Kinematic Analysis of Contact State Transitions in Assembly Operations and Automatic Generation of Transition Network

A new approach to the kinematic analysis of rigid body motion in assembly operations is presented. An assembly operation is expressed as a successive transition of a state of contact between an assembly object and constraint points. A graph termed Contact State Network is introduced to describe the transition of a contact state. Each node of the graph corresponds to a contact state. An arc between a pair of nodes means that the assembly object can transit directly from one node to another. Using the contact state network, an assembly operation is represented by a path of the network going from an initial node to a goal node. When the contact state network is complicated, systematic generation of the network is eagerly required. An algorithm for automatically generating the network from geometric data of assembly parts is developed using admissibility conditions for direct transitions.