Automatic assembly of three-dimensional structures via connectivity graphs

Abstract This paper describes a new system for automatic assembly which is capable of dealing with 3-dimensional structures (assemblies) and sub-structures. The system accepts the definition of a structure by means of a CSG (Constructive Solid Geometry) tree and uses a geometrical modeling language to create the support and connectivity graphs for the structure. Based upon these graphs, the system checks whether a defined structure is valid and stable and then automatically generates the assembly sequence required in order for a robot to assemble the structure. The system is capable of dealing with three cases: (1) single-movement assembly of a body; (2) multiple-movement assembly of a body; and (3) single and multiple movement assembly of sub-structures. The system assumes straight line movements along the principal axes and provides the assembly sequence for each axis and direction separately.