Experimental Results for Kuka Repeatability Measures and Comparison with the Stochastic Ellipsoid Approach

In this paper, we display experimental results about the measurement of repeatability of an industrial Kuka robot. We first study the distributions of the angular positions and show that these distributions can be considered as Gaussian. We compute repeatability in different locations of the workspace using the experimental angular covariance matrix and the stochastic ellipsoid modeling. We measure repeatability and observe a high variability. We explain the phenomenon by drawing the distribution of the 30 sample repeatability index. We then compare the computed and measured repeatability and conclude that our modeling gives good results. We analyse the incidence of weight and workspace location on repeatability and bring additional results to the existing literature.