Model-Free High-Order Sliding Mode Controller for Station-Keeping of an Autonomous Underwater Vehicle in Manipulation...

Area of Science:

• Robotics
• Ocean Engineering
• Control Systems

Background:

• Autonomous underwater vehicles (AUVs) are increasingly used for inspection, maintenance, and repair missions, requiring precise station-keeping capabilities.
• Existing station-keeping controllers often rely on complex models or observers to handle external disturbances, with limited experimental validation.
• The need for robust, model-free solutions is critical for enhancing AUV operational reliability in dynamic underwater environments.

Purpose of the Study:

• To validate the feasibility of a model-free high-order sliding mode controller for AUV station-keeping.
• To evaluate the controller's performance against unknown external disturbances through both simulations and real-world experiments.
• To demonstrate the controller's robustness and compare its effectiveness against existing methods.

Main Methods:

• Development and implementation of a model-free high-order sliding mode controller.
• Validation through numerical simulations using the BlueROV2 vehicle model.
• Experimental testing in a semi-Olympic swimming pool with introduced, unknown external disturbances.

Main Results:

• Simulations showed the controller achieved outstanding station-keeping, with tracking errors near zero even under simulated strong ocean currents.
• Experimental results demonstrated robust performance, maintaining root mean square error (RMSE) between 1-4 cm for vehicle depth.
• The controller outperformed related work, maintaining effectiveness even when disturbances caused thruster saturation.

Conclusions:

• The proposed model-free high-order sliding mode controller is a feasible and effective solution for AUV station-keeping.
• The controller exhibits significant robustness against unknown external disturbances, crucial for real-world AUV operations.
• This approach offers a promising advancement for AUVs performing complex tasks in challenging underwater conditions.