Boundary Control of a Flexible Riser With the Application to Marine Installation

This paper investigates the control problem of a marine riser installation system. The riser installation system consisting of a vessel, a flexible riser, and a subsea payload is modeled as a distributed parameter system with one partial differential equation and four ordinary differential equations. Based on Lyapunov´s direct method, adaptive boundary control is proposed at the top and bottom boundaries of the riser to position the subsea payload to the desired set point and suppress the riser´s vibration. With the proposed control, uniform boundedness of the steady-state error between the boundary payload and the desired position is achieved by suitably choosing the design parameters. Numerical simulations are presented for demonstrating the effectiveness of the proposed control.