Robust Output Feedback Stabilization and Tracking for an Uncertain Nonholonomic Systems with Application to a Mobile...

Area of Science:

• Control Systems Engineering
• Robotics
• Nonholonomic Dynamics

Background:

• Underactuated nonholonomic systems present significant control challenges due to limited actuators and velocity constraints.
• Existing control methods often struggle with model uncertainties, external disturbances, and the absence of full state information.

Purpose of the Study:

• To develop a robust output feedback control strategy for simultaneous stabilization and trajectory tracking.
• To address challenges including nontriangular normal forms, non-affine internal dynamics, and non-minimum phase zero dynamics.
• To overcome limitations posed by model uncertainties, external disturbances, and lack of velocity measurements.

Main Methods:

• Input-output feedback linearization and coordinate transformation to achieve a generalized normal form.
• Integration of backstepping and sliding mode control (SMC) techniques.
• Development of a full-order high gain observer (HGO) for state and derivative estimation.

Main Results:

• A novel robust output feedback controller is synthesized by combining HGO and backstepping SMC.
• The proposed controller demonstrates effective stabilization and trajectory tracking for underactuated nonholonomic systems.
• Simulation results validate the controller's robustness against bounded uncertainties, using a differential-drive mobile robot as a case study.

Conclusions:

• The combined backstepping SMC and HGO approach provides a robust solution for controlling complex underactuated nonholonomic systems.
• This method effectively handles system uncertainties and disturbances without requiring velocity measurements.
• The proposed control scheme offers a promising direction for advanced robotics and autonomous systems.