Over the past few years, electric propulsion systems have been widely used in automotive applications. The next decade is likely to see the electrification of aerial vehicles. In the past 20 years, the passengers demand in the aviation industry has increased by roughly 5% annually. Drastic increment in the passengers demand leads to many problems such as emission, noise pollution, airports capacity shortage, and high fuel consumption. An electric airplane that can take off and land in an extremely short runway can solve all the mentioned problems. Also, an airplane that is smaller and lighter with the ability to take off and land from an extremely short runway can be used as a new transportation system in congested cities and solve the urban road traffic and compensate for people’s time wasted in traffic. With this in mind, in this thesis, the feasibility of converting a conventional fixed-wing direct-drive propeller airplane to an electric extremely short takeoff and landing airplane has been examined. An overview of the history of electric aerial vehicles and flying cars is conducted where some of these vehicles are still under development phase. The main aim of this thesis is to address the effect of takeoff and landing runway length on the electric motor main specifications, including power, torque, and speed. Also, the effect of cruising speed on the motor specifications are investigated, and it is observed that there is a considerable difference between the amount of required power for the cruising mode and takeoff mode. In the end, the impact of the braking system and airplane weight on the landing distance are examined, and It is found that for an airplane with a cruise-efficient propeller, usage of thrust reverser is not practical and hence it is not recommended. Although if the propeller is designed to have high efficiency at takeoff and landing, the thrust reverser can be a good solution to make the landing runway shorter. / Thesis / Master of Applied Science (MASc)

Detta arbete har med hjälp av en antagen förbrukningsprofil för effekt samt energibehov för laddning av elflyg beräknat om det nuvarande elnätet på mellanspänningsnivå kommer att klara av en framtid där elflyg kommer att användas för kortare resor eller om det kommer behöva avhjälpas med ett batterilagringssystem. Arbetet kom fram till att oavsett räknad förbrukning kommer dagens elnät klara av detta vid normaldrift men inte vid reservdrift för de två fall med högre räknad förbrukning. Vidare kom arbetet fram till att vid användning av nuvarande nätstation kommer ett batterilagringssystem alltid att behövas både vid normaldrift och reservdrift. Arbetet kom även fram till att effekten som elflyg kommer att kräva för att ladda dessa är den begränsande faktorn för elnätet medan energin som dessa kräver för laddning under en hel dag inte är en begränsande faktor. / This work has, with the help of an assumed consumption profile for power and energy requirements for charging electric aircraft, calculated whether the current medium voltage power grid will be able to handle a future where electric aircraft will be used for shorter trips, or if it will need to be supplemented with a battery energy storage system. The work concluded that regardless of the calculated consumption, the current power grid will be able to handle this under normal operation but not under reserve operation for the two cases with higher calculated consumption. Furthermore, the work concluded that when using the current substation, a battery energy storage system will always be needed both under normal operation and reserve operation. The work also found that the power required to charge electric aircraft is the limiting factor for the power grid, while the energy they require for charging over a full day is not a limiting factor.

In this thesis the problem of autonomous landing of an unmanned aerial vehicle named AE-2 is addressed. The guidance and control technique is developed and demonstrated through numerical simulation results. The complete work includes Mathematical modeling, Control design, Guidance and State estimation for AE-2, which is a fixed wing vehicle with 2m wing span and 6kg weight. The aerodynamic data for AE-2 is available from static wind tunnel tests. Functional fit is done on the wind tunnel data with least squares method to find static aerodynamic coefficients. The aerodynamic forces and moment coefficients are highly nonlinear some of them are partitioned in two zones based on the angle of attack. The dynamic derivatives are found with Athena Vortex Lattice software. For the validation of vortex lattice method the static derivatives obtained by the wind tunnel tests and vortex lattice method, are compared before finding dynamic derivatives. The dynamics of the servo actuators for the aerodynamic control surfaces is incorporated in the simulation. The nonlinear dynamic inversion technique has been used for the guidance and control design. The control is structured in two loops, outer and inner loop. The goal of outer loop is to track the guidance commands of altitude, roll angle and yaw angle by converting them into body rate commands through dynamic inversion. The inner loop than tracks these commanded roll rate, pitch rate and yaw rate by finding the required deflection of control surfaces. The forward velocity of the vehicle is controlled by varying the throttle. A controller for actuator is also designed to reduce the lag. The guidance for landing consists of three phases approach, glideslope and flare. During approach the vehicle is aligned with the runway and guided to a specified height from where the glideslope can begin. The glideslope is straight line path specified by a flight path angle which is restricted between 3 to 4 degree. At the end of glideslope which is marked by flare altitude the flare maneuver begins which is an exponential curve. The problem of transition between the glideslope and flare has addressed by ensuring continuity and smoothness at transition. The exponential curve of flare is designed to end below the ground so that it intersects the ground at a prespecified point. The sink rate at touchdown is also controlled along with the location of touchdown point. The state estimation has been done with Extended Kalman Filter in continuous discrete formulation. The external disturbances like wind shear and wind gust are accounted by appending them in state variables. Further the control design with guidance is tested from various initial conditions, in presence of wind disturbances. The designed filter has also been tested for parameter uncertainty.