Design a Two-step Master-slave Control Law for Zero-speed Fin Stabilizers
零航速减摇鳍两步主从控制律设计

The essential difference exists in the hydrodynamics between the zero-speed and the lift-based fin stabilizers. For the former, a dynamic nonlinear mapping with constraints between the fin angle, angle rate and angle acceleration is established. However, since this mapping does not satisfy approximate linear relation, the opposed PID control method can not be used. For solution of the dynamic input nonlinearity employed by the zero speed fin stabilizer system, a two-step master-slave control law consisting of a variable constrained model predictive controller and a numerical iterative inverse controller is proposed by means of the nonlinear removal strategy for the special structure. The simulation results show the good performance of the controller designed but the anti-roll efficiency under zero speed degrades nonlinearly with increasing sea conditions due to hard constraints induced by physical reasons.