Boundary control of a flexible marine riser

In this paper, vibration reduction of a flexible marine riser is studied by using boundary control method and Lyapunov´s direct method. To achieve more accurate and practical dynamic behavior of the riser, the effects of time-varying internal fluid are considered in riser´s dynamic model, which is modeled by a partial differential equations coupled with ordinary differential equations involving functions of space and time. Boundary controller is designed at the top boundary of the riser based on Lyapunov´s direct method and presented model to reduce the riser´s vibrations. The uniform boundedness and closed-looped stability are proved based on the proposed boundary control. Simulation results verify the effectiveness of the proposed boundary control.