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A decomposition methodology based on the concept of "thermoeconomic isolation" applied to the synthesis/design and operational optimization of an advanced tactical fighter aircraft is the focus of this research. Conceptual, time, and physical decomposition were used to solve the system-level as well as unit-level optimization problems. The total system was decomposed into five sub-systems as follows: propulsion sub-system (PS), environmental control sub-system (ECS), fuel loop sub-system (FLS), vapor compressor and PAO loops sub-system (VC/PAOS), and airframe sub-system (AFS) of which the AFS is a non-energy based sub-system. Configurational optimization was applied. Thus, a number of different configurations for each sub-system were considered. The most promising set of candidate configurations, based on both an energy integration analysis and aerodynamic performance, were developed and detailed thermodynamic, geometric, physical, and aerodynamic models at both design and off-design were formulated and implemented. A decomposition strategy called Iterative Local-Global Optimization (ILGO) developed by Muñoz and von Spakovsky was then applied to the synthesis/design and operational optimization of the advanced tactical fighter aircraft. This decomposition strategy is the first to successfully closely approach the theoretical condition of "thermoeconomic isolation" when applied to highly complex, highly dynamic non-linear systems. This contrasts with past attempts to approach this condition, all of which were applied to very simple systems under very special and restricted conditions such as those requiring linearity in the models and strictly local decision variables. This is a major advance in decomposition and has now been successfully applied to a number of highly complex and dynamic transportation and stationary systems. This thesis work presents the detailed results from one such application, which additionally considers a non-energy based sub-system (AFS). / Master of Science

Adaptive control designs using neural networks (NNs) based on dynamic inversion are investigated for aerospace vehicles which are operated at highly nonlinear dynamic regimes. NNs play a key role as the principal element of adaptation to approximately cancel the effect of inversion error, which subsequently improves robustness to parametric uncertainty and unmodeled dynamics in nonlinear regimes. An adaptive control scheme previously named composite model reference adaptive control is further developed so that it can be applied to multi-input multi-output output feedback dynamic inversion. It can have adaptive elements in both the dynamic compensator (linear controller) part and/or in the conventional adaptive controller part, also utilizing state estimation information for NN adaptation. This methodology has more flexibility and thus hopefully greater potential than conventional adaptive designs for adaptive flight control in highly nonlinear flight regimes. The stability of the control system is proved through Lyapunov theorems, and validated with simulations. The control designs in this thesis also include the use of pseudo-control hedging techniques which are introduced to prevent the NNs from attempting to adapt to various actuation nonlinearities such as actuator position and rate saturations. Control allocation is introduced for the case of redundant control effectors including thrust vectoring nozzles. A thorough comparison study of conventional and NN-based adaptive designs for a system under a limit cycle, wing-rock, is included in this research, and the NN-based adaptive control designs demonstrate their performances for two highly maneuverable aerial vehicles, NASA F-15 ACTIVE and FQM-117B unmanned aerial vehicle (UAV), operated under various nonlinearities and uncertainties.

This thesis deals with the design of an anti-skid brake controller for a generic fighter aircraft. Antiskid brake controllers prevent wheel locking and maximize the coefficient of friction between the tyre and the ground, resulting in lower stopping distance and time. The frictional force is maximized by regulating the slip. A model for the landing gear is first developed, which consists of the translational and rotational motions of the wheel, the equation for the slip and the elastic landing gear strut dynamics. The elastic behaviour of the landing gear is characterized through its modal frequencies, obtained from a Finite element analysis. As the governing equations are nonlinear, with linear elastic deformations of the strut, feedback linearization is used to design the anti-skid controller. The brake controller is found to work well. Its stability is verified through numerical simulations. Both the plant parameters and the sensor measurements are perturbed up to 10% from their nominal values. It is seen that the feedback linearization tolerates these variations quite well. The system is exceptionally tolerant to sensor noises. The torsional stiffness of the strut is found to be more critical than the longitudinal stiffness. Limits on the torsional stiffness that can be tolerated by the controller are found. This determines the limits on the stiffness of the landing gear beyond which gear walk may appear. The thesis concludes with suggestions for future work in this exciting field.

