Related Experiment Video
Updated: Jan 18, 2026

The Modular Design and Production of an Intelligent Robot Based on a Closed-Loop Control Strategy
Published on: October 14, 2017
Optimal Closed-Loop Control of Active Particles and a Minimal Information Engine
Rosalba Garcia-Millan1,2,3, Janik Schüttler2, Michael E Cates2
1King's College London, Department of Mathematics, London WC2R 2LS, United Kingdom.
This study reveals that optimal protocols for moving active particles are unaffected by activity itself, though work fluctuations increase. A novel active information engine demonstrates superior precision and efficiency with run-and-tumble particles.
Area of Science:
- Statistical mechanics
- Active matter physics
- Thermodynamics of information
Background:
- Active particles consume energy to generate motion, deviating from equilibrium thermodynamics.
- Understanding work input and fluctuations is crucial for designing micro-machines.
Purpose of the Study:
- To determine optimal protocols for minimum work input when moving active particles.
- To analyze the impact of particle activity on work and fluctuations.
- To design and evaluate an active information engine.
Main Methods:
- Analytical derivation of optimal protocols for open-loop and closed-loop systems.
- Investigation of work input and fluctuations for different particle types.
- Derivation and analysis of a periodic active information engine.
Main Results:
- Open-loop optimal protocols are independent of particle activity, but increase work fluctuations.
- Closed-loop protocols show minimum average work for finite persistence times.
- The run-and-tumble particle yields higher precision and information efficiency in the active information engine.
Conclusions:
- Activity influences work fluctuations but not the fundamental open-loop optimal path.
- Closed-loop control offers advantages by utilizing initial measurements.
- The run-and-tumble model provides a highly efficient active information engine.
Related Concept Videos
Open and closed-loop control systems
An open-loop control system operates without feedback from the output. It consists of two primary elements: the controller and the controlled process. The controller receives an input signal...
Control Systems
At the heart...
Conservation of Energy in Control Volume
For steady flow systems, the time derivative of the stored energy becomes zero since there is no energy accumulation within the control volume. This simplifies the energy equation to:
Feedback control systems
Linear feedback systems are theoretical models that simplify analysis and design. These systems operate under the principle that their output is directly proportional to their input within certain ranges. For instance, an amplifier in a control system behaves linearly as long as the input signal remains within a specific range. However, most physical systems exhibit inherent nonlinearity...
Catalytically Perfect Enzymes
Most enzymes...
Equilibrium Conditions for a Particle
To understand the concept of equilibrium, let us first consider the forces acting on an object. When different forces act on an object, they can...

