Crew and systems suffer negative effects due to vertical accelerations and motions in a seaway state. This research is about the use of active appendages to smooth the motions in a fast ship.
A research project about robust and intelligent control of high speed craft was defined, with the approval and financial support from the Science and Technology Ministry of Spain. The aim of the project was to use modern (robust) control and applied to present problem of ship control. To achieve this, people from industry were asked to give inputs for present and real problems. One of these problems concern to motion sickness incidence in fast ferries.
For this case a benchmark problem was define (de la Cruz et al 2004), and a simulation tool for design and evaluation was available (Esteban et al. 2001). So this specific problem was considered as a design challenger.
In the research, a developed control system was installed in a model ship in order to move a bow T-foil, fins and flaps. Models of ship was obtained by different method (Aranda et al. 2004). Several control algorithms were tested. Mainly focused on vertical motions in pitch and heave, and their relation with roll motions. Therefore, a multivariable robust control was designed with satisfactory results.
The results of the research show an important reduction of motion and acceleration improving the crew comfort and the warship operational capabilities.
Four designs was tested: a classical PD (in order to compare with other designs) (Aranda et al. 2001), a robust control by QFT methodology (Aranda et al. 2002 shows a comparative study with classical PD control and QFT control), Fuzzy control and a multiobjetive control (Esteban et al. 2002) .
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