Assignment (MComm)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The recent procurement of modern fourth-generation fighter aircraft by the South African Air Force (SAAF), severe budget constraints, as well as demographic transformation of the South African National Defence Force (SANDF) impacted heavily on the selection and training of SAAF pilots. Against this backdrop, this predictive criterion-related validation study attempted to find an optimal battery to predict various aspects of pilot training performance, using all SAAF qualified pilots from 1997 to 2002 as the sample (N=107). Multiple regression analyses were performed to construct a model which can be used to predict the success of trainee pilots in three phases of pilot training, namely officers' formative training, ground school training and practical flight training. Stepwise regression analyses with training grade achieved as criterion were performed on the data for each of the phases of training. Multiple correlations of 0,34 (p<0,001), 0,21 (p>0,05) and 0,22 (p<0,05) were obtained for flight, ground school and formative training results respectively. Various recommendations regarding the present composition of the battery are made / AFRIKAANSE OPSOMMING: Die onlangse aanskaffing van moderne vierde-generasie vegvliegtuie deur die Suid Afrikaanse Lugmag (SALM), sowel as omvattende begrotingsbeperkinge en die demografiese transformasie van die Suid-Afrikaanse Nasionale Weermag (SANW) het In swaar impak op die keuring en opleiding van SALM vlieëniers gehad. Teen hierdie agtergrond het hierdie voorspellende kriteriumgerigte valideringsstudie gepoog om In battery saam te stel wat die verskeie aspekte van prestasie tydens vlieëniersopleiding optimaal kon voorspel. AI die SALM vlieëniers wat gekwalifiseer het van 1997 tot 2002 is in die steekproef ingesluit (N=107). Meervoudige regressieontledings is uitgevoer om In model te bou wat die sukses van kandidaatvlieëniers kon voorspel tydens die drie fases van opleiding, naamlik offisiersvorming, grondskool en praktiese vliegopleiding. Stapsgewyse regressie-ontleding is gedoen vir elke fase van opleiding, met opleidingspunt behaal as kriterium in elke fase. Meervoudige korrelasies van 0,34 (p<0,001), 0,21 (p>0,05) en 0,22 (p<0,05) is verkry vir vlieg-, grondskool-, en vormingsopleidingspunt onderskeidelik. Verskeie aanbevelings in verband met die samestelling van die battery word gemaak.

As experienced fighter pilots leave the United States Air Force (USAF) and Royal Australian Air Force (RAAF), there is a need to develop new competent pilots to meet national defense requirements. Fighter training programs are expensive for taxpayers, and the USAF and RAAF face significant resource problems developing and implementing these programs. Using policy feedback theory and punctuated equilibrium theory as the theoretical foundation, the purpose of this comparative, multi-case study of current USAF F-16 and RAAF F-18 fighter pilot training policies was to inform training policy development and efficacy of future USAF and RAAF fighter pilot training programs. Data were gathered from training policy documents and 12 interviews with F-16 and F-18 pilots. Data were deductively coded and analyzed using policy feedback and punctuated event themes. Findings indicate that policy feedbacks and punctuated events influence fighter pilot training policy. Best practices for training include optimum stress management, appropriate academic course timing, and phase-based training techniques. Optimal instructional approaches included a servant leadership philosophy and a need for improved kinesthetic flight preparation tools and procedures. The USAF and RAAF approach fighter pilot training differently. The positive social change implications stemming from this study include recommendations to the USAF and RAAF that may improve fighter pilot training policy at the lowest possible cost to the taxpayers.

