Stiffness evaluation of a metalforming industrial robot

This paper proposes a Cartesian stiffness matrix evaluation method for 6DOF industrial robots. First, the tool center point (TCP) deviation as result of the low stiffness of robots is analysed. For different metalforming areas, the low stiffness conducts to common defects on the quality product, such defects and their relations are studied. A model-based solution for the Cartesian stiffness matrix and a joint compliance evaluating method are proposed. A Fanuc 200IC industrial serial robot and Matlab software are used for the experimental procedure. Finally, the joint stiffness results agreed well to the TCP orientations corresponding to 1 mm deviation for an extended robot pose. Future works will focus on the external load application system in order to characterize the stiffness map using a complete wrench vector.