Predictive control and stabilizing effect analysis of controlled passive tank

Controlled passive tank is able to achieve a more perfect stabilizing effect by extending the natural period of water tank with opening/closing the air-valves in accordance with the variation tendency of ship´s rolling. Two controlling parameters, which are most important, are the closing-time and closing time span. The determination of closing time span has a direct relation with the ship´s real-time rolling period. By adopting wavelet neural network to predict the ship´s rolling motion and real-time updating the closing time span of closing valves with the predicted values, meanwhile, real-time analysing the rolling power spectrum is applied before and after anti rolling according to the known input-output relation of anti-rolling tank model coupled with rolling. The paper shows this predictive control method which is more perfect than traditional anti rolling control effect and possess favourably practical value in engineering.