Origami-Inspired Variable Stiffness Actuator for Safe Human–Robot Interaction

Abstract

Abstract In this paper, an origami-inspired variable stiffness actuator (OVSA) is proposed. Innovatively borrowing from the origami principle, OVSA uses torsion springs and hinges to form a transformable hexagonal structure as the special elastic component. While having a light and compact structure, it can also theoretically realize the change of stiffness from zero to infinity. Archimedean Spiral Cam (ASC) is used as a transmission element to connect the motor and elastic components further increasing the compactness of the structure. In addition, the OVSA requires very little torque to maintain stiffness under deflection conditions, which improves energy efficiency. In this paper, the stiffness equation of OVSA is established and verified by experiments. The results show that its stiffness is high when the deflection angle is close to 0 deg and decreases rapidly with the increase of deflection angle, which makes it have sufficient safety.