Simulation Research On Cooperative Operation Process Of Underwater Platform And Submersible

Taking the dynamics characteristics of deep-sea hoisting system as the research object,the multi-domain modeling language Modelica was applied to create the motion model of underwater platform,cable and suspended object in MWorks environment,and completed the coupling and unified solution of the three.With the dynamic motion of the underwater cable as the research focus,the collaborative operation process between the underwater platform and the object to be hoisted under the deep-sea lifting condition is simulated.The overall simulation framework of the motion model of the deep-sea hoisting system is divided at first.Based on the characteristics of Modelica language,the establishment and simulation process of each motion module are defined,and the interface connector between the modules is given.For the underwater platform and the object to be hoisted,based on the characteristics of modeling theory of underwater vehicle motion,the simulation framework is divided and a general object-oriented method of underwater vehicle motion modeling is proposed.Then,the specific process of writing simulation code based on declarative property of Modelica is given and the solution is implemented by the acusal formulation.Finally,the underwater platform motion model is established according to the hydrodynamic coefficient measured by the sea trial,the correctness and convenience of the modeling method are proved by simulation results.The euler method is applied to solve the cable steady state problem,and the simulation results show that the steady state modeling is of high accuracy.Focus on exploring the underwater cable dynamic movement,using the finite difference numerical method and Newton iteration method,dealing with the coupling problem of partial derivative term and non partial derivative terms in the governing equation,the difference scheme is reconstructed and the error control loop is added in the solution process.The comparison between the simulation results and the sea trial verifies that the solution method can satisfy the engineering requirements.The problem of variable cable length in the process of cable retracting and releasing is briefly analyzed and the interpolation method of state variables is given.The difficulties in implementing variable cable length simulation using Modelica language are explained,and the simulation code is written based on the block diagram.Model of the equilibrium system and the adsorption force of the object to be lifted are built,and the overall simulation of the deep-sea hoisting system is taken as the key point finally.Takingsuspended objects as unpowered weights and submersibles respectively,the motion model of the established undersea platform,cable and the object to be lifted are coupled,change of space cable shape and tension,velocity and attitude angle of underwater platform and submersible to be lifted during the process of collaborative operation are analyzed in detail.The work of this paper fills up the blank in the research field of dynamic characteristics of underwater cable connected multi-body system,which can provide reference for the implementation of deep-sea lifting task,and can also be used in the training process of operators,with certain engineering application value.