Comparative Study of Stiffness Modeling Methods for A Novel Industrial Robotic Arm with Hybrid Open-and Closed-Loop Kinematic Chains

Abstract

– Industrial robots are considered as promising options to accomplish machining work due to their advantages of large workspace, good flexibility and low cost. However, industrial robots have weak stiffness and are easy to cause deformations, which affects the machining quality. In this article, a novel industrial robotic arm that has hybrid open-and closed-loop kinematic chains is proposed which is different from the traditional industrial robot. First, the structure of the robot is introduced in brief. Secondly, an analytical method and a semi-analytical method based on strain energy and Castigliano's theorem are proposed to establish the stiffness model of the robot. Finally, the stiffness modeling methods are verified by the FEA and experimental results, and a comparative study of the two stiffness modeling methods is investigated.