DETERMINATION OF STRAIGHTNESS ERRORS IN A WELDING ROBOT

摘要

In some large industries, a robotic arm describing predefined paths in work volume and carrying a welding gun executes automatic welding operations. The deviations in relation to ideal robot arm predefined paths may cause severe distortions in welded parts. The displacement along a straight path must be close to the ideal straight line and the deviations cause a poor quality weld. In this case, the straightness errors in two orthogonal planes crossing the planned welding line can be considered as parameters to predict welding quality. In this work, an approach was used to investigate the performance of a welding cell that requires the determination of path straightness of a robot arm movement using online programming. This approach involves the use of a dial gauge connected to the robot arm and moved over a reference straight standard. The straightness was determined as the range of the measurement errors at each measuring line and was determined in several different locations in work volume. The results obtained showed that the different regions in work volume promote the change in weld quality and error compensation may be applied to improve the accuracy in welding operations.