Dynamics modelling, performance evaluation and stability analysis of an autonomous underwater vehicle

This paper describes the viability of applying non-linear controllers and line of guidance methods to manipulate different motion regimes of an autonomous underwater vehicle (AUV) without any assumptions. The modelling component includes vehicle dynamics, external forces acting on the vehicle and environment. So far, diving dynamics of an AUV have often been derived under various postulations on the motion of the vehicle. However, these kinds of assumptions may induce large modelling errors and may cause further severe problems in many practical applications. A position and attitude tracking control law for (AUVs) in six degrees of freedom is decoupled into longitudinal and lateral motions such that autopilots for speed, depth/diving and heading control can be designed. A numerical simulation demonstrates that the proposed controllers make the system stable and maintain the desired depth and heading angle with sufficient accuracy. Phase plane analysis is used to study the stability of the whole system.