Depth and heading control for autonomous underwater vehicle using estimated hydrodynamic coefficients

Depth and heading control of an AUV are considered for the predetermined depth and heading angle. The proposed control algorithm is based on a sliding mode control using estimated hydrodynamic coefficients. The hydrodynamic coefficients are estimated with the help of conventional nonlinear observer techniques such as sliding mode observer and extended Kalman filter. By using the estimated coefficients, a sliding mode controller is constructed for the combined diving and steering maneuver. The simulation results of the proposed control system are compared with those of control system with true coefficients. It is demonstrated that the proposed control system makes the system stable and maintains the desired depth and heading angle with sufficient accuracy