Global Regulation of Feedforward Nonlinear Systems: A Logic-Based Switching Gain Approach

Area of Science:

• Control Theory
• Nonlinear Systems
• Adaptive Control

Background:

• Existing control methods struggle with feedforward nonlinear systems exhibiting unknown input-output-dependent nonlinear growth rates.
• Addressing these uncertainties is crucial for achieving robust global regulation.

Purpose of the Study:

• To develop a novel control strategy for feedforward nonlinear systems with unknown nonlinear growth rates.
• To improve convergence speed and transient performance in global regulation tasks.
• To propose a switching adaptive output feedback (SAOF) controller with low complexity.

Main Methods:

• A logic-based switching (LBS) gain approach is proposed, activating a new gain when Lyapunov function conditions are not met.
• A tanh-type speed-regulation function is integrated into the switching mechanism to enhance performance.
• A switching adaptive output feedback (SAOF) controller is designed based on the LBS mechanism.

Main Results:

• The proposed SAOF controller achieves global regulation for the considered class of nonlinear systems.
• Demonstrated faster convergence speed and superior transient performance compared to existing methods.
• The control approach is extendable to handle external disturbances in feedforward nonlinear systems.

Conclusions:

• The novel LBS gain approach effectively manages system uncertainties and nonlinearities.
• The SAOF controller offers a concise and low-complexity solution for global regulation.
• The enhanced switching mechanism provides a robust framework for controlling nonlinear systems with disturbances.