Rudder-Roll Damping Controller Design using Mu Synthesis

The effectiveness of rudder roll damping control is very sensitive to uncertainty in ship dynamic parameters. In this paper, an H-infinity controller is designed using mu synthesis and an uncertainty model for roll and yaw that was identified earlier from experiments at sea. The properties of the resulting controller are discussed and seaway simulations with linear and non-linear models of a container ship illustrate the controller performance. The simulation results show that the mu synthesis controller is able to obtain robust performance over an envelope of operational conditions.