The aim of this work was to design a control system for the shape memory alloy (SMA) actuator operated airfoil (a cross section of wind turbine blade). Design of SMA control is focused on the reliable operation of the SMA actuators. The actuator should follow the targeted shape accurately and without too much delay. Another objective is to avoid overheating which is the most critical damage to the structure. SMA actuator shape control is in principle possible to do with any position control method, but the specific properties of the SMA actuators, like the hysteresis, the first cycle effect and the long term changes, need to be taken into account. In this work, a wing profile prototype was measured using optical fiber sensors and traditional strain gauges. Also, external laser sensors were used to measure displacements of upper/lower surface and trailing edge. Shape change was obtained by embedding SMA wire actuators into fiber reinforced polymer (FRP) composite structure. SMA actuators were laminated in such way that bending of trailing edge is always downwards. Actuators are activated with Joule heating and the temperature is measured with integrated thermocouples and optical fiber temperature sensors. As a result, this work gave information about the usability of optical fibers sensors in active FRP composite structures. Measurements also give information about the efficiency of SMA actuators in shape control of relatively stiff FRP structures.
ABSTRACT:A large research program of digital product process has been active (2008)(2009)(2010)(2011)(2012) in Finland. The goal of the program has been to increase customer orientation and productivity in company networks that design and deliver products, systems and services to global markets. For small and medium sized companies the developing of multitechnical products usually has to be done in a network of companies. This requires a lot of data transfer and integration between various computer systems. To improve these processes the research project "Developing the digital product process of multitechnical products to improve the designing and manufacturing of small series product" (Monidigi) has been started.The aim of the Monidigi research was to improve the design process by using solely digital product information that is handled by proper product lifecycle management systems. The product development is guided by the philosophy of the digital prototype that is tested in a virtual working environment. Products are modeled in 3D and developed by various simulations and analyses before real prototypes are made. This allows a flexible design process and coordinated change management. Digital product processes allow easy data transfer, collaborated engineering and modern manufacturing in a network of companies. Several examples and development possibilities and the state of the art in construction industry are introduced and evaluated.
The objective of this study was to design a calibration phantom for a surgical navigator used in a hospital environment. It addresses two major issues: the design of an accuracy phantom and the accuracy analysis of the surgical navigator in a hospital setting. The designed phantom was used to assess the accuracy of the optical tracking modality of the surgical navigator used at Oulu University Hospital, Oulu, Finland. The phantom functioned according to the design criteria, it was easy to use and it had enough calibration points that were localized by the navigator according to the accuracy assessment protocol to assess the accuracy error. The distances measured from a fixed origin with the surgical navigator were compared to the known phantom calibration point coordinates. The mean error was within the manufacturer specifications of 1.00 mm. The analysis done using the designed phantom and accuracy assessment protocol showed that the error increased with the distance from the center of the phantom. The accuracy assessment protocol using the present phantom proved to be a suitable method for accuracy analysis of a surgical navigator in a hospital setting.
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