Automatic Precision Assembly System For Hole-peg Compliance Assembly

The miniature products assembly is an important part of precision manufacturing and assembly quality has great influence on products performance. With the rapid development of advanced manufacturing technology, the relatively backward precision assembly restrict the performance and productivity of products. Automatic precision assembly paid more and more study in view of the low efficiency, accuracy and consistency for manual assembly. Hole-peg assemble in production manufacturing has an extremely wide range of applications. For hole-peg miniature parts assembly in contact phase, although a small position deviation which made from environmental factors or assembly systems will cause a large assembly force. In order to avoid excessive force which led to the assembly failure or equipment damage, this paper presents an assembly method based on machine vision and passive compliant mechanisms. Machine vision can detect and control the position at the non contact phase, the passive flexible mechanism can absorb impact energy and compensate the position error at the contact phase from its compliant deformation.An automatic precision assembly system that was developed for hole-peg miniature parts assemble consists four modules: machine vision module, clamping operation module, fixture worktable module, control module. The movable machine visual could accomplish the detection and location of hole and peg parts in different areas; the clamping operation module could complete picking, transporting and assembling parts; the module of fixture and worktable was used for fixing peg parts and storing hole parts; the control module was used for coordination controlling the first there modules to complete the whole assembly process.In this thesis, hole-peg assembly mechanical matrix was established, the process of hole in peg assembly was analyzed and relative factors that have effect on assembly insertion force were calculated and analyzed. A stacked compliant mechanism was developed and its corresponding characteristics were analyzed. Experiments and analysis show that the system can automatic precision assemble hole-peg miniature parts.