Design and Control of an Experimental Tilt-Wing Aircraft

In this project, work has been done in the field of conceptual design of experimental tiltrotors. The main tools that have been used are NDARC (NASA Design and Analysis of Rotorcraft) and SIMPLI-FLYD. NDARC is a conceptual design tool for rotorcraft, and it is used to find trim points under various flight conditions. SIMPLI-FLYD is an integrated collection of software tools that enables a flight dynamics and control assessment of the rotorcraft vehicle design generated from NDARC. Two different tiltrotors have been investigated. Initially, work was done with the Bell XV- 15 tiltrotor. NDARCs ability to correctly model the tiltwing transition between airplane mode and hover mode was looked into. In addition, data from old flight tests were compared to the NDARC output, to see how accurately performance could be predicted. After the XV-15 analysis, an NDRARC model of a novel tiltwing concept from Elytron Aircraft was written and analyzed together with SIMPLI-FLYD. Elytron 2S is an experimental tiltwing aircraft, consisting of a joined-wing design with a small central wing for the proprotor. An alternative approach to hover control is used, where the typical rotor hub and swash plate are substituted for linear actuators controlling pitch, yaw and roll. The objective with the analysis of Elytron is to obtain a more complete understanding of the maneuverability and possible performance of this alternative aircraft configuration

Aerodynamic Analysis of the Elytron 2S Experimental Tiltwing Aircraft

The Elytron 2S is a prototype aircraft concept to allow VTOL capabilities together with fixed wing aircraft performance. It has a box wing design with a centrally mounted tilt-wing supporting two rotors. This paper explores the aerodynamic characteristics of the aircraft using computational fluid dynamics in hover and low speed forward flight, as well as analyzing the unique control system in place for hover. The results are then used to build an input set for NASA Design and Analysis if Rotorcraft software allowing trim and flight stability and control estimations to be made with SIMPLIFLYD

Vegetable production on Gotland, Sweden : possibilities for development and growth

A diet based on a bigger part of locally produced vegetables can contribute to decreasing environmental impact and improved health. In Gotland horticulture has increased more than in Sweden in total during the last 15 years. To investigate possibilities for development of Gotland´s horticulture, the cultivation of potato, vegetables, fruits and berries was mapped through a questionnaire among growers. Interviews and a workshop with growers and reseller were conducted to investigate the interest and prerequisites for growing new crops. In total approximately 2340 hectares of potato, vegetables, fruits and berries were grown in Gotland in 2012. The four most commonly grown crops were potato, carrot, parsnip, and beetroot, which together stood for 88 per cent of the total area in this study. There is a widespread interest for new vegetables among both growers and resellers who came up with many suggestions for future crops. For example there is an increasing demand for baby leaf salad, beans, bundles of early root vegetables, shoots and sprouts, asparagus, tomato and herbs. There is also a demand for more onion, carrot, cauliflower, broccoli and lettuce. Both growers and resellers saw a lack of communication between them. To communicate what the consumers demand, growers and resellers should try to find more ways to communicate. Selling products locally e.g. through a farm shop gives the growers a possibility to get feedback on their products, which can be used to find the right quality and to get new ideas. To succeed with new crops both the right cultivation conditions and a customer base are required. Starting with a small trial cultivation is a good way to learn how to grow them. When a new crop I grown in bigger scale it is good to have an economical buffer. The growers signal that there is a lack of advisory for horticulturists in Gotland. To be able to compete with growers in other parts of Sweden and abroad advisory in horticulture should be started up on the island. Advisory on both economy and cultivation techniques is needed. Economic calculations for more vegetables would facilitate for growers who want to grow new crops.En ökad andel lokalproducerade grönsaker i kosten kan bidra till minskad miljöpåverkan och bättre hälsa. På Gotland har odlingen av trädgårdsgrödor ökat mer än i Sverige som helhet den senaste femtonårsperioden. För att undersöka möjligheter till utveckling för Gotlands trädgårdsnäring kartlades öns odling av potatis, rotfrukter, grönsaker, frukt och bär genom en enkätstudie riktad till odlare. Intervjuer och workshop med odlare och återförsäljare genomfördes för att undersöka intresse och förutsättningar för att odla nya grödor. Totalt odlades cirka 2340 hektar potatis, rotfrukter, grönsaker, frukt och bär på Gotland år 2012. De fyra mest odlade grödorna i studien var potatis, morot, palsternacka och rödbeta, som tillsammans utgjorde 88 procent av den totala arealen i studien. Det finns ett utbrett intresse för nya grönsaker både bland odlare och återförsäljare. Många förslag på framtidsgrödor finns hos odlare och återförsäljare. Bland annat finns ökad efterfrågan på baby leaf (småblad) sallad, bönor, tidiga rotfrukter i knippen, skott och groddar, sparris, tomat och örter. Det finns även utrymme för att odla mer av lök, morötter, rotselleri, blomkål, broccoli och sallad. Både odlare och återförsäljare tyckte att det fanns brister i kommunikationen dem emellan. För att förmedla vilka produkter konsumenterna efterfrågar borde odlare och grossister hitta fler mötesplatser där de kan kommunicera. Att sälja produkter lokalt, exempelvis genom gårdsbutik ger odlaren möjlighet att få direkt respons på sina produkter, vilket kan utnyttjas för att ta fram rätt kvalité och även för att få nya idéer. För att lyckas med att odla nya grödor krävs både lämpliga odlingsbetingelser och ett kundunderlag. Att testodla nya grödor i liten skala kan vara bra för att lära sig odla dem. När en ny gröda börjar odlas i större skala är det bra att ha en ekonomisk buffert som kan täcka upp för misstag. Odlarna signalerar att det är brist på rådgivning inom trädgårdsnäringen på Gotland. För att kunna konkurrera mot odlare i övriga Sverige och utomlands bör rådgivning för trädgårdsnäringen startas upp på ön. Både odlingsteknisk och ekonomisk rådgivning behövs. Sammanställande av kalkyler för fler grönsaker skulle underlätta för odlare som vill börja odla nya grödor

