Analysis of motion state of the tow-part underwater towed vehicle system during cable deployment

The effect of variable-length towed cable on the motion of the secondary towed vehicle should be taken into consideration during its deployment. In order to predict the motion state of the secondary towed vehicle during deploying stage and obtain the position of it and the configuration of towed cable precisely and timely, an upgraded Lagrangian method is adopted. The movement of towed cable's particles in the stages of both deploying and fixed-length is described. By the using of lumped-mass method, the kinetic model of the two-part underwater towed vehicle system is built. The towed cable configuration and the motion response of the secondary towed vehicle are calculated at different towing and deploying speed. Simulation results show that both towing speed and deploying speed have remarkable influence on the configuration and tension of towed cable and the motion state of towed vehicle, and the calculating results would also provide a theoretical basis to forecast the motion state of towed vehicle.