Research on Fault Modeling and Simulation of ROV Electric Propulsion System Based on Modelica

With the growing significance of deep-sea exploration and resource development, underwater vehicles have gained widespread applications across multiple domains, with the propulsion system constituting one of their most critical components. In this study, we investigate fault modeling and simulation techniques for Remotely Operated Vehicle (ROV) electric propulsion systems. Utilizing the Modelica modeling language, we developed a comprehensive mathematical model of the electric thruster coupled with a kinematic model of the underwater vehicle. Through systematic fault injection methodology, three representative fault types were introduced into the system to analyze their respective impacts on system response characteristics. The experimental results demonstrate distinct fault signatures in the system's response curves. Specifically, motor leakage faults were found to inhibit the thruster's ability to achieve commanded speeds, manifesting as fluctuations or time delays in the response curve. Propeller stall conditions were observed to induce substantial imbalances in both resultant forces and moments, consequently causing significant trajectory deviations in ROV operation. Furthermore, inappropriate controller parameter configurations were identified to degrade system performance through reduced response speed and increased overshoot, with the overshoot direction being dependent on the thruster's spatial orientation. These characteristic patterns in response curves provide valuable insights for fault mode identification and precise fault localization, contributing to enhanced system reliability and maintenance efficiency in underwater vehicle operations.