Quantitative Analysis and Design of a Rudder Roll Damping Controller

A rudder roll damping controller is designed using Quantitative feedback theory to be robust for changes in the ships metacentric height. The analytical constraint due to the non-minimum phase behaviour of the rudder to roll is analysed using the Poisson Integral Formula and it is shown how the design tradeoffs in closed-loop roll reduction can be approximated using this formula before a controller is designed. The robust roll and course keeping controllers designed are then tested using a nonlinear simulation.