Adaptive techniques applied to offshore dynamic positioning systems



Document title: Adaptive techniques applied to offshore dynamic positioning systems
Journal: Journal of the Brazilian Society of Mechanical Sciences and Engineering
Database: PERIÓDICA
System number: 000312329
ISSN: 1678-5878
Authors: 1
1
2
Institutions: 1Universidade de Sao Paulo, Departamento de Engenharia Naval e Oceanica, Sao Paulo. Brasil
2Universidade de Sao Paulo, Escola Politecnica, Sao Paulo. Brasil
Year:
Season: Jul-Sep
Volumen: 28
Number: 3
Pages: 323-330
Country: Brasil
Language: Inglés
Document type: Artículo
Approach: Experimental
English abstract Dynamic positioning systems (DPS) comprise the deployment of active propulsion to maintain the position and heading of a vessel. Several sensors are used to measure the actual position of the floating body, while a control algorithm is responsible for the calculation of forces to be delivered by each propeller, in order to counteract all environmental forces, such as wind, waves and current loads. The controller cannot directly compensate motions in the sea waves frequency range, since they would require an enormous amount of power to be attenuated, possibly causing damage to the propeller system. That is the reason why a filtering algorithm is to be put in place to separate high-frequency components from the low-frequency ones, which are, then, fed into the control loop. Usual commercial systems apply Kalman filtering technique to perform such task, due to the smaller phase-lag introduced in the control loop compared to conventional low-pass filters. The Kalman filter draws on a model of the system to be controlled, which, in turn, depends on an unknown parameter, related to the wave frequency. Adaptive filtering is called upon with a view to perform an on-line estimation of such parameter. Most control algorithms, however, rely on fixed gains, thus making it possible for a noticeable performance degradation to take place in some situations, as those associated to mass variation during a loading operation. This paper presents the application of model-reference adaptive control (MRAC) technique to DPS's, cascaded with the commonly
Disciplines: Ingeniería,
Ciencia y tecnología
Keyword: Equipo y maquinaria,
Oceanografía,
Embarcaciones,
Propulsión,
Oleaje,
Algoritmos,
Controladores,
Control adaptativo,
Filtro Kalman,
Sistema de posicionamiento dinámico,
Dynamic positioning system,
Kalman filter
Keyword: Engineering,
Science and technology,
Equipment and machinery,
Vessels,
Adaptive control,
Controllers,
Oceanography
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