Abstract: In order to improve fidelity for virtual assembly system, research on physically-based virtual assembly process is proposed. Physically-based model for parts and components is created by analyzing the requirement of virtual assembly process on physical property of parts and components. The calculating method of basic physical property is given. Physically-based free motion navigating and collision response is discussed and the method to establish free motion state is given. Interaction process among assembly objects in virtual assembly system and the approach to analyzing local steady status for assembly objects are researched based on analyzing physically-based virtual assembly process. Analysis for dynamics and kinematics in virtual assembly process is committed using multi-body system dynamics and the equations for dynamics and kinematics are presented. Kinematical pair constraint is expressed by using basic constraint equation which is converted from abstract constraint relations. Kinematical pair constraint is used in further kinematics analysis for assembly objects. The steady state analysis approach based on collision and static is given and used to research the conditions for steady state of assembly objects. Application instance manifests that the method mentioned above is feasible and effective.

Key words: Assembly process, Dynamics, Kinematics, Physically-based model, Virtual assembly, Virtual reality