Uncertainty estimation of axes direction determination of industrial robot using an ellipsoid concentration model

There is uncertainty while measure different geometrical elements of industrial robots, multi-axis machines or other complex mechanisms during their calibration using CMM. This uncertainty has a large number of components. It is extremely difficult to estimate this uncertainty using ISO [12]. This article represents approach for uncertainty estimation of axes direction determination of industrial robot. We revealed the concentration ellipsoid - a geometrical view of the spatial spread of error after repeated axis determination of an industrial robot. The mathematical model of the concentration ellipsoid was developed. In this paper we have analysed the big axis value of the concentration ellipsoid using a 3D surface. An iterative uncertainty search algorithm for the industrial robot's axis and its exit criterion was developed. Uncertainty of each axis of the industrial robot was estimated. The standard deviation of the iterative algorithm of uncertainty was calculated. The dependence of uncertainty from increasing the rotation radius of the measuring device reflector was experimentally revealed.