Wireless robots at the subcentimeter size are often actuated using externally generated magnetic fields. For most applications, these remote magnetic microrobots are located relatively far from the magnetic field generation sources. In this condition, all microrobots receive approximately the same driving magnetic field (which we term a homogeneous field). While some solutions have been presented to allow for the creation of simple onboard tools, the full potential of the homogeneous magnetic field for multi-degrees-of-freedom (DOF) actuation has not been exploited. Here we introduce a design framework to utilize the maximum number of independently controlled DOFs on a microrobot system. We make use of three classes of mechanisms which are commonly used in practice and allow for more complex microrobots with up to eight DOFs. To verify the functionality of our framework, we used it to design an optimized drug delivery robot equipped with a 3-DOF drug-releasing mechanism and a 4-DOF motion mechanism. Experiments are performed to actuate each one of the robot’s seven DOFs individually, where the cross-talk error between these seven DOFs averaged 7 $\%$ with a max error of 18.3%.

中文翻译：

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均匀准静态磁场驱动的多自由度微型机器人设计

亚厘米大小的无线机器人通常使用外部产生的磁场来驱动。对于大多数应用，这些远程磁性微型机器人距离磁场产生源相对较远。在这种情况下，所有微型机器人都会接收到大致相同的驱动磁场（我们称之为均匀场）。虽然已经提出了一些解决方案来允许创建简单的机载工具，但尚未利用均匀磁场的多自由度 (DOF) 驱动的全部潜力。在这里，我们介绍了一个设计框架，以在微型机器人系统上利用最大数量的独立控制自由度。我们利用实践中常用的三类机制，并允许具有多达八个自由度的更复杂的微型机器人。为了验证我们框架的功能，我们使用它来设计一个优化的给药机器人，配备了一个 3-DOF 药物释放机构和一个 4-DOF 运动机构。进行实验以单独驱动机器人的七个自由度中的每一个，其中这七个自由度之间的串扰误差平均为 7 $\%$，最大误差为 18.3%。