bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards numerical simulation of fatigue damage detection in CFRP laminates by modelling of stochastic vibration response
Authors: Tsivouraki Niki , Tserpes Konstantinos , Fassois Spilios
Published: June 2023

Due to the widespread use of composites in aerospace applications, there is an increasing need for developing Structural Health Monitoring (SHM) systems for composite structures. In this process, simulation models can play a crucial role by contributing to the optimization of the experimental techniques and to understanding of the physical mechanisms. The objective of this work is to numerically simulate fatigue damage detection in laminated composites subjected to random vibration through a white gaussian noise. To this end, the ANSYS FE code has been used. The developed FE model represents an experimental set-up consisting of the composite specimen, the speakers producing the white noise and the measuring equipment. 24 specimens were modelled in total, a healthy one and 23 damaged ones. The white noise was modelled by introducing a normalized sequence of numbers adapted to the free vibration eigenfrequency range. Fatigue damage in the form of matrix cracking and delamination was modelled based on C-Scan images of fatigued specimens by degrading the appropriate elastic properties of the layers in specific groups of elements. Damage of different geometry, size, and type was modelled. The numerical results are in the form Power Spectral Density (PSD) diagrams, natural frequencies, eigenfrequencies and contour plots. The comparison between the numerical and experimental eigenfrequency values show a maximum deviation of 1.7%. The numerical results show a change in the vibration response even in the presence of a small damage, which is an indication of the sensitivity of the method. A significant decrease in natural frequencies of the specimen with the damage accumulation is observed. The present model comprises the first effort towards a fully validated digital twin which will be used for the virtual testing and the optimization of the vibration test.
CubeSat satellite patch antenna designed with 3D printable materials: a numerical analysis
Authors: Pittella Erika , D’Alvia Livio , Piuzzi Emanuele
Published: June 2023

The paper presents a compact patch antenna system designed using 3D printable materials and compatible with any CubeSat satellite structure. Small satellites are transforming the space industry, allowing space access with an important cost reduction for satellite industries and a shorter plan development time compared to bulky satellites. Moreover, using additive manufacturing, it is possible to design specific system components, also with a complex geometry of the inner part, without material wasting. Furthermore, a key point of 3D printing is to allow to go from design to construction straight, having an enormous effect on the supply chain. Generally, CubeSats count on Very High Frequency and Ultra High Frequency communication systems for low bit-rate uplink and downlink. Instead, S-band is among the favourite choices for high bit rates since the frequency range 2.40–2.45 GHz is one of the International Telecommunication Union (ITU) amateur satellite frequency range. An S-band printed antenna system is designed in the present paper, considering the limitations on size and the weight of CubeSat standard. The antenna system is simulated with an electromagnetic CAD, using the polylactic acid as substrate, or polylactide, a thermoplastic polyester widely used in 3D printing.
Development of an urban air mobility vehicle family concept by system of systems aircraft design and assessment
Authors: Ratei Patrick , Naeem Nabih , Prakasha Prajwal Shiva
Published: June 2023

The concept of urban air mobility promises a modern air taxi transport solution providing on-demand air mobility and hence time savings compared to congested terrestrial transportation in major cities and metropolitan areas. To make it a reality, vehicles, infrastructure, services, and operations must be developed simultaneously and cross-linked. These interconnections and interactions of the multitude of systems involved necessitate a system of systems approach, which is accounted for and implemented through agent-based simulations. Accordingly, the system of systems simulation framework is tuned to vehicle architecture as well as fleet design and assessment, thus allows to expand the aircraft design process by fleet operations and transport network perspectives. In this paper, the top level aircraft requirements of electric vertical take-off and landing vehicles are investigated by a fleet-centric approach. Herein, two disparate configurations, i.e. multirotor and tiltrotor, are modelled to depict representative wingless and winged configurations. The optimal design points are found and traded off by formulating different measures of effectiveness accounting for conversion of passenger requests, fleet energy consumption, and vehicle load factor. In summary, this study demonstrates the need for system of systems simulations to derive market-and operations-tailored vehicles and fleets. Furthermore, work on heterogeneous fleet compositions is required.
Unleashing the potentials of digital twinning in the production of composite aircraft components
Authors: Baalbergen E H , de Marchi J A , Klerx R
Published: June 2023

The aircraft industry is continuously challenged to deliver more complex products in order to meet increasingly stricter regulations and growing customer demands, to provide better quality products in larger quantities, and to pay more attention to reusability and circularity issues. At the same time, the industry needs to work with lower costs, shorter lead and production times, less waste, delay, energy consumption, and emissions, and reduce its dependence on non-renewable materials. To keep up with these challenges, the industry automates and continuously innovates as much as is possible. The increasing use of composites in aircraft and aircraft components adds the extra challenge of rapidly bringing innovative manufacturing processes to the factory floor. Aircraft product design, analysis, testing, and production are increasingly being digitized and automated, and consequently involve, and produce, more and more data. Digital twinning is an important enabler for mastering and exploiting this ever-growing plethora of data. In this paper we discuss the potentials of digital twinning in innovative production processes in the aircraft industry, and describe first-hand results and experiences in developing and using digital twinning in the production of composite aircraft components, illustrated by concrete example applications.
Towards a human-centric Digital Twin architecture for Industry 5.0: Aiding skilled operators with composites production automation
Authors: de Marchi J A , Baalbergen E H
Published: June 2023

