Stiffness Measurement and Modeling of Robot Arm Consisting of Single Geared Joint and Link Made of Different Materials

The aim of this study is to establish a lightweight construction method for robot elements using metal and plastic materials in order to achieve energy saving in industrial robots. However, in general, weight reduction reduces stiffness, which in turn reduces the performance required for industrial robots. This paper presents an experimental setup and models to investigate the effects of link stiffness and joint stiffness on overall stiffness, and demonstrates the validity of the models through experiments. Then, experiments with different link materials were conducted and the results were compared. The influence of the fastening method and the fastening torque of the link on the stiffness of the entire system was clarified.