Browsing by Author "Malandrakis, Konstantinos"

Now showing 1 - 5 of 5
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    Design and development of a novel spherical UAV
    (Elsevier, 2016-10-03) Malandrakis, Konstantinos; Dixon, Roland; Savvaris, Al; Tsourdos, Antonios
    This paper presents the design and system integration of a novel coaxial, flap actuated, spherical UAV for operations in complex environments, such as buildings, caves or tunnels. The spherical design protects the inner components of the vehicle and allows the UAV to roll along the floor if the environment permits. Furthermore, the UAV can land and takeoff from any orientation and come into contact with objects without putting the propellers at risk. Flaps at the base of the sphere will generate roll and pitch moments as opposed to conventional swash plate designs while the coaxial setup will provide the necessary yaw moments and increase in thrust to volume ratio of the system. The flaps, placed below the propellers allow for decoupled roll and pitch control in a thrust vectoring manner. The final result of this design is a well-protected, compact, easily controlled, flexible and agile UAV for operations in complex environments. The spherical UAV was successfully flight tested on a number of occasions with various PD and µ-synthesis robust control systems and was observed to be easily stabilised and resistant to external disturbances to certain extent.
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    Development of a fuel cell hybrid-powered unmanned aerial vehicle
    (IEEE, 2016-08-08) Savvaris, Al; Xie, Ye; Malandrakis, Konstantinos; Tsourdos, Antonios
    This paper describes the design and development of a hybrid fuel cell/battery propulsion system for a long endurance small UAV. The high level system architecture is presented, followed by the hardware-in-the-loop testing and performance analysis. A high fidelity 6-DoF simulation model of the complete system was developed and used to test the system under different battery state-of-charge. The simulation model included the power manager for the hybrid propulsion system configuration, which is based on rule-based control. The simulation results are compared with the experimental results obtained from the Hardware-in-the-Loop testing.
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    Inspection of aircraft wing panels using unmanned aerial vehicles
    (MDPI, 2019-04-17) Tzitzilonis, Vasileios; Malandrakis, Konstantinos; Zanotti Fragonara, Luca; Gonzalez Domingo, Jose Angel; Avdelidis, Nicolas Peter; Tsourdos, Antonios; Forster, Kevin
    In large civil aircraft manufacturing, a time-consuming post-production process is the non-destructive inspection of wing panels. This work aims to address this challenge and improve the defects’ detection by performing automated aerial inspection using a small off-the-shelf multirotor. The UAV is equipped with a wide field-of-view camera and an ultraviolet torch for implementing non-invasive imaging inspection. In particular, the UAV is programmed to perform the complete mission and stream video, in real-time, to the ground control station where the defects’ detection algorithm is executed. The proposed platform was mathematically modelled in MATLAB/SIMULINK in order to assess the behaviour of the system using a path following method during the aircraft wing inspection. In addition, two defect detection algorithms were implemented and tested on a dataset containing images obtained during inspection at Airbus facilities. The results show that for the current dataset the proposed methods can identify all the images containing defects.
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    Inspection of aircraft wing panels using unmanned aerial vehicles
    (IEEE, 2018-09-03) Malandrakis, Konstantinos; Savvaris, Al; Gonzalez Domingo, Jose Angel; Avdelidis, Nicolas Peter; Tsilivis, Panagiotis; Plumacker, Florence; Zanotti Fragonara, Luca; Tsourdos, Antonios
    In large civil aircraft manufacturing a time-consuming post-production process is the non-destructive inspection of wing panels. This work aims to address this challenge and improve the defects' detection by performing automated aerial inspection using a small off-the-shelf multirotor. The UAV is equipped with a wide field-of-view camera and an ultraviolet torch for implementing non-invasive imaging inspection. In particular, the UAV is programmed to perform the complete mission and stream video, in real-time, to the ground control station where the defects' detection algorithm is executed. The proposed platform was mathematically modelled in MATLAB/SIMULINK in order to assess the behaviour of the system using a path following method during the aircraft wing inspection. The UAV was tested in the lab where a six-meter-long wing panel was one-side inspected. Initial results indicate that this inspection method could reduce significantly the inspection time, cost, and workload, whilst potentially increasing the probability of detection.
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    Rule-based conflict management for unmanned traffic management scenarios
    (IEEE, 2020-11-18) Alharbi, Abdulrahman; Poujade, Arturo; Malandrakis, Konstantinos; Petrunin, Ivan; Panagiotakopoulos, Dimitrios; Tsourdos, Antonios
    The growing use of Unmanned Aerial Vehicles (UAVs) operations will require effective conflict management to keep the shared airspace safe and avoid conflicts among airspace users. Conflicts pose high risk and hazard to human lives and assets as they ma may result in financial and human loss. The proposed rule-based conflict management model consists of three main stages. The first stage includes strategic deconfliction during the flight plan generation. The second stage, pre-tactical deconfliction, applies a ground delay to the agent to resolve the conflict. The third stage corresponds to the tactical deconfliction, where the drone hovers or loiter in the last waypoint before the conflict area until the conflict time window passes. The proposed method differs from most existing conflict management approaches in that it applies deconfliction methods sequentially using a rule-based strategy. Furthermore, a high number of published studies do not consider realistic airspace constraints and potential airspace modernization concepts such as dynamic flight restrictions Assessment and validation are performed in three simulation scenarios that consider different patterns of the airspace availability in the areas where flights may be restricted, such as airfields, recreational areas, and prisons. The Particle Swarm Optimization (PSO) algorithm was used for drone path planning. For the simulated scenarios all of the conflicts were resolved after implementation of the proposed method. The implemented method is simple, flexible and suitable for the management of more complex and dense airspaces.