TY  - JOUR
A1  - Thoma, Andreas
A1  - Gardi, Alessandro
A1  - Fisher, Alex
A1  - Braun, Carsten
T1  - Improving local path planning for UAV flight in challenging environments by refining cost function weights
JF  - CEAS Aeronautical Journal
N2  - Unmanned Aerial Vehicles (UAV) constantly gain in versatility. However, more reliable path planning algorithms are required until full autonomous UAV operation is possible. This work investigates the algorithm 3DVFH* and analyses its dependency on its cost function weights in 2400 environments. The analysis shows that the 3DVFH* can find a suitable path in every environment. However, a particular type of environment requires a specific choice of cost function weights. For minimal failure, probability interdependencies between the weights of the cost function have to be considered. This dependency reduces the number of control parameters and simplifies the usage of the 3DVFH*. Weights for costs associated with vertical evasion (pitch cost) and vicinity to obstacles (obstacle cost) have the highest influence on the failure probability of the local path planner. Environments with mainly very tall buildings (like large American city centres) require a preference for horizontal avoidance manoeuvres (achieved with high pitch cost weights). In contrast, environments with medium-to-low buildings (like European city centres) benefit from vertical avoidance manoeuvres (achieved with low pitch cost weights). The cost of the vicinity to obstacles also plays an essential role and must be chosen adequately for the environment. Choosing these two weights ideal is sufficient to reduce the failure probability below 10%.
KW  - Bio-inspired systems
KW  - Path planning
KW  - Obstacle avoidance
KW  - Unmanned aerial vehicles
Y1  - 2024
U6  - https://doi.org/10.1007/s13272-024-00741-x
SN  - 1869-5590 (eISSN)
SN  - 1869-5582
N1  - Corresponding author: Andreas Thoma
PB  - Springer
CY  - Wien
ER  - 
TY  - JOUR
A1  - Saretzki, Charlotte
A1  - Bergmann, Ole
A1  - Dahmann, Peter
A1  - Janser, Frank
A1  - Keimer, Jona
A1  - Machado, Patricia
A1  - Morrison, Audry
A1  - Page, Henry
A1  - Pluta, Emil
A1  - Stübing, Felix
A1  - Küpper, Thomas
T1  - Are small airplanes safe with regards to COVID-19 transmission?
JF  - Journal of Travel Medicine
Y1  - 2021
U6  - https://doi.org/10.1093/jtm/taab105
SN  - 1708-8305
VL  - 28
IS  - 7
PB  - Oxford University Press
CY  - Oxford
ER  - 
TY  - GEN
A1  - Mayntz, Joscha
A1  - Keimer, Jona
A1  - Tegtmeyer, Philipp
A1  - Dahmann, Peter
A1  - Hille, Sebastian
A1  - Stumpf, Eike
A1  - Fisher, Alex
A1  - Dorrington, Graham
T1  - Aerodynamic Investigation on Efficient Inflight Transition of a Propeller from Propulsion to Regeneration Mode
T2  - AIAA SCITECH 2022 Forum
N2  - This paper discusses a new way of inflight power regeneration for electric or hybrid-electric driven general aviation aircraft with one powertrain for both configurations. Three different approaches for the shift from propulsion to regeneration mode are analyzed. Numerical cal-culation and wind tunnel results are compared and show the highest regeneration potential for the "Windmill" approach, where the propeller blades are flipped, and rotation is reversed. A combination of all regeneration approaches for a realistic flight mission is discussed.
Y1  - 2021
U6  - https://doi.org/10.2514/6.2022-0546
N1  - AIAA SCITECH 2022 Forum, January 3-7, 2022, San Diego, CA & Virtual
PB  - AIAA
CY  - Reston, Va.
ER  - 
TY  - GEN
A1  - Keimer, Jona
A1  - Girbig, Leo
A1  - Mayntz, Joscha
A1  - Tegtmeyer, Philipp
A1  - Wendland, Frederik
A1  - Dahman, Peter
A1  - Fisher, Alex
A1  - Dorrington, Graham
T1  - Flight mission optimization for eco-efficiency in consideration of electric regeneration and atmospheric conditions
T2  - AIAA AVIATION 2022 Forum
N2  - The development and operation of hybrid or purely electrically powered aircraft in regional air mobility is a significant challenge for the entire aviation sector. This technology is expected to lead to substantial advances in flight performance, energy efficiency, reliability, safety, noise reduction, and exhaust emissions. Nevertheless, any consumed energy results in heat or carbon dioxide emissions and limited electric energy storage capabilities suppress commercial use. Therefore, the significant challenges to achieving eco-efficient aviation are increased aircraft efficiency, the development of new energy storage technologies, and the optimization of flight operations. Two major approaches for higher eco-efficiency are identified: The first one, is to take horizontal and vertical atmospheric motion phenomena into account. Where, in particular, atmospheric waves hold exciting potential. The second one is the use of the regeneration ability of electric aircraft. The fusion of both strategies is expected to improve efficiency. The objective is to reduce energy consumption during flight while not neglecting commercial usability and convenient flight characteristics. Therefore, an optimized control problem based on a general aviation class aircraft has to be developed and validated by flight experiments. The formulated approach enables a development of detailed knowledge of the potential and limitations of optimizing flight missions, considering the capability of regeneration and atmospheric influences to increase efficiency and range.
