A Heuristic algorithm for robustly stable generalized disturbance observer synthesis with closed loop consideration.

Area of Science:

• Control Systems Engineering
• Robust Control Theory
• Applied Mathematics

Background:

• Disturbance Observer (DOB) based control is crucial for rejecting external disturbances.
• Traditional DOB methods have limitations in certain control scenarios.
• Enhancing DOB performance requires novel control frameworks.

Purpose of the Study:

• To present a generalized DOB framework for guaranteed closed-loop performance.
• To develop a novel DOB by leveraging Youla factorization.
• To mitigate restrictions of traditional DOB methods.

Main Methods:

• A generalized DOB framework using Youla factorization of a two-degree-of-freedom controller.
• Reconfiguration of Q-filter synthesis into reduced-order controller design.
• A two-stage heuristic algorithm employing Kalman-Yakubovich-Popov (KYP) lemma and projection lemma, involving LMIs.

Main Results:

• The generalized DOB inherits advantages of traditional DOB while overcoming limitations.
• The proposed two-stage algorithm effectively designs reduced-order controllers.
• Demonstrated application to minimum and non-minimum phase plants.

Conclusions:

• The generalized DOB framework offers effective disturbance rejection with guaranteed performance.
• The two-stage heuristic algorithm provides a robust method for controller design.
• The novel DOB approach shows advantages over existing H-infinity based DOB methods.