Additively manufactured mechanical metamaterial embedded design in robotics for passive vibration attenuation: a proof of concept study

Structural vibrations continue to limit the dynamic performance of industrial robotic arms, while conventional active vibration control techniques often increase complexity, energy consumption, and implementation cost. This study introduces a novel proof of concept approach that embeds additively manufactured mechanical metamaterials (MMs) in a robotic arm to passively attenuate its end-effector vibrations, while maintaining static structural integrity. Focusing on a simplified prototype design of a wire arc additive manufacturing robotic arm, vibration impact hammer testing is performed on individual links, and a validated finite element analysis (FEA) model is developed. FEA dynamic and static stress analyses are then carried out across various operational orientations: full stretch orientation (FSO), half stretch orientation, and least stretch orientation. The robotic arm models were designed with polymer material and analyzed using ANSYS. The impact of varying embedded MM lengths, i.e., 0, 50, 100, and 150 mm, within robotic arm links is analyzed. Based on the experimentally validated FEA model, the harmonic analysis results show that the embedded MM design in robotic arm links expectedly provides superior passive vibration damping, achieving up to a 93% reduction in resonant vibration amplitude in the most structurally vulnerable orientation, i.e., FSO, subjected to 159% higher von Mises stresses. This study highlights the ability of additively manufactured MMs to passively damp robotic arm vibrations without compromising static structural integrity.