Motion planning and motility maps for flagellar microswimmers.

Area of Science:

• Fluid dynamics
• Microscale robotics
• Non-Newtonian fluid mechanics

Background:

• Microswimmers with elastic tails are crucial for targeted delivery and sensing in microenvironments.
• Previous research focused on sinusoidal actuation, limiting directional control.
• Understanding non-sinusoidal actuation is key to unlocking advanced microswimmer capabilities.

Purpose of the Study:

• To investigate microswimmer propulsion under generic, non-sinusoidal periodic actuations.
• To explore how velocity modulation influences microswimmer motion and directionality.
• To extend previous findings on straight-line propulsion to more complex, controlled movements.

Main Methods:

• Analysis of two microswimmer models: one with a clamped tail, another with a jointed tail.
• Application of an asymptotic perturbation scheme to analyze governing equations.
• Validation of theoretical predictions through numerical simulations and motility maps.

Main Results:

• Non-sinusoidal actuation, specifically velocity modulation, enables directional control.
• Externally actuated swimmers exhibit lateral translation relative to the beating axis.
• Internally actuated swimmers can achieve curved trajectories with velocity-modulated inputs.

Conclusions:

• Velocity modulation is a viable mechanism for controlling microswimmer directionality.
• The study provides explicit formulas and motility maps for predicting microswimmer behavior.
• Findings pave the way for designing microswimmers with enhanced maneuverability.