Common digestive and lung disorders such as stomach problems and pleural emission pose serious difficulties for patients who undergo open surgeries wherein a wirelessly powered swimming microrobot has the potential for minimally invasive missions from diagnosis to drug delivery and surgery. However, remote steering toward an arbitrary destination is yet a challenge to existing microrobots. Here, a resonant wireless power transfer system is incorporated into an array of planar coils to generate spatio-temporal patterns of magnetic fields on an untethered swimming microrobot. As shown, this generates an effective Lorentz force on the microrobot's power receptor coil. Automated switching of the array current creates a traveling magnetic pattern that enables smooth microrobot steering and controls its velocity. This eliminates the need for embedded magnets and shielding materials that suffer from nonlinear characteristics. The microrobot's function is validated by an in vitro experiment that mimics the anatomy of the stomach filled with fluid at a centimeter range underneath the skin. Our microrobot with a mass of 7 g is able to reach the velocity of 0.45 mm/s in a controlled direction by applying a small peak magnetic field of 2.15 mT at 96 kHz. The propelling force is proportional to the square of the total magnetic field's intensity and can be enormously increased depending on the application. Compared to microrobots with similar dimensions, this method results in a 50-fold increased ratio of propelling force to applied magnetic energy, which is suitable for carrying heavier payloads to farther locations.

中文翻译：

---

图案化的磁场，用于向游泳微型机器人进行遥控和无线供电

常见的消化系统和肺部疾病（例如胃部问题和胸膜排出物）对接受开放手术的患者造成严重困难，其中无线游泳微型机器人具有从诊断到给药和手术的微创任务的潜力。然而，向任意目的地的远程操纵仍然是现有微型机器人的挑战。在此，将谐振无线电力传输系统并入平面线圈阵列中，以在无系绳游泳微型机器人上产生磁场的时空模式。如图所示，这会在微型机器人的功率接收器线圈上产生有效的洛伦兹力。阵列电流的自动切换会产生行进的磁模式，从而使微型机器人转向平稳并控制其速度。这消除了对具有非线性特性的嵌入式磁体和屏蔽材料的需求。微型机器人的功能通过一项体外实验得以验证，该实验模仿了在皮肤下一厘米范围内充满液体的胃部解剖结构。我们的微型机器人质量为7 g，通过在96 kHz处施加2.15 mT的小峰值磁场，可以在受控方向上达到0.45 mm / s的速度。推进力与总磁场强度的平方成正比，可以根据应用极大地增加。与具有类似尺寸的微型机器人相比，此方法可将推进力与施加的磁能之比提高50倍，适用于将较重的有效载荷运送到更远的位置。