Industry 4.0 uses digitalization technologies to collect huge amounts of data during production processes. Digital twins can support processing, mastering, and exploiting the plethora of data to assist in optimizing production throughput [1]. But how can digital twins actually support skilled operators on the factory floor? In this paper, we present the design of an operator-centric digital twin for an automated composites production process from start to end, thereby exploring key elements of the architecture of the operator-tailored digital twin and exposing valuable lessons learned from the operator-centric design process. The development methodology applied, and the resultant digital twin architecture, show how operator-centric design guidelines are successfully translated into implementation. This approach helped transforming an otherwise straightforward Industry 4.0 implementation into a state-of-the-art Industry 5.0 implementation, wherein the digital twin plays a central role in supporting and assisting operator-based decision-making at the core of the production process [2].
Simplification of requalification procedure of outdated carbon/epoxy prepregs and scenarios of reuse
Authors: Amare Constance , Mantaux Olivier , Gillet Arnaud , Pedros Mathieu
Published: June 2023

As a result of their combined high mechanical performances and easy processability, carbon/epoxy prepregs are widely used in the manufacture of aerostructures. The resin of these materials is in an intermediate state of polymerisation which makes these materials perishable. Drastic manufacture conditions lead continuously to the generation of expired prepregs that, today, can no more be used in the aeronautic industry nor in other industries. Although requalification procedure can be carried out, its high cost does not always justify such a procedure. This is why large quantities of expired prepregs are send to landfill. The objective of the Cleansky project MANIFICA is to set up a complete recycling chain of carbon fibre composites “from aeronautic waste to innovative composite parts”. The aim of this work is to propose a simplified requalification procedure by avoiding unnecessary tests. These studies are illustrated by property measures on compliant and expired prepregs. The main results were that in most cases, aging induces processing difficulties while mechanical performance remains unaffected. It was also shown that a simpler requalification procedure was possible and that expired prepregs can be reused without loss of performance outside the aeronautical field. Rather than considering expired material as waste, MANIFICA offers several new reuse scenarios.
Manufacturing and LCA Data Collection for a Biomaterial a/c Interior Demonstrator using the example of a Drawer Box
Authors: Baucke Jan
Published: June 2023

In the environment of the CleanSky2 project ecoTECH, INVENT developed an alternative sustainable aircraft interior item.

The main objective of the ecoTECH project is to explore new solutions to reduce the environmental footprint of aircraft components during their global lifecycles and make these solutions available to the aviation industry.

In the Workpackage Biomaterial a/c Interior Demonstrator INVENT leads the development of a drawer box as an exemplary aircraft interior part, made from eco-friendly materials.

The benchmark with regard to economic and ecologic aspects is set by a state-of-the-art aircraft interieur item for which the new biomaterial drawer box is developed as a 100% substitute.

Along the way to catch up with this commercial example, several challenges that are typical for the use of biomaterials were faced during the different development phases which could be divided into material evaluation and selection, design, testing on specimen level and manufacturing of the demonstrator.

Especially the development of the material-appropriated design and manufacturing approach to compensate specific disadvantages of the selected eco-friendly materials to fulfill the same requirements as the state-of-the-art example, were central aspects and took up a large proportion of the overall effort. In parallel with the technical development, also a complete LCA data collection was prepared and later completed during the manufacturing phase of the biomaterials drawer box.

In combination with the EoL approaches, evaluated by the associated project ELIOT, the collected information forms a holistic picture of the environmental footprint over the lifecycle of the new interieur part.

This data set allows also a comparison with the already existing state-of-the-art drawer box not only under the aspects of weight and stability, but also regarding for example energy consumption, production time and recycling potential.

