Sliding mode control, due to its robustness against modelling imprecisions and external disturbances, has been successfully employed to the dynamic positioning of remotely operated underwater vehicles. In order to improve the performance of the complete system, the discontinuity in the control law must be smoothed out to avoid the undesirable chattering… (More)
Two models for ship roll motion and capsizing under stochas-tic excitation are analyzed using Melnikov's method and control set analysis. The predictions given by these two methods are compared.
In this work an algorithm for on-line estimation of the nonlinear hydro-dynamics in underwater vehicles is presented. The algorithm is able to estimate physical parameters from natural operation signals. Identifiability and convergence of the parameter trajectories are analyzed. The application of the algorithm to a spherical vehicle is described with… (More)