Research On The Control Strategy Of A Four-stabilizer Fin System

Since the fore fins have severe hydrodynamic interference on back fins, the anti-rolling effect of the four-stabilizer fin system is not ideal, which can have further improve. At the same time, taking into account the problem of energy consumption, the research on the four-stabilizer fin system is imperative. Currently, the control strategy of the four-stabilizer fin system has been using the two-stabilizer fin system's control strategy. Researching on the control strategy of a four-stabilizer fin system has less reference, and researchers seldom consider the energy consumption. Due to analyze many references on four-stabilizer fin system and energy optimization, the performance index of four-stabilizer fin system is established. And controller is designed for simulation research according to the performance index.Analyze the hydrodynamic interference between fore fins and back fins, and the mathematical model of fin stabilizer is established, which includes the lift loss of back fin stabilizer. The controller of back fins servo system, which will make up the lift loss of back fin stabilizers, and the optimizing control strategy is designed to make the anti-rolling system achieve ideal effects of anti-rolling performance and energy optimization.The main content of this paper:Firstly, in order to research the hydrodynamic disturbances of fore fins to back fins, the fore fin stabilizer system and back fin stabilizer system are simulated by using FLUENT software. Using Matlab Curve Fitting Toolbox the coupling coefficient formula is fitted according to the Fluent simulation data. A quantitative analysis is carried out on the disturbance between fore fins and back fins according to the coupling coefficient formula and pool experiments and the model of four fin stabilizer system is established. which includes the lift loss of back fin stabilizer. Comprehensive performance indicators which include effects of anti-rolling and optimization-related are established by analyzing the mathematical model.Secondly, the feedforward dynamic matrix control algorithm is used to research on back fins servo system. Dynamic matrix is used to track and predict the change of the lift force of the fore fin system. The angle of back fins is controlled by using feedforward compensation according to the lift force difference between fore fins and back fins. By increasing the angle of the rear fin. the lift loss is compensated, and the control effect of four-stabilizer fin can be transformed into the effect superposition of the fore fin and the back system, which lay the foundation for the design of the four- stabilizer fin system controller.Finally, due to the limitation of the traditional PID controller which has good control effects only under certain sea conditions, the dual neural network is used to tune the PID parameters on-line and the adaptive control of four-stabilizer fin system is realized. Through the analysis of waves, a relatively ideal model of the wave disturbance is established.Four-stabilizer fin system is simulated under the specific sea condition and the free sea condition, and the anti-rolling effect and the energy optimization problem are analyzed.Simulation results show that this approach not only saves the time of optimizing the parameters of PID, but also improves the effect of two pairs of fin stabilizers. The novel approach ensures that the ship can achieve the double effect of ship stabilization and energy optimization under any sea condition.