Boundary Constrained Control for a Flexible Marine Riser

In this article, we deal with the anti-windup design for flexible riser systems influenced by external disturbances and input nonlinear saturation. The boundary anti-windup control is developed to globally stabilize the riser system employing backstepping method, the hyperbolic tangent function is introduced to limit the control input in the designated area, and the Nussbaum function and auxiliary system are exploited to tackle the nonlinear term stemming from input nonlinear saturation. Under the derived control, the closed-loop system signal is ensured to be convergent to a specified region. In the end, the performance of the control developed is verified conducting numerical simulation.