| The complexity of machinery products and the empirical of the Assembly process planning Lead to a high degree of complexity of virtual assembly. For " the growing complexity of virtual assembly information space and process information administrative tasks" and "the contradiction between the interactive channel with limited bandwidth and human limited cognition and information processing capabilities.In this paper, "The thinking of "human-centered" in Pervasive Computing was inducted into the virtual assembly environment, putting forward the "context-based, perceived as the core" to achieve a certain intelligent computer-aided assembly process planning system concept. To achieve the system, it comprehensively applied Ontology, Artificial Intelligence, Agent technology as tools, and flexibly applied XML technology.From the context expression construction context, context reasoning, context applications to system integration five step-up level,it explored and researched the virtual assembly process planning system based on context perception systematicly. By 3D-IVAPP prototype system exploitation, the paper presents the theory and key algorithm integrated authentication. The paper's main works are as follows:1. The Construction of Ontology-based Context Aware FrameworkBased on the analysis of the impact factors of assembly process planning and the classification of knowledge of the assembly process, the connotation and extension of the assembly context were discussed, the relationship between the knowledge of assembly and assembly context was presented, the assembly context hierarchical model was established, Ontology-based context aware framework was built combining with CTK, by proposing the concept of intelligent small-world situations faced to virtual environment, designing the framework and working model of Assembly context based on Ontology, constituting the function module and key technologies for the intelligent assembly system2. The Ontology Modelling of Intelligent Assembly context information Through the analysis of the traditional method of assembly design CAD system, the multi-level assembly model was designed based on virtual assembly, which the assembly semantic information extraction process was analyzed on the basis of; After analysing the ontology concepts, construction guidelines methods, and Ontology Language Semantic,the establishment of this assembly model in the ontology areas vocabulary given the concept of assembly-level ontology relations; it analysed the information map of the CAD system to the semantic model, established the process of the semantic information extraction algorithm based on solidwork by giving the example applications, and application of set theory, encapsulated the assembly context information model using the set theory.3. Ontology reasoning and intelligent WidgetsBy a comprehensive analysis, comparing the OWL-DL, and SWRL reasoning in the semantics of their strengths and weaknesses, it designed DLSL SWRL reasoning program based on OWL-DL combining to SWRL, established OWL ontology knowledge base and SWRL rule base, which were inducted into Jess inference engine, described the rules of parts-assembly belong-to relationship, concept of consistency testing the degrees of freedom of assembly. After the instance analysis by using the DLRL reasoning engine, the ontology instances of intelligent fastening method was proposed, it presented intelligent parts identification algorithms, benchmark parts and parts to be installed intelligent aware algorithms based on assembly tasks, which provided an effective means of perception of intelligent assembly tasks.4. Assembly context-aware mechanismsBased on the needs analysis of context recognition acquisition, this paper proposed a multi-granularity design of the context, and set up a multi-granularity module of the assembly context, and introduced a multi-granularity algorithm based on entropy space. And in this paper, based on the features of virtual assembly, the task-aware is pointed to be the core of the virtual assembly context aware, and the relationship between the tasks and the roles during assembly is analyzed, what's more, multi-agent system and its request response model is build, and the assembly context aware mechanism for multi-agent system is proposed.Finally, based on the context aware, a virtual assembly process planning system model (3D-IVAPP) is designed and developed, including 3D virtual model from the solidworks, semantic information, smart assemble fasteners algorithm in virtual environment with open inventor, user data, rights management, sharing and visualization of 3D model on the Web platform of technology resource management. What's more, the research ideas, methods and the key algorithm are introduced at the end.
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