This project has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme
SBAS-based navigation system for precision approach in CAT II LVC
Authors: Kovar Martin , Cypriano Lucas Almeida , Kucera Matej , Ptacek Pavel
Published: June 2023

Due to lack of advanced navigation systems, secondary airports are normally unable to support instrument approaches in low visibility conditions (LVC) more adverse than Category (CAT) I, making them inaccessible during such conditions. Incoming flights are then delayed, diverted to adjacent airports, or cancelled before take-off. This paper presents an onboard navigation solution, under development in scope of SESAR 2020 Solution PJ02-W2- 17.2, which focuses on technology development to mitigate these traffic disruptions by enabling instrument approaches in CAT II LVC with minimum airport and air navigation service provider investments. The concept builds upon global navigation satellite systems (Global Positioning System L1 frequency – GPS L1, satellite-based augmentation system), which currently enables Localizer Performance with Vertical guidance (LPV) operation down to LPV 200 minima. The designed system includes radio altimeter-based aiding and innovative integrity algorithm to improve navigation performance in support of operations below 200ft down to CAT II / LPV 100 minima. As no such requirements have yet been officially published, authors also defined sets of candidates based on Instrument Landing System Collision Risk Model and other sources. The team developed and verified a Monte-Carlo fast-time simulation toolset to enable representative and statistically significant evaluation of the concept feasibility via its availability throughout Europe, as well as sensitivity to proposed sets of alert limits. Also, flight data collection and a developed software prototype allow for further validations. Simulations demonstrated over 95% average availability with the best results achieving level of 99% depending on used set of requirements. The solution enabling operations in LVC allows unlocking various benefits to business/airline operators (e.g., avoided extra costs, increased predictability), passengers (avoided opportunity loss) and airports (retained profit from flights, less traffic at diversion airports). Technology development also marks an important step towards gate-to-gate autonomous operations.
Modelling of a battery supported fuel cell electric power train topology for a regional aircraft
Authors: Staggat Martin , Ludowicy Jonas , Bahrs Victor , Link Antje , Kazula Stefan
Published: June 2023

Electrification of aircraft propulsion may offer a way towards carbon dioxide (CO2) neutral air travel. Here, the electric aircraft demonstrators already flying mostly rely on the use of batteries as energy source. While battery electric concepts may be suitable solutions for short range applications, such as urban air vehicles, the energy density of state of the art batteries is not yet sufficient to power regional aircraft with a typical range of 1000 nautical miles and 70 passengers. One possible topology option of a propulsion concept suitable for a regional aircraft is a hybrid composed of a fuel cell system (FCS) and a battery. On the one hand, this concept uses hydrogen (H2) as the primary energy carrier, resulting in a significant reduction of the required battery stack mass in comparison to a battery only aircraft. On the other hand, a battery support of flight phases with high power demand, such as take-off or climb, allows a smaller dimensioning of the fuel cell system and the corresponding thermal management system (TMS) and therefore additional overall system mass benefits in comparison to a fuel cell only aircraft. The present paper analyses the weight reduction potential of a battery stack supported fuel cell system electric power train architecture for a typical regional aircraft with regard to the hybridization factor (HF) and battery specific energy (BSE). The modelling includes the sizing of the fuel cell system and the battery stack, other mechanical and electric components, such as gearboxes, electric motors and power electronics and the corresponding TMS. The according electrified aircraft is resized, keeping wing loading and power-to-weight ratio constant. The best combination of HF and BSE yielding the lowest MTOM with 27 100 kg is still about 19.9 % heavier than the conventionally powered reference aircraft with 22 800 kg. The study shows that future aircraft of similar weight and hence size require very advanced battery technology with regard to the BSE compared to available state of the art solutions.
Concepts for integrating electrical energy storage into CFRP laminate structures for aeronautic applications
Authors: Laurin Frédéric , Beutl Alexander , Jiang Qixiang , Kühnelt Helmut
Published: June 2023

The CleanSky2 THT project SOLIFLY is developing further structural batteries for aeronautical applications. This paper presents the concepts of structural integration and the methodology to evaluate the impact of structural battery integration on the mechanical properties of CFRP solid laminates considering the size and shape of the structural battery insert as well as its location through the laminate thickness. A fully parameterised, computationally efficient numerical strategy for finite element simulation has been implemented to evaluate the mechanical properties and, for the first time, the onset of matrix damage as the cell geometry and integration location are varied. The first mechanical characterisation data of SB cell components and cell prototypes were obtained thanks to multi-instrumented tensile tests using digital image correlation and acoustic emission. An initial assessment of the advantages and trade-offs of the SB integration concepts with respect to functionally separated components is discussed.
Functional and Safety Challenges of Hydrogen Fuel Cell Systems for Application in Electrified Regional Aircraft
Authors: Kazula Stefan , Staggat Martin , Graaf Stefanie de
Published: June 2023

