The Rotation of Microrobot Simplifies 3D Control Inside Microchannels

Area of Science:

• Biomedical Engineering
• Microfluidics
• Robotics

Background:

• Controlling microrobots in microchannels is challenging due to complex fluid dynamics.
• Helical microrobots offer unique propulsion but require precise steering mechanisms.

Purpose of the Study:

• To investigate the wall-induced orbiting phenomenon of helical microrobots in microchannels.
• To demonstrate how this phenomenon simplifies microrobot control for navigation.
• To explore the potential for 3D control using 2D feedback systems.

Main Methods:

• Experimental validation using 50 μm long, 5 μm diameter helical microrobots.
• Numerical simulations to analyze microrobot dynamics and control implications.
• Utilizing standard 2D microscopy for feedback and control.

Main Results:

• Proved that proximity to channel walls generates a perpendicular force, causing microrobots to orbit the channel centerline.
• Demonstrated simplified control, enabling navigation even with imperfect propulsion alignment.
• Showed that 3D microrobot centering in in-plane channels is achievable by controlling only the yaw angle.
• Confirmed that 3D channel following is possible with 2D feedback for both yaw and pitch control.

Conclusions:

• The wall-induced orbiting phenomenon significantly simplifies microrobot control in microchannels.
• Standard 2D microscopy is sufficient for precise 3D navigation of helical microrobots.
• This control simplification paves the way for advanced imaging and potential in vivo applications.