Millirobot Based on a Phase-Transformable Magnetorheological Liquid Metal

Droplet robots have attracted much attention in recent years due to their large-scale deformability and flexible mobility in confined spaces. However, droplet robots are always difficult to maintain rigid shapes, making them difficult to manipulate objects with large inertia. Moreover, their low conductivity makes them unable to complete tasks such as circuit repair. Herein, a millirobot made from magnetorheological liquid metal is proposed to address the problems. Specifically, the magnetorheological liquid metal (MLM) robot is made by engulfing iron particles into gallium–indium alloy, and the mass fraction of the MLM robot is determined by microscopic observation and rheological test. The MLM robot possesses both solid and liquid properties, enabling the robot with plasticity, large-scale deformability, good conductivity, motion flexibility, and good object manipulation. The MLM robot can achieve almost all of the functions of existing droplet robots, including splitting, merging, navigating in narrow channels, and pushing objects. In addition, it can also accomplish some other tasks that are difficult for existing droplet robots, such as pulling large objects, repairing damaged circuits selectively and reversibly, and repairing suspended circuits through plasticity. The demos show that MLM robots can traverse narrow spaces and repair circuit damage selectively and reversibly. It is believed that MLM robots can enrich diverse functionalities in the future.近年来，液滴机器人因其具备大范围形变能力与受限空间内的灵活机动性，受到了广泛关注。然而，液滴机器人难以维持刚性形态，导致其难以操控大惯性物体。此外，其较低的电导率使其无法完成电路修复等相关任务。为此，本文提出一种基于磁流变液态金属的微型机器人，以解决上述问题。具体而言，该磁流变液态金属（magnetorheological liquid metal, MLM）机器人通过将铁颗粒包覆于镓铟合金中制备得到，其质量分数通过显微观测与流变测试确定。该MLM机器人兼具固液两相特性，使其具备可塑性、大范围形变能力、优良导电性、运动灵活性以及出色的物体操控能力。该MLM机器人可实现现有液滴机器人的几乎全部功能，包括分裂、融合、在狭窄通道内导航以及推载物体。此外，其还可完成现有液滴机器人难以实现的多项任务，例如拖拽大质量物体、选择性与可逆地修复受损电路，以及通过可塑性修复悬空电路。演示实验结果表明，MLM机器人可穿行狭窄空间，并实现选择性与可逆的电路损伤修复。可以预见，MLM机器人在未来将进一步丰富机器人的多样化功能。