Command filtered backstepping design in MOOS-IvP helm framework for trajectory tracking of USVs

This article describes design and simulation implementation of a nonlinear controller for an underactuated surface vehicle. The controller is designed using a command filtered backstepping (CFBS) approach. Theoretical background for controller design is given in the first part of this article. This nonlinear controller can be used for accurate tracking of a complex trajectory, for example a circular trajectory. Second part of the article focuses on implementation in the MOOS-IvP framework. This framework allows for flexibility in control and mission planning. Guidance is covered by the MOOS-IvP implementation of the controller while the COTS autopilot handles low-level control. The control performance is verified in simulation which confirms arbitrarily small tracking error. This paper presents simulation results where external disturbances, such currents, are also simulated and compensated for.