The use of a kinematic model to analyze positional tolerances in assemblies

Abstract

The utilization of robots, for mechanical part assemblies, is a current practice. Existing methods and software permit to simulate tasks and program them off line using the perfect geometry of the parts. However, as the parts to be assembled are never perfect the adjustment time of these programs is often too long. It is indispensable to find models that can integrate these manufacturing uncertainties at the simulation level. The method proposed can replace the verification using manual functional gauges and can be integrated to a simulation software. In relation to the existing methods, it is especially suitable for the intended parts to be assembled and the datum reference frame (DRF) is defined at maximum material condition. This paper proposes a method for all situations of the DRF where the part is in conformance. It can be applied to inspection, as well as to tolerance analysis and synthesis. A kinematic model is used to represent the permissible motion of the DRF.