators is a must. In other words, the design intent that is imposed in a product design should be seized and interpreted properly; heterogeneous modeling terms should be semantically processed both by design collaborators and intelligent systems. Ontologies in the Semantic Web can explicitly represent semantics and promote integrated and consistent access to data and services. Thus, if an ontology is used in a heterogeneous and distributed design collaboration, it will explicitly and persistently represent engineering relations that are imposed in an assembly design. Design intent can be captured by reasoning, and, in turn, as reasoned facts, it can be propagated and shared with design collaborators. This paper presents a new paradigm of ontology-based assembly design. In the framework, an assembly design (AsD) ontology serves as a formal, explicit specification of assembly design so that it makes assembly knowledge both machine-interpretable and to be shared. An Assembly Relation Model (ARM) is enhanced using ontologies that represent engineering, spatial, assembly, and joining relations of assembly in a way that promotes collaborative assembly information-sharing environments. In the developed AsD ontology, implicit AsD constraints are explicitly represented using OWL (Web Ontology Language) and SWRL (Semantic Web Rule Language). This paper shows that the ability of the AsD ontology to be reasoned can capture both assembly and joining intents by a demonstration with a realistic mechanical assembly. Finally, this paper presents a new assembly design information-sharing framework and an assembly design browser for a collaborative product development.