Nonlinear Control of Marine Surface Vehicles without velocity measurement

The paper deals with the tracking control of Marine Surface Vehicles without velocity measurement. An auxiliary filter is used to generate a velocity signal for the tracking error dynamics. Although the filter-based approach has been used before, this paper has two new contributions – unlike in literature, the approach in this paper doesn’t require the acceleration signals for computing the real input force. Secondly, the use of barrier Lyapunov functions has never been explored for marine vehicles when using the filter approach, whereas in this paper, the filter-based approach is combined with the use of barrier Lyapunov functions for improved transient response. Furthermore, unlike in literature on the use of filters without velocity measurement for marine vehicles, the inertia, Coriolis and damping matrices are assumed to be time-varying and external disturbances are also considered. The control law is designed using adaptive control methodology. Model uncertainties are effectively rejected by the nonlinear control law. Closed loop- system stability is proved via Lyapunov Theory. Results from numerical simulations are presented to validate the effectiveness of the proposed approach.