Disturbance observer-based delayed robust feedback control design for a class of uncertain variable fractional-order...

Area of Science:

• Control Theory
• Systems Engineering
• Applied Mathematics

Background:

• Variable fractional-order (VFO) neutral-type systems present unique stabilization challenges.
• Structure perturbations and unknown disturbances degrade system performance and stability.
• Existing control methods may not adequately address these complex system dynamics.

Purpose of the Study:

• To develop robust feedback controllers for stabilizing VFO neutral-type systems.
• To design controllers that can effectively handle structure perturbations and unknown disturbances.
• To ensure the robust stability of closed-loop VFO systems under adverse conditions.

Main Methods:

• Design of disturbance-observer-based delayed state- and output-feedback controllers.
• Utilizing a primary controller based on linear feedback and an auxiliary controller with a disturbance observer.
• Formulation of order-dependent and delay-dependent stability conditions using Fractional-Order (FO) Lyapunov theory and matrix inequalities.

Main Results:

• Successful stabilization of VFO neutral-type systems with structure perturbations.
• Effective estimation and compensation of unknown disturbance signals.
• Demonstration of robust stability for the closed-loop system through theoretical conditions and simulations.

Conclusions:

• The proposed disturbance-observer-based delayed feedback control strategy effectively stabilizes VFO neutral-type systems.
• The developed controller ensures robust stability in the presence of structure perturbations and unknown disturbances.
• The theoretical conditions derived from FO Lyapunov theory are validated by simulation results.