Robust global sliding model control for water-hull-propulsion unit interaction systems - Part 1: System boundary identification

Nepredviđene jake deformacije trupa uzrokovane težinom valova mogle bi značajno utjecati na dinamičko ponašanje pogonskog sustava velikih brodova, rezultirajući slabljenjem upravljačke funkcije broda. U ovom se radu predlaže upravljanje novim globalnim kliznim modelom (GSMC) za brodske sustave voda-trup-pogonska jedinica u svrhu poboljšanja upravljačkih performansi. Taj GSMC najprije je primijenjen u razvijanju modela za upravljanje brodskim pogonom s nelinearnim nesigurnostima. U GSMC modelu primijenjena je metoda funkcije zasićenja za isključenje podrhtavanja na kliznoj površini. Zatim je pomoću Lyapunova kriterija stabilnosti potvrđena stabilnost upravljačkog sustava. Po prvi puta, granični problem nesigurnosti nelinearnog modela kvantitativno je istražen. Nesigurnosti graničnog nelinearnog modela potrebne u predloženom GSMC modelu, uključujući gubitak /varijacije zakretnog momenta motora, prijenos energije za različite uvjete opterećenja i brzine rotacije osovine, dobivene su na temelju eksperimenata provedenih na liniji brodski osovinski vod – probni stol integriranog pogonskog sustava kao i pokusne plovidbe na moru broda za prijevoz rasutog tereta. Postignuta je gornja granica od 1,85 % za nesigurnost modela, i ona bi se trebala unijeti u GSMC za integrirani brodski pogonski sustav kako bi se izveo ukupni upravljački zakon za realizaciju izdržljivog upravljanja sustavaUnexpected severe hull deformation caused by the wave loads would significantly influence the dynamical behaviours of the propulsion system in large scale ships, resulting in degradation of the ship control performance. A new global sliding model control (GSMC) for marine water-hull-propulsion unit systems is proposed to obtain more accurate control performance in this paper. The GSMC was firstly employed to establish the marine propulsion control model with nonlinear uncertainties. In the GSMC model, the saturation function method is applied to eliminate chattering on the sliding surface. Then the Lyapunov stability criterion is adopted to confirm the stability of the control system. Following, for the first time, the boundary problem of the nonlinear model uncertainties were investigated quantitatively. The bounded nonlinear model uncertainties required in the proposed GSMC model, involving engine torque loss / variations, power transfer for various load conditions and shaft rotational speeds, were derived based on the experiments carried out on a marine shaft-line test-bed of the integrated propulsion system as well as a sea trial implemented for a running bulk carrier. An upper boundary of 1,85 % for the model uncertainty has been obtained, which would be introduced into the GSMC for the integrated marine propulsion system to derive the total control law realising the robust control of the system