Damping Characteristics in Adaptation of Plastics for Robot Structures

Lightweighting is effective for high-speed operation in industrial robots. One method to achieve this is to use plastics, which are lighter than metallic materials, as structural materials. In addition, structural materials for industrial robots are required to have vibration damping properties. In this study, the damping properties of four types of aluminum alloy and seven types of plastic were investigated using a one-degree-of-freedom experimental machine as a simple model of an industrial robot. The damping ratio was observed to vary with amplitude. Therefore, we propose a variable damping ratio according to the amplitude. Experiments confirmed that this damping ratio can represent better actual phenomena than a constant damping ratio.