Autonomous Underwater Vehicle Dynamic Model Identification using Estimation of Hydrodynamic Coefficients

Hydrodynamic coefficient estimation is an essential part of underwater vehicle dynamic model design procedure. Due to existence errors in analytical calculation methods, results of the methods are not reliable. Also, determination of the coefficients by experimental test is a difficultly and costly work. This procedure due to nonlinear behavior of the system has some problems. A suitable solution is using estimators for the coefficient estimations that the estimators can present suitable estimation of coefficients using experimental tests. Also, the estimator output can be used in the design of the system adaptive control. In this paper, equations of motion of an autonomous underwater vehicle (AUV) in six degree of freedom for coefficients estimation are properly modeled. Then, using of Extended Kalman Filter (EKF) and reduced order measurement with respect to similar methods, all of viscous damping coefficients are estimated. The method is implemented on an actual AUV and the results indicate a good performance of proposed method.