Cooperative Control for Landing a Fixed-Wing Unmanned Aerial Vehicle on a Ground Vehicle

High Altitude Long Endurance (HALE) platforms are a type of Unmanned Aerial Vehicle (UAV). With their relatively easy deployment and independence of a fixed orbit, HALE UAVs have the potential to replace satellites for certain Tasks in the future. A challenge with this technology is that the current platforms are too heavy to fly for a long period of time. A suggested method for reducing the weight is to remove the landing gear to instead use alternative methods for take-off and landing. One such alternative method is to land the UAV on top of a cooperating ground vehicle. In this thesis, the cooperative controller and the experimental setup of such a landing have been investigated. The cooperation between the systems was analyzed and evaluated analytically, through simulations and with flight tests. Using a PID controller for the position alignment and a modified flare law for the descent, feasibility of the landing was verified by performing a landing of a Penguin BE fixed-wing UAV on top of a cooperating ground vehicle

Modelling of glucose repression signalling in yeast Saccharomyces cerevisiae

Saccharomyces cerevisiae has a sophisticated signalling system that plays a crucial role in cellular adaptation to changing environments. The SNF1 pathway regulates energy homeostasis upon glucose derepression; hence, it plays an important role in various processes, such as metabolism, cell cycle and autophagy. To unravel its behaviour, SNF1 signalling has been extensively studied. However, the pathway components are strongly interconnected and inconstant; therefore, elucidating its dynamic behaviour based on experimental data only is challenging. To tackle this complexity, systems biology approaches have been successfully employed. This review summarizes the progress, advantages and disadvantages of the available mathematical modelling frameworks covering Boolean, dynamic kinetic, single-cell models, which have been used to study processes and phenomena ranging from crosstalks to sources of cell-to-cell variability in the context of SNF1 signalling. Based on the lessons from existing models, we further discuss how to develop a consensus dynamic mechanistic model of the entire SNF1 pathway that can provide novel insights into the dynamics of nutrient signalling

Struktur och kultur gör en ny organisation levande - en fallstudie om hur organisationsstruktur och organisationskultur ter sig i en ny multiarena i södra Sverige

Syftet med denna uppsats är att undersöka hur en ny organisation tar form. Uppsatsen kommer att behandla de centrala faktorerna; struktur och kultur, och hur de kan påverkas genom medarbetarskap. Fokus läggs på processen att forma en ny organisation och vilken funktion de två faktorerna har i de inledande faserna av en organisations livcykel. Frågeställningarna är vilken betydelse får faktorerna struktur och kultur för processen att forma en ny organisation och hur påverkar medarbetarskap faktorerna struktur och kultur? Det är en kvalitativ studie med abduktivt förhållningsätt där empiriinsamlingen har skett genom sju semistrukturerade djupintervjuer med respondenter med olika kopplingar till fallstudien. Det har även utförts en deltagande observation under ett personalmöte. Slutsatserna blev att en ny organisation går igenom olika faser under dess första tid. Dessa faser är kopplade till organisationslivcykeln som skapar olika förutsättningar för organisationen gällande struktur och kultur. Struktur och kultur är två faktorer som skapas och anpassas av medarbetarna och har möjlighet att stärka en ny organisation. Ett utökat arbete kring medarbetarskap där relationen mellan ledaren och medarbetaren är i fokus kan vara ett verktyg för att bygga en hälsosam struktur och kultur i en organisation

