Dynamical Analysis and Chaos Control of Yaw Motion for Very Large Ships in Regular Longitudinal Waves

For the purpose of interpreting and controlling the irregular yaw motion of very large ships in waves, both analytical and numerical methods are employed in this study. A nonlinear dynamic model considering the behaviors of the human navigator for the yawing system of the ships in regular longitudinal waves is constructed and analyzed based on the bifurcation and chaos theory. The results of analysis indicate the existence of chaotic regions for the system, interpreting the irregular yaw motion of very large ships. Furthermore, to mitigate the chaotic yaw phenomenon of the subject ship, a concise robust integrator backstepping algorithm, incorporating the close-loop gain shaping algorithm is proposed based on the nonlinear dynamic model. It possesses a concise form and is easily implementable in marine practice. Comparative numerical experiments are conducted to validate the effectiveness and superiority of the proposed algorithm.