Fluid Noise Control Of Ship Hydraulic Rudder System

As the power steering system of ship, the hydraulic rudder is the ship's important constituent. With the development of the hydraulic technology to high speed, high pressure and high power, the vibration and noise of the hydraulic rudder which causes by pressure impact of the hydraulic pipeline is also becoming more and more serious, the vibration and noise already became the important factor which restrict further broad application of the hydraulic rudder. Therefore, researching and analyzing the pipeline's dynamic characteristics and pressure impact and reducing the hydraulic rudder system's vibration and noise has a positive and profound influence for improving the system's performance and promoting the application of hydraulic rudder.Based on the engineering practices this paper carries on modeling and simulating to the pipeline's dynamic characteristics and pressure impact of a certain type valve control hydraulic rudder, and a Fuzzy-PID controller is designed to reduce the pressure impact which caused by start-stopping and reversing of the hydraulic rudder, therefore realizes system's vibration and noise reduction.In this paper, the noise production mechanism and the present research situation of vibration and noise reduction technology are summarized, and based on this, a certain type of valve control hydraulic rudder is analyzed and researched. First, the transfer function model of the hydraulic rudder system is built, and AMESim software is used to establish system's simulation model, consider the hydrodynamic of the rudder is the force disturbance of the rudder system; the hydrodynamic model is built and analyzed.A conventional PID controller is designed according to the system's frequency domain characteristics, and the distributed parameter model of the pipeline of hydraulic rudder system is established. AMESim software is used to carry on the dynamic characteristics simulation when the system considers or without regard to the pipeline's dynamic characteristic, then the results are compared. It is obvious that the model which considers the pipeline's dynamic characteristic have obvious pressure impact which caused by start-stopping and reversing than the model which without consider it. In addition, analyzing the influence of controller parameters on the system; therefore the direction of improvement of the controller is determined.In view of the conventional PID controller's shortcomings, a Fuzzy-PID controller is designed to realize on-line adjustment parameters, therefore realizing system's vibration and noise reduction. It is proved by adopting the joint simulation based on AMESim and MATLAB/Simulink that the Fuzzy-PID controller can effectively reduce the pressure impact which caused by start-stopping and reversing of the hydraulic rudder.