Optimal Adaptive Anti-Disturbance Control for DP of Vessels via Finite-Time Velocity Observer with Thruster Constrains

In order to estimate the unmeasurable velocities of dynamic positioning system of vessels quickly and consider reducing energy consumption, modelling errors and the ocean unknown disturbances, this paper proposes an optimal adaptive anti-disturbance constrains control scheme via finite-time velocity observer. Firstly, a fuzzy logic system is utilized to approximate modeling errors, and the finite-time velocity observer is established to obtain velocities quickly. Then, a disturbance observer is used to estimate the unknown disturbances. An auxiliary system is designed to compensate the effects of constrains. Based on the obtained velocities and disturbances information, the whole controller is composed of the adaptive anti-disturbance controller and the optimal compensation term designed by adaptive dynamic programming. It can be proved that all the signals in the closed-loop system are bounded. At Last, the simulation results verify the effectiveness of the proposed optimal control scheme.