<p>Försvarsmakten har skapat en doktrinhierarki där det redovisas hur Försvarsmakten konceptuellt skall genomföra insatser. Doktrin för luftoperationer är den del av doktrinen som specifikt riktar sig mot flygstridskrafter. I dagens insatsförsvar är tänkbara insatser väsensskilda från invasionsförsvarets insatser, och för detta har en ny typ av förband skapats, insatsförbandet. Flygstridskrafterna bidrar med bland annat Stridsflygenhet (SE), en insatsdivision utrustad med JAS 39. I denna uppsats avser jag undersöka huruvida doktrinen erbjuder stöd, konceptuellt eller praktiskt, till ledningen för en enhet av det ovan nämnda slaget. Jag har genom litteraturstudie tagit fram på vilket sätt DLuftO anger att flygstridskrafter skall nyttjas. Jag har intervjuat ledningen på SE 01 och SE 02 för att undersöka doktrinens roll i verksamheten. Därefter har jag genomfört en komparativ analys mellan verkligheten och doktrinen. Genom analysen har jag kunnat dra slutsatsen att DLuftO till begränsad del erbjuder stöd för divisionsledning i det moderna insatsförsvaret.</p> / <p>The Swedish armed forces has created a doctrine which, on a conceptual level, regulates how the Armed Forces carry out operations. “Doctrine for air operations” (DLuftO) is Air Force specific and forms apart of the overall doctrine of the Swedish Armed Forces. In the Swedish Air Force the focus has shifted from national defence to international operations. This has created new tasks and demands, which has led to the creation of a new type of unit. This unit will have to be prepared to meet the demands of a combined mission in international operations. One of these units is the SE unit (SE =Fighter Unit), a JAS 39 squadron with air-to-air, air-to-ground and reconnaissance capabilities. In this essay, I intend to investigate whether the doctrine offers support, conceptually or practically, to the commanding officers of a fighter unit of this kind. I have investigated in what way DLuftO dictates how air power is intended to be used. I have interviewed commanding officers on SE 01 and SE 02 to investigate how the doctrine is used. This has then formed the basis for a comparative analysis between reality and the doctrine. I have been able to conclude that DLuftO offers a limited amount of support for commanding officers on a fighter squadron in a combined military operation.</p>

<p>1946 infördes en ny befattning i flygvapnet – Fältflygare. Dessa korttidsanställda piloter utbildades fram till och med 1982, året innan den Nya Befälsordningen infördes i försvarsmakten vilken innefattade alla officerare i en och samma kategori – yrkesofficerare. År 2008 reviderades dock befälsordningen, och sedan dess delas försvarsmaktens officerare in i två kategorier: specialistofficer respektive officer. Blivande stridspiloter rekryteras idag till den senare kategorin och anställs som officerare. Denna uppsats syftar till att belysa de argument som var bidragande till införandet av fältflygare och testa dessas validitet som argument för en applicering av tvåbefälssystemet på flygvapnets piloter idag. Uppsatsen utreder fältflygarsystemets framväxt, utformning, genomförande och avslutande samt jämför förutsättningarna mellan 1946 och 2010 inom områdena säkerhetspolitik, uppgifter samt ekonomi. Dessutom jämförs det svenska flygvapnets personalfördelning med ett antal andra länder. Genom att sätta de funna argumenten i dagens kontext, försöker validiteten av dessa avgöras. Uppsatsen avslutas med en diskussion rörande resultatet samt behovet av framtida forskning inom området. Resultatet i uppsatsen pekar på ett antal huvudsakliga argument för införandet av fältflygarsystemet, vilka samtliga kan härledas till flygvapnets expansiva fas under 30- och 40-talet. Uppsatsen visar att inget av dem är giltigt som ett argument för ett införande av ett tvåbefälssystem för flygvapnets piloter idag. Detta är främst på grund av skillnader mellan 1946 och idag rörande den säkerhetspolitiska situationen samt flygvapnets uppgifter. Det huvudsakliga syftet med fältflygarsystemet, att rekrytera en stor mängd individer till ett flygvapen under uppbyggnad, speglar inte dagens situation. Vidare är försvarsmaktens uppgifter idag betydligt fler än de som fältflygarna utbildades för att lösa: försvar av landet i händelse av krig.</p> / <p>In 1946, the Swedish Air Force (SwAF) introduced a new position open for pilot applicants. These pilots were trained and hired as non-commissioned officers and served in during a limited period of time. Influenced by the British RAF system with short service personnel, this system was in use until 1982. That year, it was decided that the Swedish Armed Forces would consist only of commissioned officers. However, in 2008, the non-commissioned officers were re-introduced into service. Today, the officers of the Armed Forces serve either as non-commissioned officers (“specialistofficerare) or commissioned officers (“officerare”). Aspirants who are applying to figher pilot training within the SwAF go through a three-year-long academic education in order to become commissioned officers. This essay aims to elucidate the key arguments used to introduce the system of non-commissioned fighter pilot officers and to test the validity of these arguments for applying the “new” system of officer ranks/other. The essay investigates the evolution, shaping, implementation and termination of the Fältflygare-system. It also compares 1946 and 2010 on three different aspects: the air force’s economic situation and tasks as well as the security policy-situation of the country. Also, a comparison of how officers are organised is made, between the SwAF and the air force of five other countries. The end of the essay consists of a discussion of the results. The result of the essay shows that none of the previous arguments are valid for implementing a system of non-commissioned fighter pilot officers for the SwAF pilots today. The main reasons for this are major differences in the tasks given to the armed forces and the differences of the security policy-situation. The main purpose of the Fältflygare-system, to recruit and train a large quantity of pilots for an air force that was being developed, does not reflect the situation today. Furthermore, the armed forces and air force today must be ready to solve a wider range of tasks today than before, particularly when it comes to peace keeping and peace enforcement missions. The older system trained for a more specific task - defending the Swedish country’s borders in case of a war between NATO and the Warsaw Pact.</p>

