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Updated: Aug 6, 2026
09:22
Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)
Published on: October 31, 2011
Accuracy comes at a cost: Optimal localization against a flow
Till Welker1, Patrick Pietzonka1
1University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh, United Kingdom.
Physical Review. E
|July 24, 2026
Summary
Controlling propelled particles near a target requires active driving, balancing accuracy and energetic cost. Optimal strategies involve switching between passive and active states, with time-dependent diffusivity enhancing control.
Area of Science:
- Physics
- Statistical Mechanics
- Soft Matter Physics
Background:
- Particles in noisy environments face challenges like thermal fluctuations and fluid flow.
- Maintaining particle localization near a target requires active control strategies.
Purpose of the Study:
- To determine the energetic cost of controlling a propelled particle near a target.
- To find optimal time-dependent protocols for swim velocity and diffusivity without feedback.
- To establish a tradeoff between accuracy and energetic cost.
Main Methods:
- Investigated finite-time control protocols for a propelled particle.
- Analyzed time-dependent swim velocity and diffusivity.
- Quantified accuracy using mean squared deviation.
Main Results:
- A tradeoff exists between particle localization accuracy and energetic cost.
- Achieving high accuracy necessitates active driving with increasing cost.
- Optimal protocols feature discontinuous switching between passive and active propulsion states.
- Time-dependent diffusivity improves control and accuracy.
Conclusions:
- Active control is essential for precise particle localization against noise and flow.
- Optimal control strategies can involve discontinuous changes in particle dynamics.
- This work provides benchmarks for artificial self-propelled particles in complex environments.
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