Disturbance Estimation for Feedforward Control of Inland Vessels

Abstract

The methods presented in this paper were designed to improve the performance of a control scheme for the automatic track-keeping of inland vessels. The performance of this control scheme heavily depends on the underlying models as it employs model inversion for the calculation of feedforward input signals and reference trajectories for feedback control. However, vessels on rivers are subject to model uncertainties as well as disturbances, such as cross currents or wind. Therefore, an estimation scheme was designed for the estimation of disturbances and their integration into the model inversion procedure. Simulation results show the usefulness of the presented methods for various disturbances and model uncertainties.

Continuous-time system identification of a ship on a river

“…Thus, the relative speed is also available using (12) without any problems. On the other hand, the course of the water α w can be reasonably approximated by the course of the guiding line α GL (see more in [23]), i.e.,…”

Closed-Loop Identification and Control of Inland Vessels

“…Thenˇis computed using the components of v abs in the axes x b and y b . On the other hand, the course of the water˛w can be approximated by the tangential direction of the guiding line˛G L (see more in [22]), i.e., In electronic charts for navigation systems, the guiding line is an a-priori given reference line, which is nearly parallel to the course of the river. This guiding line is used for automatic track-keeping.…”

“…The information of the guiding line and the set-point filter is then combined in the desired track block. Then, given the desired course angle˛s, desired curvature Ä s , and desired curvature derivative Ä 0 s in , the set-point generator, based on the inverse drift dynamics model, computes the desired state variables x s in time domain [4,6,22],…”

“…Afterwards, in the late 1990s, the Max Planck Institute for Dynamics of Complex Technical Systems in Magdeburg joined the project. During all these years, different track-keeping controllers for inland navigation have been proposed (see, for instance, [4,6,21,22,32]). In this study, we consider a model-based approach, which requires a ship dynamics model that is both accurate and simple.…”