Adaptive control improves underwater vehicle tracking under limits
Adaptive Prescribed Performance Trajectory Tracking for Uncertain Autonomous Underwater Vehicles With Input Saturation
Robotics
Summary
Autonomous underwater vehicles need to follow planned paths accurately, but they face challenges like uncertain water forces and limited power from their thrusters. The authors developed a new adaptive control method that automatically adjusts performance goals when the vehicle can't meet strict commands due to thruster limits. They tested it in simulations and real pool experiments, showing it keeps the vehicle on track better than traditional methods. This helps underwater robots operate safely and precisely even with imperfect hardware.
What this means in practice
- •For marine robotics engineers: Maintain stable and accurate underwater vehicle paths despite thruster power limits using the adaptive control method.
- •For industrial automation teams: Implement adaptive controllers to improve path following performance of underwater robots operating in uncertain flow conditions.
Authors
Athanasios K. Gkesoulis, Christos Vlachos, George K. Fourlas, Charalampos P. Bechlioulis, George C. Karras
Abstract
Accurate trajectory tracking is essential for autonomous underwater vehicles operating with uncertain hydrodynamics and limited thruster authority. This paper develops a low-complexity adaptive prescribed performance controller for uncertain underwater vehicle dynamics with coupled and saturated inputs. The proposed method adapts the performance functions directly through the mismatch between the requested and saturated control inputs, enlarging the performance funnels only when the available actuation cannot meet the nominal specifications. A coupled invariant-set analysis establishes boundedness of all closed-loop signals, prescribed bounds on the filtered tracking errors, and explicit feasibility conditions. Comparative simulations on a BlueROV2 underwater vehicle show that the adaptive design maintains prescribed performance during a figure-eight maneuver, whereas conventional prescribed performance control loses feasibility under input limits. A real-time pool experiment further demonstrates stable trajectory tracking and the practical implementation of the proposed method on an underwater robotic platform.