Related Experiment Video
Updated: Apr 23, 2026

10:13
A Microfluidic-based Hydrodynamic Trap for Single Particles
Published on: January 21, 2011
16.0K
Real-time calibration of a feedback trap
Momčilo Gavrilov1, Yonggun Jun1, John Bechhoefer1
1Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
The Review of Scientific Instruments
|October 3, 2014
Summary
A new recursive maximum likelihood (RML) algorithm enables precise, long-term control of electric forces in feedback traps. This overcomes drift issues, allowing hours of stable particle manipulation for advanced physics research.
Area of Science:
- Physics
- Physical Chemistry
- Statistical Mechanics
Background:
- Feedback traps utilize closed-loop control for manipulating particles and molecules in solution.
- Applications in measuring particle properties and non-equilibrium statistical mechanics are limited by electric force drifts over time.
Purpose of the Study:
- To develop a method for real-time measurement and control of electric and stochastic forces in feedback traps over extended durations (hours).
- To overcome limitations imposed by electric force drifts in particle manipulation experiments.
Main Methods:
- Implementation of a recursive maximum likelihood (RML) algorithm for real-time data analysis and feedback control.
- Simulations to validate the RML algorithm's accuracy in parameter recovery.
- Experimental application to measure diffusion coefficients of particles.
Main Results:
- The RML algorithm demonstrated the ability to perform real-time measurement and control of forces over hours.
- Simulations confirmed accurate recovery of known parameters by the RML algorithm.
- Experimental diffusion coefficient estimates aligned with expected physical properties.
Conclusions:
- The RML algorithm significantly enhances the stability and duration of feedback trap experiments.
- This advancement enables more robust measurements and exploration of non-equilibrium systems.
- The RML algorithm provides a powerful tool for precise manipulation and characterization of small systems.
Related Concept Videos
Effects of feedback
1.1K
Feedback in control systems plays a critical role in shaping various operational parameters, extending beyond simple error reduction to influence stability, bandwidth, gain, impedance, and sensitivity. Understanding these effects requires examining a basic feedback system characterized by defined input, output, error, and feedback signals.
Feedback significantly modifies the gain of a control system. The gain of a system without feedback is altered by a factor of one plus GH, where G represents...
Feedback significantly modifies the gain of a control system. The gain of a system without feedback is altered by a factor of one plus GH, where G represents...
1.1K
Feedback control systems
792
Feedback control systems are categorized in various ways based on their design, analysis, and signal types.
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...
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...
792
Feedback Loops
43.3K
In most cases, excessive hormone production is prevented by negative feedback—a loop that starts with a stimulus inducing the release of a particular substance, like a hormone, to maintain a certain level before triggering a signal that results in a decrease in further release of the hormone.
43.3K
Time and frequency -Domain Interpretation of PI Control
499
Proportional-Integral (PI) controllers are essential in many control systems to improve stability and performance. They are commonly used in everyday devices like thermostats to enhance system damping and reduce steady-state error. When the zero in the controller's transfer function is optimally placed, the system benefits significantly in terms of stability and accuracy.
Acting as a low-pass filter, the PI controller slows the system's response and extends settling times. This requires...
Acting as a low-pass filter, the PI controller slows the system's response and extends settling times. This requires...
499
Positive and Negative Feedback Loops
14.8K
Animal organs and organ systems constantly adjust to internal and external changes through a process called homeostasis ("steady state"). Examples of these changes include regulation of the level of glucose or calcium in the blood or internal responses to external temperatures. Homeostasis requires maintaining an internal dynamic equilibrium:
14.8K
Control Systems
1.6K
Control systems are everywhere in contemporary society, influencing diverse applications from aerospace to automated manufacturing. These systems can be found naturally within biological processes, such as blood sugar regulation and heart rate adjustment in response to stress, as well as in man-made systems like elevators and automated vehicles. A control system is essentially a network of subsystems and processes that collaboratively convert specific inputs into desired outputs.
At the heart...
At the heart...
1.6K

