Feedback control of three-bead achiral robotic microswimmers

In this paper, we demonstrate the feedback control of the three-bead achiral microswimmers in simulation and experiment. The achiral microswimmers are controlled wirelessly using magnetic fields with the ability to swim in bulk fluid. The achirality of the microswimmer introduces unknown handedness of the microswimmer resulting in uncertainty in swimming direction. We use a combination of rotating and static magnetic fields generated from an approximate Helmholtz coil system to overcome such uncertainty. We estimate a quantitative kinematic model based on data fitting of experimental data and design the vision-based feedback control for the microswimmers using the estimated kinematic model. Through simulation and experiments, we show that the feedback control law can move an achiral microswimmer from any initial conditions to a target pose.