Numerical and experimental studies on a predictive control approach for pitch stabilization in heading waves

摘要

A predictive control approach is proposed to reduce pitch. In this method, a controller consisting of a short-term predictor, a force estimator and an attack angle allocator is developed to reduce pitching. The online estimation of hydrodynamics is the essential part of the control approach. Pitch and heave motions are predicted in real-time with the short-term predictor. The predicted motions are then employed in the force estimator to forecast the ship's hydrodynamics online, where the dynamic equilibrium between ship motions and external forces is applied. The predicted hydrodynamic forces, regarded as expected stabilizing forces, are further applied to evaluate the optimal effective attack angles of the fin actuator. Active fins are allocated based on the estimated optimal effective attack angles. For evaluation purposes, the numerical simulations and experimental tests of pitch stabilization on a ship model under various sea states are investigated. Both results suggest that the predictive control approach performs satisfactorily in terms of pitch stabilization.