Comments on ``Nonlinear Output Feedback Control of Dynamically Positioned Ships Using Vectorial observer Backstepping''
Författare
Summary, in English
The decomposition of nonlinear output feedback control into an observer and a state feedback control is an open problem. A solution for dynamic positioning of ships has been proposed in the above paper (1) and by Grovlen and Fossen, where an observer-based backstepping method is used. This note points out that the observer design in the above-mentioned papers does not cover unstable ship dynamics and suggests a remedy for an extended class of ships. The proof for the nonlinear observer used in the design in the above-mentioned papers only applies to ships with stable sway yaw dynamics. In the above-mentioned papers an example concerning thruster assisted mooring of a tanker is given, which does not fulfill the needed stability properties, so an extension to this case is highly motivated. We propose a method to extend the results, under a detectability condition. This condition implies stable surge dynamics, which is a natural assumption for ships.
Avdelning/ar
Publiceringsår
1998
Språk
Engelska
Sidor
439-441
Publikation/Tidskrift/Serie
IEEE Trans. Control Systems Technology
Volym
6
Issue
3
Dokumenttyp
Artikel i tidskrift
Ämne
- Control Engineering
Nyckelord
- Marine systems
- nonlinear systems
- observer design
- stability
- state estimation.
Status
Published
Projekt
- LU Robotics Laboratory
- Lund Research Programme in Autonomous Robotics, 1998-2001