Assembly planning and plan decomposition in an automated microrobot-based microassembly desktop station

Abstract

There is an increasing interest in performing assembly of microsystems (i.e., non-destructive transportation, precise manipulation, and exact positioning of microcomponents) by flexible mobile microrobots which provide the necessary accuracy. The spectrum of tasks in microassembly ranges from simple preparatory operations like applying adhesives, drawing adjustment marks, cleaning objects, to the performance of the final assembly and inspection of the finished microsystem. An automated microrobot based microassembly desktop station (MMS) may offer the desired features and versatility. The main problems of realizing an MMS are intelligent assembly planning on the uppermost control level and task-specific allocation of assembly operations to robots and tools to allow the assembly process to be free of error and collision. The basis functions are described for the MMS that is being developed at the University of Karlsruhe. After discussing microassembly planning in an MMS a common microassembly model is introduced, based on geometric reasoning. For all planning steps – the generation of feasible assembly sequences, selection of the best assembly plan and allocation of the assembly operations to the robots employed by an MMS – a detailed description of the algorithms is presented, so they can be used by the practitioner. Finally, the general structure of a microassembly planning system of an MMS is introduced and the function of each system level is explained.