The flight control actuation system is one of the most critical systems in an aircraft. A failure of this system cannot occur, since it would have catastrophic consequences. The environment it operates in is considered as highly demanding, with temperatures ranging from -50 to +60 degrees Celsius, speeds from 0 to Mach 2+ and G-forces from -3 up to 9. At the same time, the system shall be as small and lightweight as possible, since every gram and cm 3 will decrease the available payload and/or increase the total aircraft size, which in turn increase the fuel-burn. The preferred choice of technology for actuators has, since the late 1930s, been hydraulics. Hydraulic actuators are characterized by high power density, high technical maturity, high safety, and high response. With emerging benefits from the electric domain, research during the last decade has been focusing on electrified alternatives as the future alternative for actuators.First of all, I would like to thank my main supervisor, Professor Petter Krus. Thank you for being a source of inspiration, and for your guidance within the academic world. I also want to express my deepest gratitude to my co-supervisor, Dr. Alessandro Dell'Amico. Thank you for believing in me, for your great dedication, for all your support and for pushing me to always improve.I also would like to thank my former and current managers, Niklas Fält, Marina Wallin, Dr. Klara Grönhagen and Andreas Albrektsson. Thank you for your trust, support and for helping me keeping a good balance in between academic-and industrial work. Thank you to all my colleagues at Saab for being curious about my work, for your patience and for all your support. I also want to thank all colleges at FLUMES for your guidance, all great chats and memories from this journey. A special thank you to Christopher Reichenwallner, who has walked this journey beside me. Thank you for all therapeutic sessions, jokes and late nights of work together.Finally I want to thank my family and friends. Thank you for all support. And to my fiancee Frida, thank you for your endless support, your patience, your help in finding balance in life and your ability to always know what I need.

This paper illustrates how a Singular Value Decomposition (SVD) and regression analyses can be used to create estimation models for aircraft actuator components by use of industrial data. The estimation models are at the end used to show how an electromechanical actuator´s weight and size will evolve with respect to output force. An essential step in the early design of aircraft is to be able to predict the weight and size of a resulting concept. This weight and size typically include contributions of main components such as wing and fuselage. Weight and size estimations at this stage can also range down to components at a sub-system level, for example, the aircraft actuators. The weight and size of an actuator depends on many parameters, and it is desirable to understand any underlying relationship to make qualified estimations of an actuator’s characteristics. However, the knowledge about a design is often limited at an early design stage and the required information is not always available. Consequently, estimations must be made from limited information and desired properties of the actuator. One way to approach this problem is to use SVD. An SVD analysis determines the most influential parameters in a data set and uses these to create an estimation model that only requires a few inputs for estimating the remaining parameters in the data set. An SVD can thereby be used for both identifying the driving parameters in a statistical dataset of existing solutions and to estimate the characteristics of new designs to be developed.

We claim that a notion of rhetic acts can fulfil a useful function in speech act theory. Austin’s examples of rhetic acts are saying that something is so and so, telling someone to do something, and asking whether something is so or so. Though this certainly sounds as if he is talking about the illocutionary acts of asserting, giving directions, and asking questions, we explain why the acts Austin mentions are not illocutionary after all. In short, illocutionary acts are acts that commit the participants in a conversation to various things. The illocutionary force of an utterance is determined by what it commits the interlocutors to. Our suggestion is that what looks like illocutionary force in the cases mentioned by Austin is really the contributions grammatical moods make to the literal meaning of utterances. We argue that this contribution is not part of what characterizes illocutionary acts as such. The semantic contribution of mood already characterizes those speech acts that Austin uses to exemplify rhetic acts. These rhetic acts are not committing in the way that illocutionary acts essentially are. So there must be a sense in which such rhetic acts are not illocutionary ones. In the final section, we suggest that the varieties of rhetic acts indicated by Austin fit neatly into a standard linguistic theoretical framework of conversational scoreboards.