Control design for a vibrating flexible marine riser system

In this study, we address the global stabilization issue of a flexible riser system subject to input saturation and external disturbances. Based on Lyapunov theory and backstepping method, the boundary control is developed by introducing a smooth hyperbolic tangent function, an auxiliary system and a Nussbaum function. The uniformly bounded stability of the closed-loop system is analyzed and proven without simplifying or discretizing the infinite-dimensional dynamics. Simulation results illustrate that the control designed works well in handling the input saturation and suppressing the vibration.