This paper identifies potential weaknesses and challenges of hydrogen fuel cell systems as main energy provider for electrified aircraft propulsion and presents potential solutions. The general design, operating principles and main characteristics of hydrogen-fuelled low-temperature polymer electrolyte membrane fuel cell systems (PEMFCSs) are described. The safety assessment process in aviation according to Aerospace Recommended Practices ARP4754A and selected methods according to ARP4761 are introduced. The functions of fuel cell systems in electrified aircraft powertrains are analysed in functional structure trees on aircraft, powertrain and fuel cell system level. By means of a Functional Hazard Analysis (FHA), potential malfunctions and their effects are investigated and their severity is evaluated. Critical failure modes are identified and requirements for acceptable failure probabilities are stipulated. Solution options to mitigate failure effects are stated. The results of the mentioned analyses reveal design challenges associated with the application of fuel cell systems in electrified aircraft propulsion, for instance, concerning functional independence as well as solutions for cold start conditions, heat transfer and lightweight design. Furthermore, safety challenges arise due to the utilisation of cryogenic hydrogen as fuel and the high amount of electric energy.
Fault-tolerant switched reluctance motor propulsion system for eVTOLs
Authors: Biczyski M , Sehab R , Whidborne J F , Krebs G , Luk P C K
Published: June 2023

eVTOLs are receiving a lot of attention as a potential solution to urban air mobility challenges. Many configurations are multirotors, which are open loop unstable, therefore very susceptible to actuator failures. Due to their usually short mission duration (20-30 min), fault-tolerance of the propulsion system is of greater importance then reliability. Thus, novel approaches to enhance this capability are required. This study proposes a new fault-tolerant propulsion system using 4-phase switched reluctance motors. It is designed for an 8-10 kg scale multirotor eVTOL, to replace redundant coaxial brushless DC motors with a single fault-tolerant drive. Acknowledging the role of fault-tolerant control algorithms, the propulsion system is validated in terms of the loss of effectiveness metric, typically used in the evaluation of control solutions. The switched reluctance motor propulsion system was found to be highly resilient to open phase and current sensor faults, but susceptible to position sensor faults. This can, however, be mitigated with sensorless control solution. Extending the findings to full-scale eVTOLs is also discussed.
In-situ identification of ice accumulation profile and vibration response at composite blades under various icing conditions
Authors: Filippatos Angelos , Schwab Simon , Tzortzinis Georgios , Madia Evgenia , Gude habil. Maik
Published: June 2023

Icing challenges the safety and performance of wind turbines in low temperature environments. Detailed information on the amount and location of ice on rotor blades can facilitate decision making and mitigate hazardous effects. Therefore, a better understanding of the relation between ice accumulation and frequency response is required. Small scale experiments are conducted employing rotor blade specimens, experiencing natural icing of different configuration in terms of temperature and ice extent. The ice distribution is measured with a high-resolution laser scanner, and an algorithm based on alpha shapes is developed to determine the growth of the ice volume. Experimental modal analyses are performed periodically during the icing process, detecting consequent effects in the corresponding frequency spectra. The collected data is assessed regarding its suitability for an ice detection system and serves as a starting point for further developments.
Health monitoring of the shaft bearings in a micro turbojet based on vibration analysis
Authors: Przysowa Radoslaw , Majewski Paweł , Ślęczek Jakub , Grundas Dariusz , Wachłaczenko Michał
Published: June 2023

In a recently implemented aerial target, the propulsion system consists of two JetCat micro turbojet engines. Due to the limited durability of the rotor support bearings, the engine operation time has been limited to two hours or two flights. In addition, after each flight, an engine bench test with vibration measurement is required. The adopted maintenance system is also labor-intensive and costly due to obligatory shaft bearing inspections performed frequently in the repair shop. These problems result from the limitations of the available high-speed bearing technology and the high rotor loads related to aircraft maneuvers in the air. The goal of the work is to develop a method for assessing the health of the main shaft bearings in the micro turbojet based on vibration signals. Methods known from full-scale jet engines were adapted for monitoring the health of the main shaft bearings. An accelerometer and rotational speed sensor were mounted on the engine. Vibration and other parameters of the engine were measured and analyzed, and then symptoms of damage were sought. The vibrations of seven JetCat engines were analyzed, selecting the one for further destructive testing. In all three axes X, Y and Z, the vibration components related to the rotational frequency and its orders are dominant, especially EO2 and EO3 related to rotor dynamics. Continuous engine vibration monitoring is a promising way of extending engine life and avoiding the deficiencies of microturbines related to their size and low-cost technology. The obtained results indicate that the tested JetCat engines have a life reserve, which has so far been used to a small extent.
Prognostics of aerospace electromechanical actuators: comparison between model-based metaheuristic methods
Authors: Baldo L , Dalla Vedova M D L , Querques I , Maggiore P
Published: June 2023

