Constrained control using novel nonlinear mapping for underactuated unmanned surface vehicles with unknown sideslip...

Area of Science:

• Robotics
• Control Systems Engineering
• Marine Engineering

Background:

• Underactuated Unmanned Surface Vehicles (USVs) face challenges in path following due to state constraints and input saturation.
• Accurate trajectory tracking is crucial for USV operations, but is complicated by factors like unknown sideslip angles and cross-tracking errors.

Purpose of the Study:

• To develop a robust guidance and control strategy for underactuated USVs to follow parameterized curved paths.
• To address limitations imposed by state constraints, input saturation, unknown sideslip angles, and cross-tracking error constraints.

Main Methods:

• A novel line-of-sight (LOS) guidance law incorporating sideslip angle compensation was designed.
• A nonlinear mapping (NM) function was introduced to transform constrained subsystems into unconstrained ones.
• Adaptive fuzzy control laws were developed to manage unknown disturbances and input saturation.
• Input-to-state stability theories were employed for theoretical analysis.

Main Results:

• The proposed guidance law effectively guides the USV to the desired path within specified error bounds.
• The nonlinear mapping successfully converted the constrained control problem into an unconstrained one.
• Adaptive fuzzy control achieved the desired path-following objectives despite system uncertainties and saturation.
• Theoretical analysis confirmed the boundedness of tracking errors.

Conclusions:

• The developed guidance and control algorithms demonstrate effectiveness for underactuated USVs in complex path-following scenarios.
• The approach offers a robust solution for USVs operating with state constraints and input saturation.
• Numerical simulations validated the practical applicability and performance of the proposed methods.