A MODEL OF TUMBLING TO IMPROVE ROBOT ACCURACY

The main factors that attribute to the accuracy of a direct-drive robo t are the geometry, tumbling joint motion, and encoder errors. This wo rk presents a model that comprises a description of these factors conc entrating on tumbling and encoder errors. The model is based on a new systematic approach to model the geometry. The model is non-redundant and free of singularities. Using the measurements of a single robot ax is all the parameters of the model are identified. Due to the high rep eatability the confidence interval of the found parameters is small. A fter calibration the improved accuracy is very close to the robot's re peatability.