Simulation of the hydrodynamics of underwater vehicles as an aid to control system design

The operational demands of modern underwater vehicles pose problems which test the ingenuity of the control engineer. Classical design methods can be adequate for such a vehicle but may be found lacking when a modular vehicle configuration changes from mission to mission, or when hydrodynamics are inherently nonlinear, as in the case of many remotely operated vehicles (ROVs). Modern methods of control have the potential to overcome such limitations but their effectiveness requires proper assessment. An ideal testbed is a prototype vehicle or a scaled model. In water trials are, however, time consuming and expensive to undertake and preliminary tuning and assessment of a controller using a simulation would help to focus the experiments. The paper describes the use of a six-degree of freedom computer simulation of the hydrodynamics of underwater vehicles prior to design of attitude control schemes. Work to validate the simulation and to tune it to the underwater vehicles is discussed and the direction of the authors´ future work in this area is presented