Uncertainty of the virtual geometric measurements in the automotive industry

The Virtual Measurement Data Analysis (VMDA) is a system developed at Volkswagen AG, which is applied to analyze the geometrical features of the vehicle. The basis of the VMDA is a combination of the virtual vehicle model with the real measurement data. The virtual measurements of gaps between parts or assemblies are indirect measurements given as an algorithm. An approach for the evaluation of the uncertainty of the virtual geometric measurements was proposed and the propagation of the measurement uncertainty in the virtual vehicle analyzed. An analysis of the measurement uncertainty propagation was carried out: from the measurement uncertainty of point coordinates to the combined uncertainty of the virtual measurements of gaps. Significant correlation effects on the combined uncertainty of the virtual gap measurement were shown.