Sensitivity Analysis of an Overconstrained Parallel Structure Machine Tool, the Tripteor X7

摘要

A main limitation of parallel kinematics machine tools (PKM) use for machining tasks is their accuracy low level mainly due to geometrical transformation errors. Indeed, such machine tools are geometrically controlled with an inverse kinematics model (IKM). For a large number of PKM, this IKM is defined with an analytic method and by introducing geometrical parameters. Thus, the influence of each geometrical parameter on the tool pose accuracy should be estimated via a sensitivity analysis. In the case of an overconstrained PKM, the IKM is generally computed with a numerical method. The sensitivity analysis leads to complex computation. The aim of this paper is to present a sensitivity analysis on the Tripteor X7, an overconstrained machine tool. This study is also a first step to define the geometrical identification method on this overconstrained mechanism.