Distributed global output-feedback formation control without velocity measurement for multiple unmanned surface...

Area of Science:

• Robotics and Control Systems
• Marine Engineering
• Autonomous Systems

Background:

• Formation control of multiple unmanned surface vehicles (USVs) faces challenges due to uncertain dynamics, unmeasurable velocities, and external disturbances.
• Existing methods often struggle with fixed-time convergence and accurate estimation of system states and disturbances.

Purpose of the Study:

• To develop a novel distributed global output-feedback fixed-time formation controller (GOFFC) for multiple USVs.
• To address uncertainties in coefficient matrices, unmeasurable velocities, and time-varying disturbances in USV formation control.
• To ensure fixed-time convergence of the closed-loop system.

Main Methods:

• A global coordinate translation is employed to partially linearize the nonlinear dynamic model, accommodating unmeasurable velocities.
• A fixed-time extended two-state observer (FTETSO) is designed to estimate unmeasurable velocities and total disturbances within a fixed time.
• A sliding mode control technique is integrated with the FTETSO to develop the distributed global output-feedback fixed-time formation controller (GOFFC).

Main Results:

• The proposed FTETSO achieves fixed-time convergence of estimation errors for velocities and disturbances.
• The developed GOFFC ensures fixed-time formation control for multiple USVs under considered uncertainties.
• Simulation results validate the effectiveness and stability of the proposed control approach.

Conclusions:

• The novel FTETSO-based distributed GOFFC effectively solves the formation control problem for USVs with uncertainties.
• The proposed method guarantees fixed-time convergence, enhancing the performance and reliability of USV formations.
• This research contributes a robust control strategy for advanced marine autonomous systems.