Simulation analysis of the sources of inaccuracy of a parallel manipulator

Parallel robots are reliable tools used in the high-precision industry because of their good positioning performances. Recently, requirements in. absolute accuracy with this kind of manipulators has reached the nanometer scale. In order to obtain such performances, it is imperative to have a precise knowledge of the different sources of inaccuracy, such, as manufacturing errors, gravity effects and thermal variations. This information can be obtained using numerical simulation models. In this paper, we are interested in the modelling of the sources of inaccuracy mentioned, above (static analysis). A case study of a linear axis robot is presented. It is shown that inaccuracies resulting from gravity and manufacturing errors arc major issues that, must be considered in order to obtain nanometer accurate motions.