Laboratoire de Photonique et de Nanostructure, Centre National de la Recherche Scientifique, Marcoussis, 91460, France.
Sci Rep. 2018 Jan 11;8(1):438. doi: 10.1038/s41598-017-18891-w.
This paper focuses on the control of rotating helical microrobots inside microchannels. We first use a 50 μm long and 5 μm in diameter helical robot to prove that the proximity of the channel walls create a perpendicular force on the robot. This force makes the robot orbit around the channel center line. We also demonstrate experimentally that this phenomenon simplifies the robot control by guiding it on a channel even if the robot propulsion is not perfectly aligned with the channel direction. We then use numerical simulations, validated by real experimental cases, to show different implications on the microrobot control of this orbiting phenomenon. First, the robot can be centered in 3D inside an in-plane microchannel only by controlling its horizontal direction (yaw angle). This means that a rotating microrobot can be precisely controlled along the center of a microfluidic channel only by using a standard 2D microscopy technology. Second, the robot horizontal (yaw) and vertical (pitch) directions can be controlled to follow a 3D evolving channel only with a 2D feedback. We believe this could lead to simplify imaging systems for the potential in vivo integration of such microrobots.
本文专注于控制旋转螺旋微型机器人在微通道内的运动。我们首先使用一个 50 微米长、5 微米直径的螺旋机器人来证明通道壁的接近会在机器人上产生一个垂直于机器人的力。这个力使机器人围绕通道中心线旋转。我们还通过实验证明，即使机器人的推进力不完全与通道方向对齐，这种现象也可以简化机器人的控制，从而引导机器人在通道上运动。然后，我们使用数值模拟，结合真实实验案例，展示了这种轨道现象对微机器人控制的不同影响。首先，机器人可以在平面内的微通道中仅通过控制其水平方向（偏航角）而在 3D 空间中居中。这意味着，通过使用标准的二维显微镜技术，旋转的微型机器人可以精确地沿着微流控通道的中心进行控制。其次，机器人的水平（偏航）和垂直（俯仰）方向可以通过二维反馈来控制，以跟随 3D 不断变化的通道。我们相信，这可能会简化成像系统，为这种微型机器人的潜在体内集成提供便利。
