Enhanced extended state observer-based control for systems with mismatched uncertainties and disturbances

Area of Science:

• Control Systems Engineering
• Non-linear System Analysis
• Observer-Based Control

Background:

• Extended State Observer (ESO) is a powerful tool for disturbance estimation and rejection.
• Conventional ESO is primarily designed for systems in integral-chain form with matched uncertainties.
• Existing methods face limitations when dealing with non-integral-chain systems and mismatched uncertainties.

Purpose of the Study:

• To develop an enhanced Extended State Observer (ESO)-based control strategy for non-integral-chain systems.
• To address disturbance attenuation in the presence of non-linear mismatched uncertainties and external disturbances.
• To extend the applicability of ESO principles to a wider class of complex systems.

Main Methods:

• Design of a novel control strategy combining state-feedback with a dynamic disturbance compensation term.
• The proposed strategy does not require the system to be in integral-chain form.
• Theoretical analysis of internal zero-dynamics and closed-loop stability for the proposed control.

Main Results:

• The enhanced ESO strategy effectively attenuates disturbances and compensates for non-linear mismatched uncertainties.
• The proposed method reduces to the conventional ESO under standard integral-chain and matched conditions.
• Numerical simulations demonstrate superior performance compared to existing ESO-based techniques.

Conclusions:

• The enhanced ESO-based control strategy offers a significant advancement for disturbance attenuation in non-integral-chain systems.
• The internal zero-dynamics is crucial for the successful design of ESO-based controllers.
• The proposed approach provides a robust and effective solution for complex control problems.