Electro-Mechanical Actuators (EMAs) deployment as aircraft flight control actuators is an imperative step towards more electric concepts, which propose an increased electrification in aircraft subsystems at the expense of the hydraulic system. Despite the strong benefits linked to EMAs adoption, their deployment is slowed down due to the lack of statistical data and analyses concerning their often-critical failure modes. Prognostics and Health Management (PHM) techniques can support their adoption in safety critical domains. A very promising approach involves the development of model-driven prognostics methodologies based on metaheuristic bio-inspired algorithms. Evolutionary (Differential Evolution (DE)) and swarm intelligence (particle swarm (PSO), grey wolf (GWO)) methods are approached for PMSM based EMAs. Furthermore, two models were developed: a reference, high fidelity model and a monitoring, low fidelity counterpart. Several failure modes have implemented: dry friction, backlash, short circuit, eccentricity and proportional gain. The results show that these algorithms could be employed in pre-flight checks or during the flight at specific time intervals. Therefore, EMA actual state can be assessed and PHM strategies can provide technicians with the right information to monitor the system and to plan and act accordingly (e.g. estimating components Remaining Useful Life (RUL)), thus enhancing the system availability, reliability and safety.
Bird strike simulation on a bonded Ti/CFRP leading edge of an engine fan blade
Authors: Papadopoulos Kosmas , Floros Ioannis , Tserpes Konstantinos
Published: June 2023

Bird strike represents a critical loading scenario for aeronautical structures, especially for engine fan blades. It is, therefore, of great importance both to protect the leading edge of the fan blade from impact damage and to be able to detect impact damage directly. In the present study, an explicit finite element (FE) model was developed using the LS-DYNA software to simulate bird strike on the leading edge of a CFRP fan blade protected by an adhesively bonded Ti layer. The model accounts for damage on the CFRP blade through a progressive damage modeling scheme and for debonding through a cohesive zone modeling scheme but not for damage on the Ti layer. For the modeling of the bird, the smooth particle hydrodynamics (SPH) method was used, due to the large deformations that were expected. Using the model, a parametric study on the effects of bird mass and impact energy was performed. The numerical results show that impact damage depends more on impact velocity than the bird mass. In all cases, debonding of the tip of the leading edge was predicted, while for combinations of small bird mass and large impact velocity a more extensive debonding of the protective layer was predicted. Regarding damage in the CFRP, only matrix cracking on the leading edge has been predicted. Aiming to assess the effectiveness of FBGs to detect debonding of the Ti layer due to bird strike, an FBG network has been modeled into the bondline and a study was performed on the correlation of the measured strains with impact damage.
Lumped parameters multi-fidelity digital twins for prognostics of electromechanical actuators
Authors: Quattrocchi Gaetano , Dalla Vedova Matteo D.L. , Berri Pier Carlo
Published: June 2023

The growing affirmation of on-board systems based on all-electric secondary power sources is causing a progressive diffusion of electromechanical actuators (EMA) in aerospace applications. As a result, novel prognostic and diagnostic approaches are becoming a critical tool for detecting fault propagation early, preventing EMA performance deterioration, and ensuring acceptable levels of safety and reliability of the system. These approaches often require the development of various types of multiple numerical models capable of simulating the performance of the EMA with different levels of fidelity. In previous publications, the authors already proposed a high-fidelity multi-domain numerical model (HF), capable of accounting for a wide range of physical phenomena and progressive failures in the EMA, and a low-fidelity digital twin (LF). The LF is directly derived from the HF one by reducing the system degrees of freedom, simplifying the EMA control logic, eliminating the static inverter model and the three-phase commutation logic. In this work, the authors propose a new EMA digital twin, called Enhanced Low Fidelity (ELF), that, while still belonging to the simplified types, has particular characteristics that place it at an intermediate level of detail and accuracy between the HF and LF models. While maintaining a low computational cost, the ELF model keeps the original architecture of the three-phase motor and the multidomain approach typical of HF. The comparison of the preliminary results shows a satisfactory consistency between the experimental equipment and the numerical models.
Evolution of the Tactical Separation System to support the Integrated Mission Management System in the COAST project
Authors: Vito V Di , Torrano G , Cerasuolo G , Ferrucci M
Published: June 2023

This paper refers to the developments of the single pilot enabling technologies that are designed, implemented and validated in the Clean Sky funded project COAST (Cost Optimized Avionics SysTem). The target industry domain of such technologies is the aviation segment of Small Air Transport (SAT), referring specifically to commuter category vehicles (5 to 19 pax), under the EASA CS-23 regulation. Among the several technologies that have been designed, developed and demonstrated in flight, there is the Tactical Separation System (TSS), which reached TRL 6 in 2021 thanks to successful flight demonstration. It represents fundamental decision-making support system, able to assist the single pilot in the management of the separation task, under delegation of the separation responsibility to the pilot by the ATC. Nevertheless, in order to properly integrate and enhance the individual enabling technologies for single pilot operations, in the COAST project a unique Integrated Mission Management System (IMMS) is being designed. It constitutes a further technological advancement to support more effective and safe management of situations of pilot’s incapacitation during the flight, under single pilot operations, and a relevant step forward towards more autonomous aircraft. To support the IMMS implementation, therefore, the Tactical Separation System is currently subject to proper evolution, in order to include specific functionalities that will be needed as part of the IMMS. This paper outlines the main outcomes from the design and demonstration of the Tactical Separation System as individual technology. After that, it describes the IMMS and the specific role that the tactical separation functionality will play in such framework. Finally, the paper reports the evolved TSS version design currently ongoing in the COAST project, with specific focus on the implementation of the tactical traffic clustering functionality.
Tackling different aspects of drone services utilizing technologies from cross-sectional industries
Authors: Purucker P , Reis R JN , Larsen M , Ryabokon A , Giovagnola J , Filho E , Reil C , Höß A , Barreto Guerra JP , Molina M , Duarte Penna S , Politi E
Published: June 2023

