Aircraft design is an example of complex engineering where dimensioning tools can be valuable for the designers and decision makers in the early stage of the development process. These tools can be in form of a database over key numbers for different components or technologies. One of the critical parts of an aircraft is the actuator system. Conventional hydraulic actuators are demanding regarding maintenance which implies high operation costs. Therefore in recent years the focus has been set on electro-hydrostatic and electro-mechanical actuators. The aim of this work is to build a platform which can make it easier for designers and decision makers to analyze, compare and optimize different technologies regarding the actuator system. For this reason a simplified quasi-static actuator model, including reactive power consumption has been developed. This model makes it possible to reduce the complexity of the actuator models to such extent that the resulting computional tool can be used for studies of the system performance during entire flight missions and/or for optimization. Power density, cost and weight of the actuator systems are some of the important key numbers for comparing purpose and as a platform for the dimensioning of the aircraft. The ambition is then to build up a database of different actuator solutions with the key technical parameters mentioned above, that can be used in modeling and dimensioning of an aircraft. In order to avoid time consuming finite element calculations when analyzing an electrical machine a reluctance network model can be used. The basic idea of the proposed network model is to divide the rotor and the stator into a grid of small reluctance elements and provide those that correspond to the permanent magnet and the air gap between the magnets with time varying reluctances. The suggested computationally approach constitute a fast way to evaluate permanent magnet electrical machines with the respect to their performance. A preferred electrical machine provided with balance teeth and concentrated windings showed good electromechanical and thermal behavior. A balance tooth is a tooth without winding between each adjacent phases that has a cooling effect on the nearest windings, resulting in less copper losses. The balance teeth increases the voltage-time area, leading to higher induced voltage and higher torque production. Another advantage of the chosen design is its redundancy and fault tolerance capabilities. The machine comprises two independent half machines that also offers a high level of redundancy with two separate power channels. / QC 20100914

Currently the system development of aircraft engineering concentrates its focus on the reduction of energy consumption more than ever before. As a consequence, the efficiency of subsystems inside the aircraft is highlighted. According to previous investigations the simplification/unification of conventional multifaceted board energy systems by means of electric power management is the most promising way concerning aircraft global efficiency improvement. The main aim of the present work was to optimize a multi-device, heavy duty EHA-System by introducing of a comprehensive perspective. In order to achieve the final, non-plus-ultra improvement level, the attributes of architecture, hardware and operation method were combined in an interactive manner, whereas particular attention has been paid to the mutual enhancing influences. The maximum reduction of losses, the minimizing of consumption and weight optimization can be achieved concurrently when the physical coherences between the involved subsystems are understood and their hidden potentials are exploited. This can only be achieved in one way and the detail follows: The most effective way to reduce both manufacturing effort and weight is to introduce a multiple-allocation philosophy. The highest reliability possible can be achieved by novel cascade-nested system architecture and strict restraining of the control logic. By employing an ultra-low-loss hardware concept, the energy efficiency can be maximized at a necessary minimum own weight. Last but not least, possibly the most important cognition is that an intelligent operation method will improve the actual system and influence the entire system positively and with a lower effort. The final conclusion is that the only and reasonable way to achieve an ultimate optimized solution of an actuation system is an all-encompassing consideration. Eventually it was to recognize that the final result is nothing but ultimate lightweight architecture, i.e. a non-plus-ultra solution. / Gegenwärtig konzentriert sich die Technologieentwicklung für Flugzeuge auf die Reduktion des Energieverbrauchs mehr denn je zuvor. Hierfür ist die Effizienz der an Bord befindlichen, nicht propulsiven Subsysteme neben der Wirkungsgradverbesserung der Triebwerke von zentraler Bedeutung. Laut vorangegangenen Untersuchungen und Studien ist die Vereinfachung bzw. Vereinheitlichung der Vielfalt der konventionellen Bordenergiesysteme durch ein adäquates Energiemanagement unter Verwendung von Elektrizität der aussichtsreichte Weg zur Effizienzverbesserung auf der Gesamtflugzeugebene. Durch die Elektrifizierung wurden die einzelnen Geräte zwar zuverlässiger und energieeffizienter als je zuvor aber gleichzeitig erheblich schwerer, sodaß ein signifikanter Verlust an Nutzlasten auf Gesamtflugzeugebene hervorgerufen wird. Das Hauptziel der vorliegenden Arbeit war es, ein Schwerlast-EHA-System mit mehrfachen Betätigungseinheiten durch Einführung von umfassenden Perspektiven zu optimieren. Durch Einführung der sog. ganzheitlichen Leichtbauweise demonstriert die Arbeit, wie das Subsystem mit mehreren Endgeräten ultimativ optimiert werden kann, ohne Abstriche an Gewichtsbilanz u/o Kompromiß mit der Energieeffizienz zu machen. Um eine wahrhaftige Optimierung, d.h. die Erreichung des ultimativen, Nonplusultra-Verbesserungslevels zu erreichen, wurden die Systemarchitektur, die Hardware und die Operationsmethode interaktiv kombiniert, wobei die besondere Aufmerksamkeit auf die interaktiven, zur Verbesserung führenden Einflüsse gelegt wurde. Die Minimierung des Energieverbrauchs und die ultimative Gewichtsoptimierung gleichzeitig können erreicht werden, wenn die physikalischen Zusammenhänge zwischen den involvierten Subsystemen verstanden und ihre verborgenen Potentiale ausgenutzt werden. Der einzige und vernünftige Weg zur Erreichung der ultimativen Optimierung eines Betätigungssystems ist eine allumfassende Betrachtung, also eine ganzheitliche Betrachtungs- bzw. Vorgehensweise.