Djur i vården- En litteraturstudie om hur djur kan påverka den äldre människan för att uppnå välbefinnande

Normalt åldrande kan innebära att den äldre människan drabbas av ohälsa som kan leda till minskat välbefinnande. Djur kan ha ett vårdande syfte och används på följande sätt: Animal-assisted activity (AAA), animal-assisted therapy (AAT), animal-assisted intervention (AAI). Studiens syfte var att beskriva hur interaktion med djur kan användas som en omvårdnadsåtgärd för att den äldre människan inom vården ska uppnå välbefinnande. En frågeställning formulerades om vilka effekter djur kan ge. En litteraturstudie baserad på åtta kvantitativa samt två kvalitativa artiklar analyserades enligt en integrerad analys. I resultatet formulerades teman samt underteman (inom parentes): Depressiva symtom (ångest), upplevelser och känslor (ensamhet, stress, livskvalité, positiva känslor), minne, beteende (agitation och aggressivitet, socialt beteende). Djur i vården kan bidra till ett ökat välbefinnande för den äldre människan genom de positiva effekter som uppstår vid interaktionen

Intercropping strategies and challenges in cacao production : a field study in Juanjuí, Peru

In the region of San Martín, Peru, deforestation has led to a loss of biodiversity and agro-diversity. Furthermore, coca cultivation was common in the area a few years back. The Peruvian government has promoted cacao as an alternative crop to coca, which has led to an intensification of the cultivation of cacao and to cacao being the most economically important crop today in the area of Juanjuí, San Martín. Therefore, the aims of this study have been to: (1) study in which ways cacao is being cultivated in the area of Juanjuí, (2) find out for what purposes the farmers intercrop their cacao, (3) find out what challenges cacao farmers are facing, (4) look into how the farmers handle these challenges, and (5) explore if there are any differences between organically certified farmers and farmers without organic certification. Interviews and Participatory Rural Appraisal techniques with cacao farmers and key persons at the cacao cooperative ACOPAGRO, in Juanjuí, were conducted in order to answer the aims. The results showed that all of the farmers had planted shade trees in their cacao fields. Shade was also the most common reason to have other trees intercropped with cacao. However, most of the farmers also intercropped with trees for other purposes such as fertilizing effect, to restore the environment and to get wood and fruit for their families. Many different fruit- and timber tree species were used but some were more common than others, e.g. guaba, teak and mahogany. Many of the farmers also grew non-woody crops in their cacao fields, plantain/banana being the most common one. The main difference between newly established cacao fields and cacao fields in production was the occurrence of non-woody crops, which was higher in the newly established fields. Almost half of the species were grown systematically in the fields. The challenges that the farmers mentioned were lack of financial resources, uneven precipitation distribution, pests and diseases of cacao, transportation issues, lack of labourers and lack of knowledge about cacao cultivation techniques. The farmers had become members of ACOPAGRO to get access to credits and to achieve a higher price for their cacao. The droughts were handled by replacing dead plants and one of the farmers had bought irrigation systems. The farmers took several means against erosion and the fungal diseases and the pests were combated through both preventive methods and symptom treating methods. The lack of labourers for the harvest was handled through hiring day labourers and participating in the traditional labour-exchange system. There were two challenges that the farmers had not found any solutions to; how to handle flooding and how to solve the transportation issue. The organically certified farmers got higher yields and a higher cacao price than the non-certified farmers. The organically certified farmers also bought more inputs and came up with more solutions to the challenges. There were two main factors that seemed to influence the cropping systems on farm level: the crops used for intercropping contributed to increase the cacao yield or gave the farmers extra income or products for own use. ACOPAGRO most likely influenced the cropping systems since they distribute trees and give advice on managing cacao. The farmers had a good idea of how to handle the challenges connected to cacao production. In many cases lack of financial resources limited the way of handling the challenges. With more financial resources the farmers could invest in more technique and inputs. This would in turn enhance the farmers' working conditions and increase the cacao yield.En la región de San Martin, Peru, la deforestación ha conducido a una pérdida de la biodiversidad así como de la diversidad agrícola. Además, el cultivo de coca era muy común en esta área algunos años atrás. El gobierno peruano ha promovido el cacao como una alternativa al cultivo de la coca, lo que