Modeling, identification and control of dynamic systems subject to complex vibrations are challenging problems of special interest in the field of automatic control. The project focuses on the active control of vibrations in flexible structures subject to external excitations. It has a basic character but oriented to providing knowledge and tools of potential practical application, mainly in the field of offshore wind turbines. The main purpose is finding active controllers to mitigate vibrations. Results are expected both from a theoretical and a practical (new experiments and possible application on real floating wind turbines) perspective. University of Agder and UPC teams have cooperated in the modeling, identification and control of uncertain systems and their application to mechatronic systems and intelligent structures. The UiA motion laboratory is part of the Norwegian Centre for Offshore Wind. In recent years, partners have contributed to the general state of the art on modeling, identification and control of systems. The project seeks to consolidate such interdisciplinary research of teams with a mathematical and engineering backgrounds.
Summary of project results
The project proposed new objectives addressing the application of advanced structural control technologies to offshore power generation with floating wind turbines, following a continuity line of previous projects and taking advantage of the developed results on modelling, identification, controller design, numerical and experimental validation. In recent years, it has been remarkably developed a line of vibration control in structures subject to the actions in the base. In most cases, however, the models are considered affected by external vibrations in only a single direction (one degree of freedom). In very few cases have been taken into account disturbances or multidirectional vibrations. A significant innovation in this project was to consider systematically excitations in all possible degrees of freedom. This extends the scope of active vibration control of systems, while motivating the need to develop theoretical tools. All parts of the project were innovative in the sense that the research provided advanced methodologies for modelling, identification and control that could be applied to a wide range of processes and systems of general interest in different fields of production, which dynamics can be described by using large-scale systems with uncertainties. The obtained results can be applied to floating wind turbines, another challenge in the creation of mechanisms allowing clean energy. In norther Europe, there are currently some experimental wind farms with the idea of developing better wind turbines. The project was divided in four theoretical and experimental blocks. None of them was carried out by a single group since it involved the integration of different tasks. Some meetings between the principal investigators of the UPC and the UiA took place, with the aim of evaluating the progress of the project, to propose communication activities to disseminate the results and to prepare new tasks. During this period, two papers were published in journals included in the journal Citation Reports, together with two proceedings in International Conferences. Moreover, another paper was accepted and will be published soon.
Summary of bilateral results
Partners have established close relationships and expect it to continue, both among them as well as partnerships with companies and other institutions. Main contribution of the University of Agder was the experience of Professor Hamid Reza Karaimi and the possibility of using the important mechatronic laboratory at the Norwegian university, which is equipped with high technology. Taking advantage of their respective networks and skills, partners have established a very close relationship with two companies, National Instruments and Asoindel, maintaining regular contact with them. Professor Hamid Reza Karimi has established contacts with other several companies devoted to offshore wind turbines, as the Norwegian Center for Offshore Wind (NORDCOWE), a consortium with partners form industry and science. An objective of NORCOWE is to study modelling, stability analysis and design of networked-based supervisory control for offshore wind farms. The network under consideration is modelled with random communication delay and uncertainties, which is a new research area in control systems. Then, partners consider that NILS project results may be partially applied to wide areas of interest. The finished project has served as starting point for the preparation of a new project that will be the continuation of the current one and the final consolidation of the work team. Partners have applied to the Spanish Ministry of Economy and Competitiveness for the period 2016-2019. The main beneficiaries of the project were not only the investigators of both Universities, the UPC and the UiA, but also other companies and research groups interested in this field. Moreover, the groups have a great potential for training new PhD students, and it is expected that part of the scientific and technological developments will provide several PhD theses. At the time of the closure of the project, the group of the Universitat Politècnica de Catalunya has PhD students working in related areas and a similar situation occurs at the University of Agder, with PhD students interested in these issues.