Försvarsmakten har skapat en doktrinhierarki där det redovisas hur Försvarsmakten konceptuellt skall genomföra insatser. Doktrin för luftoperationer är den del av doktrinen som specifikt riktar sig mot flygstridskrafter. I dagens insatsförsvar är tänkbara insatser väsensskilda från invasionsförsvarets insatser, och för detta har en ny typ av förband skapats, insatsförbandet. Flygstridskrafterna bidrar med bland annat Stridsflygenhet (SE), en insatsdivision utrustad med JAS 39. I denna uppsats avser jag undersöka huruvida doktrinen erbjuder stöd, konceptuellt eller praktiskt, till ledningen för en enhet av det ovan nämnda slaget. Jag har genom litteraturstudie tagit fram på vilket sätt DLuftO anger att flygstridskrafter skall nyttjas. Jag har intervjuat ledningen på SE 01 och SE 02 för att undersöka doktrinens roll i verksamheten. Därefter har jag genomfört en komparativ analys mellan verkligheten och doktrinen. Genom analysen har jag kunnat dra slutsatsen att DLuftO till begränsad del erbjuder stöd för divisionsledning i det moderna insatsförsvaret. / The Swedish armed forces has created a doctrine which, on a conceptual level, regulates how the Armed Forces carry out operations. “Doctrine for air operations” (DLuftO) is Air Force specific and forms apart of the overall doctrine of the Swedish Armed Forces. In the Swedish Air Force the focus has shifted from national defence to international operations. This has created new tasks and demands, which has led to the creation of a new type of unit. This unit will have to be prepared to meet the demands of a combined mission in international operations. One of these units is the SE unit (SE =Fighter Unit), a JAS 39 squadron with air-to-air, air-to-ground and reconnaissance capabilities. In this essay, I intend to investigate whether the doctrine offers support, conceptually or practically, to the commanding officers of a fighter unit of this kind. I have investigated in what way DLuftO dictates how air power is intended to be used. I have interviewed commanding officers on SE 01 and SE 02 to investigate how the doctrine is used. This has then formed the basis for a comparative analysis between reality and the doctrine. I have been able to conclude that DLuftO offers a limited amount of support for commanding officers on a fighter squadron in a combined military operation.