ha conducido a una intensificación del cultivo de cacao hasta el punto de convertirlo en el cultivo de mayor importancia económica en el área de Juanjuì, San Martín. Es por eso que los objetivos de este estudio ha sido: (1) estudiar de qué manera el cacao es cultivado en el área de Juanjuì, (2) encontrar las razones por las que los agricultores intercalan sus cultivos de cacao, (3) encontrar cuales son los desafíos que enfrentan los agricultores de cacao, (4) observar como los agricultores afrontan y manejan estos desafíos, y (5) explorar si existen algunas diferencias entre los agricultores con certificación de producción orgánica y aquellos que no cuentan con esta. Entrevistas y técnicas de valoración rural participativa con los agricultores de cacao y con personajes clave en la cooperativa de cacao ACOPAGRO, en Juanjuí, fueron implementadas para dar respuesta a estas interrogantes. Los resultados del estudio muestran que todos los agricultores tenían árboles de sombra en sus plantaciones de cacao. La obtención de sombra también fue la razón más común para tener árboles intercalados con el cacao. Sin embargo, la mayoría de los agricultores también intercalaron el cacao con los árboles para otros fines como la fertilización, la restauración del medio ambiente y para la obtención de madera y fruta para sus familias. Se utilizaron muchas especies de árboles diferentes, pero algunos árboles, tales como la guaba, la teca y la caoba, fueron más comunes que otros. Muchos de los agricultores también cultivaron otras especies no leñosas en sus plantaciones de cacao, siendo el plátano el más común. La principal diferencia entre las parcelas de cacao en crecimiento y las parcelas de cacao en producción fue la aparición de los cultivos no leñosos que fue mayor en las parcelas en crecimiento. Casi la mitad de las especies se cultivaron de forma sistemática en las parcelas. Los desafíos que los agricultores mencionaron fueron la falta de recursos económicos, la distribución desigual de las precipitaciones, las plagas y enfermedades del cacao, los problemas de transporte, la falta de mano de obra y la falta de conocimiento sobre las técnicas de cultivo del cacao. Los agricultores se habían convertido en miembros de ACOPAGRO para tener acceso a créditos y lograr un mayor precio por su cacao. Las sequías se hicieron frente con la sustitución de las plantas muertas, y uno de los agricultores habían comprado sistemas de riego. Los agricultores tomaron varias medidas contra la erosión. Las enfermedades causadas por hongos y plagas fueron combatidas mediante métodos de prevención y el tratamiento de síntomas. La falta de obreros para la cosecha se manejó a través de la contratación de jornaleros y mediante la participación en el sistema tradicional de intercambio de trabajo. Los agricultores con certificación orgánica obtenían un mayor rendimiento y un mayor precio por el cacao que los agricultores sin certificación. Los agricultores con certificación orgánica también pudieron realizar más inversiones y pensaron en más soluciones a los desafíos. Fueron principalmente dos factores los que influenciaron los sistemas de cultivo en nivel de la granja: los cultivos utilizados para intercalarse contribuyeron al incrementar los rendimientos del cacao o para dar un ingreso adicional a los agricultores o bien para proveer productos de autoconsumo. ACOPAGRO probablemente influyo fundamentalmente los sistemas de cultivo dado que distribuyeron arboles y proporcionaron consejos sobre el manejo del cacao. Los agricultores de cacao tenían una buena idea de cómo manejar los desafíos relacionados con la producción de cacao. En muchos de los casos la carencia de recursos financieros limitaba la manera en la cual los desafíos eran afrontados. Con más recursos financieros los agricultores podrían invertir en más tecnología e insumos. Esto a su vez conduciría a una mejora de las condiciones de trabajo de los agricultores y a un incremento de los rendimientos del cultivo de cacao

Aperiodic Communication for MPC in Autonomous Cooperative Landing

In this paper, we focus on the rendezvous problem for the autonomous cooperative landing of an unmanned aerial vehicle (UAV) on an unmanned surface vehicle (USV). These heterogeneous agents with nonlinear dynamics are dynamically decoupled but share a common cooperative rendezvous task. The underlying control scheme is based on the Distributed Model Predictive Control (MPC). One of our main contributions is a rendezvous algorithm with an online update rule of the rendezvous location. The algorithm requires that agents update the rendezvous location only when they are not guaranteed to reach it. Therefore, the exchange of information occurs aperiodically and proposed algorithm improves the communication efficiency. Furthermore, we prove the recursive feasibility of the algorithm. The simulation results show the effectiveness of our algorithm applied to the problem of autonomous cooperative landing.Comment: 7 pages, 6 figures, This work has been submitted to IFAC for possible publication, 7th IFAC Conference on Nonlinear Model Predictive Control 202