Analysis of thruster degradation effects on the posture control of a remotely operated vehicle

Abstract This paper presents an analysis of mobility on an over-actuated Remotely Operated Vehicle (ROV) that becomes under-actuated due to multiple actuator faults of different types of degradation. The analysis is developed on a regulation control problem, including modeling and robust control design. The dynamic model is formulated using a Port-Hamiltonian formalism, emphasizing energy conservation and passivity. The control strategy is developed through a Control by Interconnection (CbI) structure to regulate the ROV posture as an interconnected energy-based system. Singular Value Decomposition (SVD) is employed to assess mobility effectiveness in each spatial direction. Quadratic Programming (QP) is used for realistic control allocation under actuator constraints and fault conditions, highlighting the direction with reduced effectiveness for improving performance in a complete posture regulation task. The simulation results validate control allocation based on QP, demonstrating its robustness in maintaining ROV stability and achieving posture regulation under various fault scenarios. It has been shown that the ROV topology under study supports two individual thruster faults and still achieves a 3D target, and the resulting reduced directions can be enhanced by QP allocation; for instance, yaw error is improved by nearly 50% compared with the SVD method, demonstrating its ability to redistribute control forces efficiently while preserving closed-loop stability. Furthermore, computational performance analysis confirms the approach’s real-time feasibility for experimental implementation, with the QP solver operating at about 1 ms per iteration.