A synchronization motion control algorithm for multiple dynamic positioning vessels

In order to solve the synchronization control problem of multiple dynamic positioning vessels, which are expected to satisfy a given formation pattern and track a smooth reference trajectory as a whole, a synchronization control strategy based on algebraic graph theory is proposed. The strategy is realized by defining synchronization error combining the graph theory, and it makes each vessel keep in synchronization with the other neighbors of the group. The controller is designed based on backstepping and Lyapunov direct method so as to track the vessels´ desired trajectory, and the controller of each vessel is designed using the feedback from the adjacent vessels. In addition, the environment disturbances are compensated through an extended state observer of the model of the dynamic positioning vessel. The globally asymptotically stability of the error dynamics is guaranteed by theoretical analyses. Finally, the simulations results illustrate the effectiveness of the proposed coordination control method.