Active vibration control of a flexible rod in water

This paper addresses the vortex-induced vibration (VIV) suppression problem of nuclear fuel rods, which are transported by a refueling machine (RM) to given reactor locations in water. First, Hamilton's principle is used to develop the equations of coupled motions of the RM and the fuel rod. The resulting equations of the hybrid (lumped-mass RM and distributed-parameter flexible rod) system are then utilized to investigate the VIVs of the fuel rod upon the movements of the RM. Then, a boundary control scheme is developed to suppress the VIVs of the rod in the course of its transportation in water. Furthermore, Lyapunov function-based stability analyses are performed to prove the uniform ultimate boundedness of the closed-loop system, considering the influence of the nonlinear hydrodynamic force acting on the fuel rod. Finally, simulations are performed to demonstrate the effectiveness of the proposed boundary control scheme.