Active disturbance rejection control for non-minimum phase systems under plant reconstruction

Area of Science:

• Control Systems Engineering
• Non-linear Dynamics
• Robotics

Background:

• Active Disturbance Rejection Control (ADRC) is challenging for non-minimum phase (NMP) systems due to stability and tuning conflicts.
• Enhancing robustness in NMP systems typically requires extensive feedback tuning, which can be problematic.

Purpose of the Study:

• To develop a novel ADRC scheme for NMP systems that avoids heavy feedback tuning.
• To improve the robustness and stability of ADRC in NMP systems through plant reconstruction and cascade compensation.

Main Methods:

• Plant reconstruction to explicitly identify internal disturbances.
• Development of a new ADRC scheme integrating plant reconstruction and cascade compensation.
• Derivation of internal stability criteria for the proposed ADRC system.

Main Results:

• The proposed ADRC scheme effectively reduces internal disturbances via cascade compensation.
• Derived stability conditions offer design guidance for compensators and disturbance observers.
• Demonstrated that cascade compensation enhances the robust stability of NMP systems.

Conclusions:

• The novel ADRC scheme based on plant reconstruction is effective for NMP systems.
• The method provides a pathway to robust control without excessive feedback tuning.
• Experimental validation on a motion NMP system confirms the physical realizability and efficacy.