Experimentation Research On Examination Platform Of Passive Type Anti-rolling Tank

The anti-rolling tank is one of the most popular used stabilizing equipments, and it fits for ships working at zero speed or low speed such as passenger and train ferry, roll-off vessel, research and exploration vessel and so on in particular. It can be classified as U-tube tank stabilizer and flume anti-rolling tank according to structural configuration, and the former has three types, namely passive, active control and controlled passive tank in terms of the control mode.The paper is based on the item the Anti-rolling Tank Test Equipments on the Ship among the country 211 key construction projects. The design and realization of examination platform and relative theoretical questions are analyzed and further discussed.The examination platform of anti-rolling tank is a kind of special complex system. So far the country has no such examination equipments in a large scale. The platform test can provide the basis for the design of anti-rolling tank and test data for ships with anti-rolling tank.To test the performance of anti-rolling tank more conveniently, the paper sets up the examination platform of two freedoms. The platform can simulate rolling and swaying motion of the ship. And the moment of inertia, damp and comeback can be adjusted. The rolling moment and the swaying force were simulated respectively by two electro-hydraulic servo systems. The two systems both use electro-hydraulic servo valves, in which the analog rolling moment system adopts gear-rack swing hydraulic-pressure oil vat with torque sensor, while the analog swaying force system employs double shanks hydraulic-pressure oil vat with two pressure sensors and a placement sensor.Models of electro-hydraulic servo valve, gear-rack swing hydraulic-pressure oil vat and torque sensor are selected in order to analog the rolling moment more accurately. The transfer function of electro-hydraulic moment servo system is presented and the system parameters are gained. At the same time, the simulation of system is studied. What's more, the application of PID control, apices configuration and PID control based on NN-BP in the electro-hydraulic servo system is developed. The simulation results show that the control strategies are in effect.Considering the realization of the system, the paper adopts incremental mathematical PED controller and manufactures the power board, servo amplified board and signal processing board. And the hardware circuit and sensors arechecked and debugged. The result is very good.According to the examination platform, the monitoring control system based on computers is designed, which can output voltage signals of rolling moment and swaying force that regular wave and irregular wave press on the ship. The system also gathers and analyzes test data from the sensors. The test results are appearing on the screen in real time. The system has elementary intelligently functions. The test requirements can be accomplished through the experiment.In the end, the test results of the examination platform for anti-rolling tank model are presented. The test results indicate that test rolling table can simulate ship rolling motions on the wave and passive U-tube tank designed achieves stabilization effects to a certain extent. Test result is in accord with estimated value for the natural frequency of tank. Forced oscillation test results of rolling table show that the theoretical analyses are good in accordance with test results under condition of the different vertical location of tank within the ship, different water level of wing tanks and different opening of the damping baffle respectively.In conclusions, the successful development of examination platform provides a stabilized test bench for ship equipped with anti-rolling tank to predict roll motion accurately and reliably. The research findings and conclusions would play an important guidance role in design of the U-tube anti-rolling tank system and simulation of the test rolling analog table.The equipment is permitted by the country 211 projects in Jun. 2001.