Random Insertion Mechanisms

Abstract

At the level 0 of the general architecture of a production line (see Figure 1.1), a delicate problem in production line design concerns the flexible automation of very accurate assembly operations. While robotization offers the possibility of solving several practical problems, it often remains to overcome tedious difficulties such as the insufficient accuracy and repeatability in the performance of the manipulators, the inaccuracies in the gripping and the presentation of pieces, part-tolerances, etc. In particular, it often happens that the precision required to mate the parts is far below the robot’s repeatability, especially when precise and chamferless insertions are considered. By repeatability, we mean the ability of a given manipulator to be cyclically commanded to attain an arbitrary fixed target. Among the solutions proposed, let us mention the vibratory method. This general philosophy consists in vibrating one of the parts in order to absorb relative misalignments. The vibrations enable the work tool to systematically explore a planar neighbourhood of fixed size in which the position errors between parts are confined. The approximate alignment, which enables the mating to be performed, is achieved when the distance between the parts is less than the characteristic clearance. This general problem has been recently discussed in the following references: [HF], [WA], [JE], [IV], [BD1], [BD2], [SC].