Description
The use of aero dynamical systems in the Arctic environment has recently increased. The presence of strong winds makes wind turbines an efficient source of renewable energy. Due to the critical weather conditions in the Arctic region, icing of such systems can occur and cause undesired behaviors, as loss of performances and risks of failures that could be avoided using anti-icing techniques. For this reason, it is important to obtain an estimation of the amount of icing affecting these systems using a mathematical model of this phenomenon. Linear Parameter Varying (LPV) techniques allow taking into account the variation of the icing according to different weather conditions, and could be an efficient paradigm to tackle this problem. The goal of this project is to apply these techniques for estimating the icing in aero dynamical systems. The project promoter, Polytechnic University of Catalonia, has a solid background on LPV systems, with relevant peer-reviewed journal and conference publications on related subjects. The project promoter may take advantage of the experience and expertise of the donor partner (Norwegian University of Science and Technology (NTNU) on the topics of estimation and icing models, to further develop the techniques being applied to other industrial and scientific community problems. The results will benefit the scientist community.
Summary of project results
In recent years, the use of aerodynamical systems in the Artic environment has increased. However, due to the critical weather conditions found in the Artic region, icing of such systems can occur and cause undesired behaviours, like loss of performances and risks of failures. For this reason, it is important to obtain an estimation of the amount of icing affecting these systems using some mathematical model of this phenomenon. Among the possible techniques, linear parameter varying (ÑPV) ones allow taking into account the high variation of the icing behaviour according to different operating and environmental conditions. The aim of the project was to apply the LPV techniques to the problem of estimating the icing in aerodynamical systems. The scientific activity developed within this project led to a thorough study of the state-of-the-art of several topics related to the above mentioned goal, in particular with respect to aerodynamics, UAV models, icing formation, and techniques that could be applied to the problem of icing detection. Taking into account this study, the theory of unknown observers (UIOs) has been applied using a LPV paradigm, with the development of the following solutions to the problem of icing detection: - LPV proportional unknown input observer; - LPV proportional integral unknown input observer; - LPV proportional integral unknown input interval observer. These solutions have been obtained starting from a simplified problem, where noise in the sensors and uncertainties in the model were neglected, In this case, it was found that a LPV proportional unknown input observer was able to correctly detect/isolate the presence of actuator faults and icings in UAVs working under varying operating conditions. When noise in the sensors has been added, it has been demonstrated that the addition of an integral action was necessary in order to improve the property of noise rejection, leading to the LPV proportional integral unknown input observer. Finally, an interval formulation has allowed taking into account the uncertainty in the model. Three joint scientific papers have been prepared and submitted, two of them already accepted. The results obtained have contributed to the state-of-the-art of solutions to the problem of icing detection, and therefore to the improvement of the properties of UAVs, in the case in which they should work under arctic conditions.
Summary of bilateral results
The cooperation scheme has allowed the awarded researcher to start a professional relation with Prof. Johansen and Dr. Ciristofaro. Moreover, the awarded researcher has established contact with several Ph.D students at the host department. The partnership has provided the opportunity to begin a fruitful collaboration between researchers of both universities involved in the cooperation, Technical University of Catalonia and Norwegian University of Science and Technology. Also, some of the obtained results could be used for further experiments within the research projects developed by both the host and the promoter universities. In addition to the obtained results, there has been a lot of discussion about open problems in the field of icing detection, leading to possible ideas on how to tackle them. There is a strong wish to further collaborate In order to develop these ideas, and contribute further to the advancement of the state-of-the-art of icing detection in aerodynamical systems, also with regards to the application to icing detection in wind turbines. The project partner has contributed to the project through the experience of the involved researchers, with particular regards to the scientific background about the icing and fault detection problems in UACVs, UIOs with disturbance decoupling using algebraic methods. Moreover, future experiments to validate the theoretical results are forecasted, and the project partner will provide the necessary equipment to perform such experiments.