Coupled Nonlinear Flexible Marine Riser
In Chap. 7, boundary control for a coupled nonlinear flexible marine riser with two actuators in transverse and longitudinal directions is developed to reduce the riser’s vibrations. The dynamic behavior of the flexible riser is represented by a distributed-parameter system (DPS) model with partial differential equations (PDEs), and the control is applied at the top boundary of the riser based on Lyapunov’s direct method to suppress the riser’s vibrations. With the proposed boundary control, the uniform boundedness under ocean current disturbances and exponential stability under free vibration condition is achieved. The proposed control is independent of system parameters, which ensures the robustness of the system to variations in parameters.
KeywordsFatigue Vortex Transportation Drilling Riser