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The Unmanned Aerial Vehicles (UAVs) have become more popular and functional for today's needs in comparison to the conventional aircrafts for military, agriculture and private purposes. Generally, these vehicles are using propeller based propulsion systems. Thus, aerodynamic shape optimization is a vital process to improve their performance. Accordingly, in the present study, a Computational Fluid Dynamics (CFD) based open- source shape optimization framework (combined use of a CFD solver, Optimization solver, Free-Form Deformation (FFD) tool and Mesh Generator utility) is designed to optimize the shape of a generic UAV propeller. As a result, the open-source shape optimization framework here woks quite efficiently and the Figure of Merit (FM) of the propeller has been improved by around 40 %. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicle (UAV) selection is not an easy decision as many alternatives and criteria must be evaluated at the same time. This selection decision requires the consideration of many different criteria including payload capacity, maximum speed, endurance, altitude, avionics systems, price, economic life, and maximum range. The main aim of this study is to decide the most appropriate UAV by considering these criteria. The fuzzy logic-based fuzzy Choquet integral methodology is used to select this vehicle which allows decision-makers to define references as linguistic and in interval range. A numerical example is presented to analyze the applicability of the proposed approach. The proposed approach resulted in a successful application by comparing different UAVs and the most appropriate vehicle is selected at the final stage. [ABSTRACT FROM AUTHOR]

Quadrotors are well - known unmanned aerial vehicle structures that have some advantages such as hovering, vertical take - off and landing, and low - speed flight. On the other hand, quadrotors are subjected to modeling and sensor uncertainties that lead to erroneous state estimation. Kalman filter has been proven to be the optimal estimator for the Gaussian distributed noise for linear processes. However, linear dynamical models of the quadrotors are not accurate representations of the systems due to nonlinearities, and coupling between the states. Extended Kalman filter (EKF) is proposed to solve the above issue. But, first order Taylor series approximation for the nonlinear state model may lead inefficiencies. For this reason, another Kalman filter framework is proposed that employs unscented transformation (UT). Unscented Kalman filter (UKF), can model the state distribution as Gaussian random variable to the third degree for arbitrary nonlinearities. So, in this study, unscented Kalman filter based estimation scheme is presented to overcome the sensor and model noises for nonlinear quadrotor attitude dynamics. According to the statistical analysis, the approach can estimate and reduce the mean absolute error, root mean square error and also variance of the noise for all attitude states. This study was supported by Eskişehir Technical University Scientific Research Projects Commission under the grant no: 20ADP229. [ABSTRACT FROM AUTHOR]

In this paper, a two-dimensional-straight-line path following methodology for an unmanned aircraft is developed. With the developed algorithm, the unmanned aerial vehicle is made to converge to a predefined path, and then to follow a virtual target on the path. Unlike similar algorithms, the location of virtual target is defined as a function of the distance between the aircraft and path itself. By this way, according to the distance between the aircraft and path, the aircraft firstly heads directly to the path then follow it to the next point. The location of the virtual target is changed according to the magnitude of the cross track error which is the distance between the path and the aircraft itself. After defining the equations required for the calculation of the desired heading, the applied closed controller is explained. A numerical simulation model is created for the solution of equations of motion to investigate the outputs of the path following algorithm. The results of the algorithm and simulation are evaluated. [ABSTRACT FROM AUTHOR]

In this study sensor/actuator fault detection, isolation and accommodation is performed using innovation sequence analysis in a small Unmanned Aerial Vehicle (UAV) model. Sensor/actuator fault detection and isolation is an important part of a faidt tolerant control system. In the study ways of determining the faults that occur in sensors and actuators, distinguishing between them and isolating the faults in the sensors is described. Kalman filtering technique is used to build a faidt detection and isolation algorithm and a robust Kalman filter is designed to distinguish between actuator and sensor faults. A simplified robust adaptive Kalman filter is also built to estimate the states in case of measurement system malfunctions. The small UA V model is used for simulations and faults occurring in speed sensors and elevators are simulated. [ABSTRACT FROM AUTHOR]

In this paper, the robust control system is designed by using Model Predictive Control for ZANKA-I which is an unmanned aerial vehicle, and its performance is analyzed. In order to design the control system, longitudinal and lateral stability of the vehicle are modeled and converted to longitudinal and lateral state-space model, respectively. Also, the effects of turbulence on longitudinal and lateral stabilityare parametrically modeled and numerically inserted into the state-space models. As a result of simulating the model, the robustness of control system is proved. [ABSTRACT FROM AUTHOR]

In 1990s, a new software development approach named "agile", suggested new methodologies for projects of relatively short duration and changing requirements. Such software projects which start with uncertain requirements are considered risky under classical approaches, but they became fairly successful by using these newer methods. Agile methods favor working software to detailed documentation, they are open to change and they prefer strong interaction with customers. This study reports the results of a project development effort deriving its development process from different agile methods adapted for the circumstances. The project aims to develop a university automation system by a software team which was initially unfamiliar with the agile software development approach and internet based programming technologies. We describe how to tailor and implement the chosen practices from the different agile methods, which challenges were addressed during the implementation, and the ways to solve these challenges. Furthermore, we comment on the experience gained and make recommendations on the implementation of these practices. [ABSTRACT FROM AUTHOR]

In this study, it is aimed to analyze an unmanned air vehicle (UAV) design parameters, to finish design calculations and aerodynamic and performans calculations. Therefore, this study helps UAV works carried out within the Turkish Air Force Academy undergraduate and graduate training programs. Within the study, the goal is to design and build a propeller driven, electric powered, unmanned "Surveillance and Attack" R/C airplane which is capable of flying three predefined missions: Ferry Flight, Surveillance Flight and Stores Release/Asymmetric Loads Flight.So, in the design phase, so many package programs are used to obtain visual details. In manufacturing phase, TUAF (Turkish Air Force Academy), ITU (Istanbul Technical University) and Baykar Machinarys' all opportunities and capabilities were benefitted from. [ABSTRACT FROM AUTHOR]

In this study, it is studied that the augmented Wind-FLOWER numerical modelling skill's applications and land-surface (orographic) air flows' numerical modelling on mountain areas by using real topography datas which are defined on geographic areas. This numerical modelling skill's simulation results show that 3-D specifications are very important for being of time-dependant quick-change vortex which are included by landsurface air flows. In the numerical modelling skill's applications topographical numerical altitude datas that include informations and datas of really "Numerical Altitude Model (NAM)" are used. These real topographic datas, used in application part, are examinated very tightly and seperated same size topographic datas before using as initial/beginning datas for Wind-FLOWER numerical modelling. Then, these topographical datas are used as land-surface data for modelling applications. This modelling applications include a pro-precessor and a post-processor. The pro-precessor runs land-surface numerical datas and uses them in numerical modelling applications. The post-processor constitutes 2-D and 3-D images by using the numerical modelling applications' datas of land-surface air flow and determined vortex formations and vortex-density distrubitions. Furthermore, a "Graphical User Interface (GUI)" is constituted which is required to work with pre-processor and postprocessor and is practiced for easy usage of numerical modelling. [ABSTRACT FROM AUTHOR]