Influence of vision measurement system spatial configuration on measurement uncertainty, based on the example of electric traction application

Technical diagnostics plays a significant role in ensuring operational reliability of electrified rail transport. The most critical point in the transmission of electric energy to vehicles is the sliding contact of the current collector with the traction network. For this reason, work is currently being carried on new measuring methods, whose appliance allows for more complete diagnostics of the contact line and current collectors, as well as for monitoring the co-operation of these elements. Each measurement method must be analysed for level of uncertainty, so that the obtained measurement results are reliable. This paper presents a theoretical analysis of the influence of the visual measuring method spatial configuration on the obtained level of measurement uncertainty. This method is designed for measurement contact wire displacements. The results of theoretical analysis were verified by a measurement experiment performed with the use of the Last Square Fitting Algorithm. Finally, the results of sample measurement results obtained at the laboratory tests stand, which proved the practical usefulness of the discussed measurement method, were presented.