Untethered miniature robots have significant potential and promise in diverse minimally invasive medical applications inside the human body. For drug delivery and physical contraception applications inside tubular structures, it is desirable to have a miniature anchoring robot with self-locking mechanism at a target tubular region. Moreover, the behavior of this robot should be tracked and feedback-controlled by a medical imaging-based system. While such a system is unavailable, we report a reversible untethered anchoring robot design based on remote magnetic actuation. The current robot prototype's dimension is 7.5 mm in diameter, 17.8 mm in length, and made of soft polyurethane elastomer, photopolymer, and two tiny permanent magnets. Its relaxation and anchoring states can be maintained in a stable manner without supplying any control and actuation input. To control the robot's locomotion, we implement a two-dimensional (2D) ultrasound imaging-based tracking and control system, which automatically sweeps locally and updates the robot's position. With such a system, we demonstrate that the robot can be controlled to follow a pre-defined 1D path with the maximal position error of 0.53 $\boldsymbol{\pm }$ 0.05 mm inside a tubular phantom, where the reversible anchoring could be achieved under the monitoring of ultrasound imaging.

中文翻译：

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超声引导无线管状机器人锚固系统

不受束缚的微型机器人在人体内部的各种微创医疗应用中具有巨大的潜力和前景。对于管状结构内的药物输送和物理避孕应用，需要在目标管状区域具有具有自锁机制的微型锚定机器人。此外，该机器人的行为应由基于医学成像的系统进行跟踪和反馈控制。虽然这样的系统不可用，但我们报告了一种基于远程磁驱动的可逆无绳锚定机器人设计。当前机器人原型的尺寸为直径 7.5 毫米，长度 17.8 毫米，由软质聚氨酯弹性体、光敏聚合物和两个微型永磁体制成。它的松弛和锚定状态可以以稳定的方式保持，而无需提供任何控制和驱动输入。为了控制机器人的运动，我们实现了一个基于二维 (2D) 超声成像的跟踪和控制系统，该系统会自动局部扫描并更新机器人的位置。有了这样的系统，我们证明了机器人可以被控制以遵循预先定义的一维路径，在管状体模内的最大位置误差为 0.53 $\boldsymbol{\pm }$ 0.05 mm，可以实现可逆锚定在超声成像监测下。