A systematic delayed feedback control approach for unstable periodic orbits in chaotic systems with unknown
Hamed Rezaee1, Eckehard Schöll2, Ludovic Renson3
1School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom.
Chaos (Woodbury, N.Y.)
|December 10, 2025
Summary
This study introduces an adaptive control method for chaotic systems with unknown parameters. The technique stabilizes unstable periodic orbits and guides the system toward natural responses without invasive intervention.
Area of Science:
- Nonlinear Dynamics
- Control Theory
- Chaos Theory
Background:
- Delayed feedback control is common for stabilizing unstable periodic orbits in chaotic systems.
- Existing linear and nonlinear control methods often require system parameter knowledge and lack mechanisms to access natural system responses.
- Unstable periodic orbits are crucial for understanding chaotic system dynamics.
Purpose of the Study:
- To propose a novel adaptive control method for chaotic systems with entirely unknown parameters.
- To achieve stabilization of unstable periodic orbits and convergence to desired periodic responses.
- To develop a controller that steers system dynamics toward natural periodic responses, including unstable periodic orbits.
Main Methods:
- Development of an adaptive control strategy based on delayed system state information.
- Design of a mechanism to guide system dynamics towards natural periodic responses.
- Simulation-based demonstration and application to a Duffing oscillator.
Main Results:
- The proposed control method effectively stabilizes chaotic systems with unknown parameters.
- System states converge to a periodic response with a desired time period.
- The controller successfully steers the system towards natural periodic responses, including unstable periodic orbits, noninvasively.
Conclusions:
- The developed adaptive control strategy offers a noninvasive method for controlling chaotic systems with unknown parameters.
- This approach enables the stabilization of unstable periodic orbits and the exploration of natural system dynamics.
- The method is validated through simulations and its utility in revealing unstable periodic orbits within chaotic attractors is demonstrated.
Related Concept Videos
Time-Domain Interpretation of PD Control
348
Proportional-Derivative (PD) control is a widely used control method in various engineering systems to enhance stability and performance. In a system with only proportional control, common issues include high maximum overshoot and oscillation, observed in both the error signal and its rate of change. This behavior can be divided into three distinct phases: initial overshoot, subsequent undershoot, and gradual stabilization.
Consider the example of control of motor torque. Initially, a positive...
Consider the example of control of motor torque. Initially, a positive...
348
Control System Problem
378
In an open-loop system, such as a basic thermostat, the poles of the transfer function influence the system's response but do not determine its stability. However, when feedback is introduced to form a closed-loop system, such as an advanced thermostat that adjusts heating based on room temperature, stability is governed by the new poles of the closed-loop transfer function.
When forming a closed-loop system, issues can arise if the poles cross into the unstable region, leading to potential...
When forming a closed-loop system, issues can arise if the poles cross into the unstable region, leading to potential...
378
Feedback control systems
657
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...
657
Second Order systems II
369
In an underdamped second-order system, where the damping ratio ζ is between 0 and 1, a unit-step input results in a transfer function that, when transformed using the inverse Laplace method, reveals the output response. The output exhibits a damped sinusoidal oscillation, and the difference between the input and output is termed the error signal. This error signal also demonstrates damped oscillatory behavior. Eventually, as the system reaches a steady state, the error diminishes to zero.
369
Linear Approximation in Time Domain
318
Nonlinear systems often require sophisticated approaches for accurate modeling and analysis, with state-space representation being particularly effective. This method is especially useful for systems where variables and parameters vary with time or operating conditions, such as in a simple pendulum or a translational mechanical system with nonlinear springs.
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...
318
Stability
351
The time response of a linear time-invariant (LTI) system can be divided into transient and steady-state responses. The transient response represents the system's initial reaction to a change in input and diminishes to zero over time. In contrast, the steady-state response is the behavior that persists after the transient effects have faded.
The stability of an LTI system is determined by the roots of its characteristic equation, known as poles. A system is stable if it produces a bounded...
The stability of an LTI system is determined by the roots of its characteristic equation, known as poles. A system is stable if it produces a bounded...
351


