Magnetically actuated mobile microrobots can access distant, enclosed, and small spaces, such as inside microfluidic channels and the human body, making them appealing for minimally invasive tasks. Despite their simplicity when scaling down, creating collective microrobots that can work closely and cooperatively, as well as reconfigure their formations for different tasks, would significantly enhance their capabilities such as manipulation of objects. However, a challenge of realizing such cooperative magnetic microrobots is to program and reconfigure their formations and collective motions with under-actuated control signals. This article presents a method of controlling 2D static and time-varying formations among collective self-repelling ferromagnetic microrobots (100 μ m to 350 μ m in diameter, up to 260 in number) by spatially and temporally programming an external magnetic potential energy distribution at the air–water interface or on solid surfaces. A general design method is introduced to program external magnetic potential energy using ferromagnets. A predictive model of the collective system is also presented to predict the formation and guide the design procedure. With the proposed method, versatile complex static formations are experimentally demonstrated and the programmability and scaling effects of formations are analyzed. We also demonstrate the collective mobility of these magnetic microrobots by controlling them to exhibit bio-inspired collective behaviors such as aggregation, directional motion with arbitrary swarm headings, and rotational swarming motion. Finally, the functions of the produced microrobotic swarm are demonstrated by controlling them to navigate through cluttered environments and complete reconfigurable cooperative manipulation tasks.

中文翻译：

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控制磁性微型机器人群的二维集体形成和协作行为

磁力驱动的移动微型机器人可以进入远处、封闭和狭小的空间，例如微流体通道内部和人体，使它们对微创任务具有吸引力。尽管它们在缩小时很简单，但创建可以密切合作的集体微型机器人，以及为不同的任务重新配置它们的编队，将显着增强它们的能力，例如操纵物体。然而，实现这种协作磁性微型机器人的一个挑战是使用欠驱动控制信号来编程和重新配置它们的编队和集体运动。本文介绍了一种控制集体自排斥铁磁微型机器人（直径为 100 μm 至 350 μm，多达 260 个）通过空间和时间编程空气-水界面或固体表面上的外部磁势能分布。介绍了使用铁磁体对外部磁势能进行编程的通用设计方法。还提出了集体系统的预测模型，以预测形成并指导设计程序。使用所提出的方法，通过实验证明了通用的复杂静态地层，并分析了地层的可编程性和缩放效应。我们还通过控制这些磁性微型机器人表现出受生物启发的集体行为来展示这些磁性微型机器人的集体移动性，例如聚集、具有任意群方向的定向运动和旋转蜂群运动。最后，