A magneto-elastica reinforced elastomer makes soft robotic grippers

Abstract

Soft robotics represents a burgeoning and interdisciplinary domain characterized by diverse research avenues encompassing actuation strategies, materials science, fabrication techniques, morphing mechanisms, and control methods. This work introduces a novel approach to soft actuators and robotic grippers by intricately exploring the magneto-elastica of spherical magnet chains. First, a kind of magneto-elastica reinforced elastomer is achieved by embedding millimetre-sized spherical neodymium-iron-boron (NdFeB) magnets into the polymer elastomer. By modulating the coupling effect of the magnetic and elastic contributions, the bending deformation of the magneto-elastica reinforced elastomer can be initialized. Subsequently, we analytically derive the coupled stiffness formula to integrate the discrete-scale magneto-elastica with the continuum elasticity using the transformed section method. For comparison, we further employ the multi-physics coupling simulation method to reveal the complex magnetics-mechanics interactions within the composite beam. As a proof of concept, we demonstrate two distinct configurations of rope-motor-driven robotic grippers respectively: three-finger soft robotic gripper and five-finger soft anthropomorphic hand. Pick-and-place experiments indicate that they have the good applicability to grasp objects with various sizes, surfaces and forms, including delicate, deformable, and irregularly shaped objects. In conclusion, the proposed method offers compelling advantages, including structural simplicity and modularity, facile manufacturability utilizing commonplace materials and 3D printing, in-situ active magneto-elastica-driven resilience and selectable actuation modalities via either magnetic or mechanical stimuli. We anticipate that the exploratory research can potentially manifest further contributions to soft actuators and soft robots.