Reprogrammable Magnetic Soft Robots Based on Low Melting Alloys

Abstract

Magnetic soft robots featuring untethered actuation and high mechanical compliance have promising applications ranging from bionics to biomedicine. However, their fixed magnetization profiles pose a challenge for adaptive shape transformation in unpredictable environments and dynamic tasks. Herein, a reprogrammable magnetic soft composite is reported by encapsulating magnetic neodymium–iron–boron microparticles with low melting alloy (LMA) and embedding them into the elastomer. Utilizing the phase transition of the LMA, the magnetic microparticles can be reoriented under an external magnetic field and they can be immobilized through LMA solidification, allowing the robot to obtain a new magnetization profile corresponding to its temporary shape. By changing the LMA composition, the robot with multiple programming temperatures can be fabricated and its local magnetization profiles can be selectively programmed in different temperature ranges. A bioinspired crawler with multimode locomotion, a reconfigurable robotic gripper capable of adaptable grasping, and reconfigurable electronic circuits are also demonstrated. This work may pave the way for the next‐generation magnetic soft robots and reconfigurable devices.

Principles and methods of liquid metal actuators

“…3D(ii)). 73,77 The driving force, F m , and driving torque, Γ m , acting on such elastomers can be given by 78 F m = μ 0 V ( M r ·∇) H Γ m = μ 0 V ( M r × H )where M r is the remanent magnetization and V is the volume of the magnetic elastomers.…”

Microgripper Robot with End Electropermanent Magnet Collaborative Actuation

“…Xueqi Li et al used cellulose nanofibers through a papermaking process, added sodium alginate and BaFe 12 O 19 particles to synthesize M-films with good foldability, origami, and magnetism, and constructed a multimodal magnetic gripper robot with the functions of programmable movement, grasping and transporting goods, and wireless operation through origami magnetization [ 26 ]. Gangsheng Chen et al constructed a material with multiple programmable temperatures, as the composition of the low-melting alloy (LMA) changes by encapsulating magnetic NdFeB particles with the LMA and embedding them in an elastomer, and the material can be used to fabricate bio-inspired tracks with multimodal motions, reconfigurable robotic grippers capable of adapting to grasping, and reconfigurable electronic circuits [ 27 ]. Zhaoxin Li et al reported a novel multilayer for patterning magnetic nanoparticles in an ultraviolet (UV) cured polymer matrix 3D printing technique, which can be used to achieve shape changes in the robot, including grasping, rolling, swimming, and walking, induced by the global actuation field by programming heterogeneous magnetization within discrete multilayer robotic segments [ 28 ].…”