Enabling autonomous and Beyond Visual Line of Sight (BVLOS) operation of Unmanned Aerial Vehicles (UAVs) in the Very Low Level (VLL) airspace requires further advancement of technologies such as sensing the environment or secure and reliable communication. This paper addresses these challenges by presenting solutions developed within the project Airborne Data Collection on Resilient System Architectures (ADACORSA). Here, findings from cross-sectional areas such as the automotive industry are being further enhanced to fulfill the demands of aviation, in particular for use in the UAV domain. The developed technologies include an advanced Ethernet-based deterministic network for reliable onboard communication, a multi-sensor architecture for sensing the spatial environment as well as a multi-link communication gateway that provides reliable communication to the ground and a secure handover architecture.
Design and SITL Performance of an online Distributed Target Estimation for UAV Swarm
Authors: Lizzio Fausto Francesco , Primatesta Stefano , Guo Haoyu , Guglieri Giorgio
Published: June 2023

In this paper, an online distributed target estimation for a swarm of Unmanned Aerial Vehicles in formation flight is considered. In particular, a flocking algorithm is employed to handle the formation task, while a Distributed Kalman Filter in the Information form is used to perform the estimate of a mobile target state. Software-In-The-Loop simulations are carried on in the ROS/Gazebo environment to illustrate the coupling between the formation and the estimation tasks. Moreover, the influence of swarm connectivity in the estimation process is analyzed, showing the benefits of information fusion.
Analysis of the impact of GNSS disruptions on aircraft operations at Romanian airports
Authors: Ivan Antonia Nicoleta , Pandele Constantin Alexandru , Ionescu Bianca , Grigorie Teodor Lucian
Published: June 2023

In the transition towards space-based air navigation, the reliance on Global Navigation Satellite Systems (GNSS) is increasing. However, GNSS disruptions and interference can cause GPS loss in the cockpit. The purpose of this paper is to assess the impact of GNSS vulnerabilities, especially interference, on aircraft operations. The data used for this analysis was collected by GNSS monitoring stations installed at two Romanian airports, specifically selected due to their proximity to possible interference sources. In order to obtain relevant results, the entire assessment is based on the scenario in which all the flights at the airport are using GNSS as their primary means of navigation. Therefore, the flights that could have possibly been affected were identified and the operational impact of interference was assessed. This study emphasises the importance of GNSS monitoring at airports in order to reduce the negative effects of GNSS disruptions on the safe and efficient operations of aircraft.
Integrating ATM and air transport into multimodal transport system for Door-to-Door travel: the X-TEAM D2D project proposed approach
Authors: Vito V Di , Dziugiel B , Meincke P A , Mota M Mujica , Bagamanova M , Duca G , Russo R , Montaquila R V , Cerasuolo G , Maczka M , Mazur A , Naser F , el Makhloufi A , Proietti S
Published: June 2023

The project X-TEAM D2D (Extended ATM for Door-to-Door Travel) has been funded by SESAR JU in 2020 and completed its activities in 2022, pursuing and accomplishing the definition, development and initial assessment of a Concept of Operations (ConOps) for the seamless integration of ATM and air transport into an overall intermodal network, including other available transportation means (surface, water), to support the door-to-door connectivity, in up to 4 hours, between any location in Europe. The project addressed the ATM and air transport, including Urban Air Mobility (UAM), integration in the overall transport network serving urban and extended urban (up to regional level) mobility, specifically identifying and considering the transportation and passengers service scenarios expected for the near, medium and long-term future, i.e. for the project baseline (2025), intermediate (2035) and final (2050) time horizons. In this paper, the main outcomes from the project activities are summarized, with particular emphasis on the studies about the definition of future scenarios and use cases for the integration of the vertical transport with the surface transport towards integrated intermodal transport system and about identification of the barriers towards this goal. In addition, an outline is provided on the specific ConOps for the integration of ATM in intermodal transport infrastructure (i.e. the part of the overall ConOps devoted to integration of different transportation means) and on the specific ConOps for the integration of ATM in intermodal service to passengers (i.e. the specific component of the ConOps devoted to design of a unique service to passengers). Finally, the main outcomes are summarized from the validation of the proposed ConOps through dedicated simulations.
Operational Concepts for Urban Air Mobility deployment in the next decades
Authors: Di Vito V , Dziugiel B , Melo S , ten Thije J , Duca G , Liberacki A , Hesselink H , Giannuzzi M , Menichino A , Witkowska-Koniecz A
Published: June 2023

