Top angle control and vibration reduction of flexible marine risers

In this article, control of the flexible marine riser top angle and the reduction of forced vibration under a time-varying distributed load are considered using boundary control approach. A torque actuator is introduced in the upper riser package and a boundary control law is designed for riser angle control and vibration reduction with guaranteed closed-loop stability. The proposed controller is independent of system parameters, thus possesses stability robustness to variations in parameters. Numerical simulations with a worst case excitation are provided to verify the effectiveness of the approach presented.