Research On Configuration Design And Driving Of All-weather Active Rocking Test Ship

The movement of ships is affected by the natural environment,such as rolling,pitching and heave under the interference of sea waves,sea breeze and ocean current.The unstable movement of ships seriously affects the take-off and landing accuracy of carrier-based aircraft,the performance and service life of shipborne instruments and equipment,and the launching accuracy of rocket shells.In severe cases,it will cause the hull to overturn and threaten the safety of personnel.The existing test ships and land moving platforms can simulate the multi-degree-of-freedom motion of ships on the sea surface,but the test ships have high cost and long production cycle,and the experimental process is limited by the natural environment,so the test can only be carried out until the corresponding sea conditions;The freedom degree of the land mobile platform is artificially controllable and can not be restricted by the environment,but the platform size and load capacity are limited,which can not provide an operating environment for heavy-duty equipment of ships.Based on the limitations of the above two methods,this paper puts forward the innovative design of the all-weather active swing test ship.The test ship has multiple sets of power devices,can realize autonomous swing without depending on the sea conditions at all levels,and simulates the attitude movement of the ship in full scale,thus providing a semi-physical simulation environment for carrier-based aircraft and shipborne instruments and equipment.Firstly,the design scheme of realizing the six-degree-of-freedom motion of the ship is put forward,and the ship coordinate system and geodetic coordinate system are established to express the change of the ship’s posture.According to the design principle that it is easy to realize the ship’s rocking without capsizing,three types of test ships are designed with reference to the existing ship types.Taking the rolling motion as an example,the torque balance equation under the action of driving force is written,and the mathematical model for solving the driving force torque is obtained.Secondly,check the stability of three ship types.First,the initial stability of three ship types is checked,then the P-M spectrogram under the condition of meaningful wave height is studied,and the wave simulation analysis is carried out with Fluent.The stability under the condition of Grade 5 sea state is judged by Lyapunov criterion.After comprehensive comparison,it is concluded that all three ship types meet the design requirements of stability.Then,the driving performance of three ship types is compared and analyzed.The gravity moment,buoyancy moment and resistance moment of three ship types under different roll angles are solved respectively,and the curves of driving force moment of three ship types changing with roll angles are obtained.Finally,it is concluded that the driving moment required by U-shaped test ship is the smallest under the same conditions,which provides theoretical basis for the selection of test ship.Finally,the driving scheme is studied.Multi-point variable vector thrust drive is adopted.By analyzing the six-degree-of-freedom motion state of the ship,the optimal combination of driving quantity and driving position is configured.The existing mainstream propulsion modes of the ship are integrated,and the water jet thrusters which are easier to realize variable vector thrust are selected as driving devices,which are uniformly installed on the test ship.