Urban Air Mobility development and deployment into future cities is gaining increasing and relevant interest in the last years, as a new mobility form suitable to meet the future greener, scalable and efficient mobility targets needed to solve the issues today’s big cities are facing in terms of traffic congestion as well as related environmental consequences. In this framework, the ASSURED UAM (Acceptance, Safety and Sustainability Recommendations for Efficient Deployment of UAM) project has been funded by H2020 and is ongoing, with the main objective of providing cities with knowledge concerning deployment of UAM services and definition of necessary standards and recommendations assuring common acceptance, safety and sustainability within integrated metropolitan transport system for three time horizons (2025, 2030 and 2035). In the project, dedicated activities have been carried out to develop operational concepts for Urban Air Mobility (UAM) deployment in the next decades. The main results from these activities are presented in this paper, which namely includes the main project outcomes in terms of: the identification of the most relevant and promising technologies that can enable the UAM implementation over the next decades, taking into account the current technological trends and perspectives; the outline of the regulatory framework in which the UAM will be shaped in the next decades; the definition of the most relevant aspects and constraints affecting the UAM deployment from the point of view of integration of such new mobility form in the cities infrastructures; the outline of the foreseen UAM concept of operations and definition of the most relevant use case that are expected to be implemented in the cities over the three time horizons considered in the project, i.e. 2025, 2030 and 2035.
Artificial Situational Awareness Assessment of a Novel ATC Support System
Authors: Tukarić I , Samardžić K , Radišić T , Vetter C
Published: June 2023

This paper presents the application of an existing situational awareness framework to a newly developed artificial intelligence system to determine its awareness level. The system incorporates diverse automation techniques - knowledge graph, expert rules, machine learning - for gaining situational awareness and applying it in the field of air traffic control. Since the system was developed to serve as a foundation for exploring automation and artificial situational awareness, the primary result of this work is the system’s overall awareness level assessment and the identification of sub-systems that may be improved for additional awareness. The framework used was chosen in the fundamental project documents and its use proved beneficial as it enabled the demonstration of how general guidelines can be interpreted for a specific system. It also informed possible routes for improvement of the process. Highest priority awareness-related improvements are those dealing with robustness, whose implementation would substantiate the current awareness assessment. The system is shown to be on the highest awareness level conditionally, considering its proof-of-concept level. The high level reached by the system is contingent on awareness concept and condition interpretations. With the appropriate assessment of the system, implementation in an operational environment is more feasible.
Most influential factors in the detection of potential conflicts between en-route aircraft by ATCO
Authors: Jurado Raquel Delgado-Aguilera , Comendador Víctor Fernando Gómez , Suárez María Zamarreño , Moreno Francisco Pérez , Gallego Christian Eduardo Verdonk , Valdés Rosa María Arnaldo
Published: June 2023

The objective of this methodology is to create a model capable of analysing and predicting the identification of potential conflicts between aircraft during en-route flights by air traffic control operators (ATCOs). This aspect is crucial to prevent Separation Minima Infractions (SMIs) and ensure safety. Initially, a Bayesian Network Model (BNM) is developed to define the safety event and its key dimensions. Using descriptive analysis and statistical knowledge, appropriate models are selected to represent the frequency of safety events. In addition, a data-driven approach is used to enhance model development. The BNM is calibrated, adjusted and subjected to sensitivity analysis using real data. The explanatory power and mixed effects of models and independent variables are assessed. By considering mixed effects in the sensitivity analysis, safety performance is characterised not only in terms of individual dimensions, but also in terms of their combinations. This allows the identification of threshold values that would minimise the occurrence of safety incidents.
Is it possible to evaluate the event-based taskload of an air traffic controller using an air traffic control simulator?
Authors: Suárez María Zamarreño , Valdés Rosa María Arnaldo , Moreno Francisco Pérez , Jurado Raquel Delgado-Aguilera , Frutos Patricia María López de , Comendador Víctor Fernando Gómez
Published: June 2023

Air Traffic Controllers (ATCOs) perform safety-critical tasks and face a wide variety of demands to manage aircraft safely and efficiently. In order for these demands to not result in a degradation of their performance, they need to be within certain upper and lower limits. In the field of human factors in aviation, one option to establish these limits is to study neurophysiological variables related to human performance. The problem is that the study of these variables can only be done on the basis of an adequate taskload baseline, which allows to accurately define the situation of the scenario during the course of the experiment. Taskload is a measure that quantifies the difficulty a person encounters in completing a task. CRITERIA project (atC event-dRiven capacITy modEls foR aIr nAvigation) aims to establish capacity models and study neurophysiological variables against taskload distribution profiles based on ATC events that appear in real-time simulations. This study presents the methodology defined in CRITERIA to evaluate the taskload of ATCOs based on ATC events, as well as the analysis of the first results obtained from a set of real-time simulations of four exercises with six participants using SkySim simulator.
Probabilistic and Statistical Analysis of Aviation Accidents
Authors: Amaral Yanne , Santos Luís F. F. M. , Valério Duarte , Melicio Rui , Barqueira Ana
Published: June 2023

