Control of Motion Compensated Offshore Gangway
Author
Jensen, Lukas Matz
Term
7. term
Education
Publication year
2018
Submitted on
2018-01-09
Pages
35
Abstract
This project tackles the challenging and often risky task of transferring people and equipment at sea by developing a motion-compensated offshore gangway. The focus is to design both a hydraulic actuation system and a controller to stabilize the gangway’s pitch rotation so it remains within a defined error margin under wind and wave disturbances. The scope is limited to pitch with a target of rejecting at least 90% of an incoming disturbance of 8°/s, and the pitch motion is constrained to ±20° for safety. An analytical plant model of the hydraulic cylinder drive is established through steady-state and dynamic analysis, simplification, and linearization. Based on this, a single lag compensator is designed in the frequency domain, and the full system is simulated in MATLAB/Simulink; sensors and drivers are assumed in the feedback loop but not specified. No physical testing was performed because the system has not been built, so results rely on virtual simulations. The simulations indicate that the controller stabilizes the pitch system and meets the specified disturbance-rejection criteria without inducing instability. Limitations include addressing only the pitch degree of freedom and the lack of experimental verification; future work could extend control to yaw, roll, and telescoping motions.
Dette projekt adresserer den udfordrende og ofte risikable opgave at overføre personer og udstyr til havs ved at udvikle en bevægelseskompenseret offshore gangway. Fokus er at designe både et hydraulisk aktuatorsystem og en regulator til at stabilisere gangwayens pitch-rotation, så den kan holde sig inden for en defineret fejlmargin under påvirkning af vind og bølger. Arbejdet afgrænses til pitch-bevægelsen med et mål om at afvise mindst 90% af en indkommende forstyrrelse på 8°/s, og gangwayens pitch begrænses af sikkerhedshensyn til ±20°. Plantmodellen for det hydrauliske cylinderdrev etableres analytisk gennem steady state- og dynamisk analyse, forenkling og linearisering. På denne baggrund udvikles en enkelt lag-kompensator i frekvensdomænet, og hele systemet simuleres i MATLAB/Simulink; sensorer og drivere antages i feedback-loopet, men specificeres ikke. Der blev ikke udført fysiske forsøg, da et fysisk system ikke er opbygget, og resultaterne beror derfor på virtuelle simuleringer. Simuleringerne viser, at regulatoren kan stabilisere pitch-systemet og opfylde de opstillede kriterier for forstyrrelsesafvisning uden at kompromittere stabilitet. Projektets begrænsninger omfatter udelukkende behandling af pitch-frihedsgraden samt manglende eksperimentel validering; fremtidigt arbejde kunne omfatte en samlet regulering af yaw, roll, samt udskydning og indtrækning.
[This apstract has been generated with the help of AI directly from the project full text]