Vibration Suppression of a Flexible Riser by Boundary Iterative Learning Control

This paper studies the vibration suppression problem of nonlinear flexible riser systems subjected to external disturbances. For suppressing the vibration and improving the control precision, a novel joint control method which includes boundary control and iterative learning control (ILC) is raised, via finite-dimensional backstepping control and Lyapunov's direct method. Iteration term is first designed in discrete domain and then transformed into continuous time domain Under the action of the proposed boundary-ILC, the uniform boundedness of closed-loop system state and the convergence of the system output are proved by using Lyapunov synthesis. Finally, simulation results are provided to illustrate the effectiveness of the formulated control approach.