Residual vibration control of a nuclear refueling machine

This paper addresses the vibration control problem of a nuclear refueling machine (RM) that transports fuel rods to given reactor locations in water. First, Hamilton's principle is used in developing a hybrid lumped-mass and distributed-parameter model of the RM to investigate the underwater vibrations of the fuel rods caused by the RM's movements. In deriving the control law, the hydrodynamic force acting on the rod is considered nonlinear. Then, a boundary control scheme is developed, which suppresses the transverse vibrations of the rod in the course of its transportation. Furthermore, Lyapunov-based stability analysis is performed to prove the uniform ultimate boundedness of the closed-loop system, considering the influence of nonlinear hydrodynamic forces on the fuel rod. Finally, simulated rod responses are shown to demonstrate the effectiveness of the proposed control scheme.