The aim of this paper is to study the role that probabilistic and statistical analysis tools, such as ARIMA models, can have in the improvement of aviation safety levels. This is to be achieved by using available accident data, organizing it probabilistically, based on the different variables involved giving a better understanding of them as well as trough time series analyses forecast future values and trends. The results achieved provide valuable information usable by different aviation entities to be used on the accident prevention field through a proactive approach with regards to identified key areas.
Machine learning in aviation: Is it possible to predict when an ATC Sector or Air Traffic Flow will be regulated?
Authors: Moreno Francisco Pérez , Comendador Víctor Fernando Gómez , Jurado Raquel Delgado-Aguilera , Suárez María Zamarreño , Janisch Dominik , Valdés Rosa María Arnaldo
Published: June 2023

Due to the increasing complexity of airspace, the ATC system does not have sufficient capacity to cope with aircraft demand. For this reason, the ATFCM system needs to implement more and more measures to balance capacity and demand. These measures are the ATFCM regulations. In this paper, a methodology to predict ATFCM capacity regulations based on a machine learning model is proposed. This model will try to predict whether an ATC sector will be regulated or not at a specific time based on the time of prediction and certain operating variables in the sector. A test has been carried out in the LECMPAU sector of Spanish airspace. With results of 91% accuracy in predicting whether the sector will be regulated or not and a logical explainability, it can be concluded that with the sufficient historical operation and certain operational variables, it is possible to predict when an ATFCM regulation capacity will appear in the airspace. It can also be concluded that without a detailed knowledge of the operation in a sector, it is possible to make this prediction because patterns can be found in historical behaviour.
Ammonia fuelled space electric propulsion systems using C12A7:e- electride as electron emitter
Authors: Plaza J. F. , Toledo J. , Post A.
Published: June 2023

Given the significant changes taking place in the geopolitical global situation, and the derived supply chain issues for some traditional electric propulsion propellants like xenon, alternative propellants issue is perceived as a strategic topic to tackle, and ammonia (NH3) is becoming one serious candidate. Ammonia is increasingly being investigated to extend green hydrogen use by overcoming the storage and transportation issues of hydrogen. Ammonia characteristics like its superior energy density and low temperature and/or pressure needs for storage (10 bar at 20°C for liquid ammonia), make it very valuable for simplified unexpensive energy storage and transportation, and these characteristics makes it also especially suitable for on-board spacecrafts electric propulsion purposes. Based on our research activities on ammonia generation and dissociation processes with C12A7:e- electride as catalyst, this work will describe the most relevant characteristics and properties associated to the advantages of using the cheap and abundant ammonia, and will also present and discuss the results of the first successful tests performed with ammonia as fuel for a C12A7:e- electride based neutralizer, including relevant endurance tests in operation conditions. Additionally, the dual application as propellant and on-board energy generation system of ammonia will also be discussed.
International planetary sunshade concept with a function-integrated and scalable support structure based on coreless filament winding
Authors: Maheswaran Tharshan , Mindermann Pascal , Acker Denis , Gresser Götz T. , Fasoulas Stefanos
Published: June 2023

Despite all current efforts, climate change is the greatest challenge of the 21st century. Since existing measures will fail to prevent critical tipping points from being reached, in addition to terrestrial geoengineering methods, efforts are underway to explore new ways to implement space-based geoengineering methods into the short-term construction of a buffer solution - the International Planetary Sunshade (IPSS). The IPSS system reduces solar irradiation mitigating the global mean temperature rise while offering a sustainable energy supply. The developement of the system poses multifaceted challenges only to be mastered by a collaboration of space agencies and private companies, while supported by society. Therefore, tackling the IPSS within international roadmaps is essential to exploit synergies, shorten development time, and promote international cooperation. An evolutionary concept achieves stepwise Earth independence by utilizing lunar resources. The feasibility of the IPSS also depends on the foil’s supporting structure. Therefore, a lightweight manufacturing technology that meets several criteria, such as scalability, adaptivity, material compatibility, full automation, on-orbit manufacturing, in-situ resource utilization, and digital design including function integration, must be adopted. Hence, coreless filament winding (CFW) may be a suitable technology for realizing the demanded mass savings. The prerequisite for the superiority of CFW structures is an application- and material-compliant component and fiber net design. Previous experience with CFW cannot be directly transferred to the IPSS system due to the changed requirements for space application. This paper will present a systematic design concept for the IPSS, initially exploring a CFW support structure by discussing segmentation and modularity, proposing a new connection system, and implementing function integration.