Fuzzy Adaptive Backstepping Control of Chaotic Roll Motion of Ships Under Input Constraints

Objective To address the risk of progressive capsizing caused by chaotic rolling motion due to parametric excitation in complex sea conditions, and to enhance the safety of navigation. Method Combining backstepping with fuzzy adaptive control, a fuzzy state observer is designed to estimate the unmeasurable roll angular velocity and acceleration in real time. Fuzzy logic systems are introduced to approximate unknown nonlinear functions. An auxiliary control system is constructed to handle the control input issues of the fin stabilizers. Result Simulation experiments indicate that compared with the control methods in existing literature, the Mean Absolute Error (MAE) is reduced by 47.28%, the Mean Integral Absolute value (MIA) is reduced by 17.74%, the Mean Total Variation (MTV) is reduced by 57.20%, and the convergence time is reduced by 44.62%. Conclusion This method can effectively suppress the chaotic rolling motion caused by parametric excitation, significantly enhance the robustness of the control system, reduce the risk of capsizing, and provide a technical guarantee for the safe navigation of ships.