Active Disturbance Rejection Control of Euler-Lagrange Systems Exploiting Internal Damping.

Area of Science:

• Control Theory
• Robotics
• Mechanical Engineering

Background:

• Traditional Active Disturbance Rejection Control (ADRC) forces system dynamics into a double-integral form, often neglecting physical structures.
• The Extended State Observer (ESO) is a key component in ADRC for estimating and rejecting disturbances.
• Existing ADRC designs may not fully leverage inherent system properties like internal damping.

Purpose of the Study:

• To propose a novel ADRC framework that fundamentally incorporates the physical structure of Euler-Lagrange (EL) systems.
• To enable significantly smaller or zero differential feedback gains by exploiting system's internal damping.
• To develop a physically interpretable and practically significant control design.

Main Methods:

• Incorporation of Euler-Lagrange system dynamics into the ADRC framework.
• Analysis of energy balance in EL systems to derive a physically meaningful design principle.
• Design of a sliding-mode Extended State Observer (ESO) for enhanced estimation.
• Application to tracking control of an omnidirectional mobile robot.

Main Results:

• A new ADRC framework is presented that leverages the physical structure of EL systems.
• Effective utilization of internal damping allows for reduced differential feedback gains.
• The sliding-mode ESO demonstrates improved estimation performance compared to linear ESOs.
• Experimental validation on an omnidirectional mobile robot confirms the proposed design's efficacy.

Conclusions:

• The proposed ADRC framework offers a physically grounded approach to control design for EL systems.
• Exploiting internal damping provides practical advantages and simplifies controller design.
• The integration of a sliding-mode ESO enhances disturbance estimation and rejection capabilities.
• The framework is experimentally verified, showing its practical applicability in robotics.