Research on inflation and floating-up process of unmanned underwater vehicle based on collaborative simulation technology

For solving the problem of unmanned underwater vehicle (UUV) recovery, a multidisciplinary collaborative simulation method is proposed to simulate the inflatable deployment of an annular airbag and the motion of an UUV: a) a deployment dynamic model of the underwater airbag is established, the volume expansion rate curve of the airbag during the inflatable deployment process based on the control volume algorithm is obtained, and the accuracy of the model is verified by experiments; b) under the condition of a constant volume expansion rate of the airbag, a hydrodynamic model that couples the six-degree of freedom rigid body motion and the local deployment of the airbag is established, and calculations are performed using a custom program. The simulation method is used to study the effects of the ‘stop’ water depth on the motion characteristics of the vehicle, and the accuracy of the calculations is verified via the two-way fluid-structure interaction method. According to the calculation results for the effective deployment volume of the airbag and the motion curve of the centre of mass of the underwater vehicle, the ultimate floating depth of the vehicle can be predicted, which provides a reference for engineering implementation.