A nonlinear parametric model of a torque-controlled thruster is developed and experimentally confirmed. The model shows that the thruster behaves like a sluggish nonlinear filter, where the speed of response depends on the commanded thrust level. A quasi-linear analysis which utilizes describing functions shows that the dynamics of the thruster produce a strong bandwidth constraint and a limit cycle, which are both commonly seen in practice. Three forms of compensation are tested, utilizing a hybrid simulation combining an instrumented thruster with a real-time mathematical vehicle model. The first compensator, a linear lead network, is easy to implement and greatly improves performance over the uncompensated system, but does not perform uniformly over the entire operating range. The second compensator, which attempts to cancel the nonlinear effect of the thruster, is effective over the entire operating range but depends on an accurate thruster model. The final compensator, an adaptive sliding controller, is effective over the entire operating range and can compensate for uncertainties or the degradation of the thruster.
The influence of thruster dynamics on underwater vehicle behavior and their incorporation into control system design
Der Einfluß der Triebwerksdynamik auf das Verhalten von U-Booten und seine Berücksichtigung beim Entwurf des Steuerungssystems
IEEE Journal of Oceanic Engineering ; 15 , 3 ; 167-178
1990
12 Seiten, 11 Quellen
Aufsatz (Zeitschrift)
Englisch
Preliminary thruster control experiments for underwater vehicle positioning
Tema Archiv | 2006
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