Vibration Control of a Riser-Vessel System Subject to Input Backlash and Extraneous Disturbances

This brief addresses the vibration control of a marine riser-vessel system influenced by extraneous disturbances and input backlash. By resolving the backlash nonlinearity as an expected control signal and a nonlinear error, this backlash error and extraneous disturbance are visualized as an unknown “disturbance-like” item, and then an adaptive control strategy is established to achieve the riser’s vibration abatement and compensate for the “disturbance-like” term’s unknown upper-bound. The Lyapunov’s criterion is exploited to analyze and demonstrate the bounded stability in the controlled system. Simulation examples are finally provided to demonstrate the applicability and effectiveness of the presented scheme.