High Precision Modeling for a Multi-Axis Robot Considering Interference Force based on Robot Dynamic Model

This paper presents a high precision modeling approach for a multi-axis robot considering interference force between axes based on a dynamic model of a multi-axis robot. It is well-known that interference force affects positioning performance especially in high speed positioning motion. In order to overcome the problem, it needs a high precision model which can reproduce actual motion of a multi-axis robot. In this paper, a combined modeling approach which consists of a two-mass model and a dynamic model is proposed, where each axis is basically modeled as a two-mass model to reproduce mechanical vibrations due to elastic mechanism of the reduction gear. Interference force between axes is theoretically modeled based on a dynamic model of a multi-axis robot. The inertial term of interference force is added as disturbance at motor-side, while the velocity term of interference force and gravity force are added as disturbance at load-side. The effectiveness of the proposed modeling approach has been verified based on a comparative study with a conventional model approach based on a two-mass model only.