Y1  - 2022
U6  - https://doi.org/10.2514/6.2022-4118
N1  - AIAA AVIATION 2022 Forum, June 27-July 1, 2022 Chicago, IL & Virtual
PB  - AIAA
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Ulmer, Jessica
A1  - Braun, Sebastian
A1  - Cheng, Chi-Tsun
A1  - Dowey, Steve
A1  - Wollert, Jörg
T1  - A human factors-aware assistance system in manufacturing based on gamification and hardware modularisation
JF  - International Journal of Production Research
N2  - Assistance systems have been widely adopted in the manufacturing sector to facilitate various processes and tasks in production environments. However, existing systems are mostly equipped with rigid functional logic and do not provide individual user experiences or adapt to their capabilities. This work integrates human factors in assistance systems by adjusting the hardware and instruction presented to the workers’ cognitive and physical demands. A modular system architecture is designed accordingly, which allows a flexible component exchange according to the user and the work task. Gamification, the use of game elements in non-gaming contexts, has been further adopted in this work to provide level-based instructions and personalised feedback. The developed framework is validated by applying it to a manual workstation for industrial assembly routines.
KW  - Human factors
KW  - assistance system
KW  - gamification
KW  - adaptive systems
KW  - manufacturing
Y1  - 2023
U6  - https://doi.org/10.1080/00207543.2023.2166140
SN  - 0020-7543 (Print)
SN  - 1366-588X (Online)
PB  - Taylor & Francis
ER  - 
TY  - GEN
A1  - Machado, Patricia Almeida
A1  - Dahmann, Peter
A1  - Keimer, Jona
A1  - Saretzki, Charlotte
A1  - Stübing, Felix
A1  - Küpper, Thomas
T1  - Stress profile and individual workload monitoring in general aviation pilots – an experiment’s setting
T2  - 23. Annual Meeting of the German Society of Travel Medicine, Coburg, 18.-19.9.2020
Y1  - 2020
U6  - https://doi.org/10.55225/hppa.156
ER  - 
TY  - JOUR
A1  - Schopen, Oliver
A1  - Narayan, Sriram
A1  - Beckmann, Marvin
A1  - Najmi, Aezid-Ul-Hassan
A1  - Esch, Thomas
A1  - Shabani, Bahman
T1  - An EIS approach to quantify the effects of inlet air relative humidity on the performance of proton exchange membrane fuel cells: a pathway to developing a novel fault diagnostic method
JF  - International Journal of Hydrogen Energy
N2  - In this work, the effect of low air relative humidity on the operation of a polymer electrolyte membrane fuel cell is investigated. An innovative method through performing in situ electrochemical impedance spectroscopy is utilised to quantify the effect of inlet air relative humidity at the cathode side on internal ionic resistances and output voltage of the fuel cell. In addition, algorithms are developed to analyse the electrochemical characteristics of the fuel cell. For the specific fuel cell stack used in this study, the membrane resistance drops by over 39 % and the cathode side charge transfer resistance decreases by 23 % after increasing the humidity from 30 % to 85 %, while the results of static operation also show an increase of ∼2.2 % in the voltage output after increasing the relative humidity from 30 % to 85 %. In dynamic operation, visible drying effects occur at < 50 % relative humidity, whereby the increase of the air side stoichiometry increases the drying effects. Furthermore, other parameters, such as hydrogen humidification, internal stack structure, and operating parameters like stoichiometry, pressure, and temperature affect the overall water balance. Therefore, the optimal humidification range must be determined by considering all these parameters to maximise the fuel cell performance and durability. The results of this study are used to develop a health management system to ensure sufficient humidification by continuously monitoring the fuel cell polarisation data and electrochemical impedance spectroscopy indicators.
KW  - PEM fuel cell
KW  - Electrochemical impedance spectroscopy
KW  - Relative air humidity
KW  - Active humidity control
KW  - Impedance analysis
Y1  - 2024
SN  - 0360-3199 (print)
U6  - https://doi.org/10.1016/j.ijhydene.2024.01.218
SN  - 1879-3487 (online)
VL  - 58
IS  - 8
SP  - 1302
EP  - 1315
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Stark, Ralf
A1  - Rieping, Carla
A1  - Esch, Thomas
T1  - The impact of guide tubes on flow separation in rocket nozzles
T2  - Aerospace Europe Conference 2023 - 10th EUCASS - 9th CEAS
N2  - Rocket engine test facilities and launch pads are typically equipped with a guide tube. Its purpose is to ensure the controlled and safe routing of the hot exhaust gases. In addition, the guide tube induces a suction that effects the nozzle flow, namely the flow separation during transient start-up and shut-down of the engine. A cold flow subscale nozzle in combination with a set of guide tubes was studied experimentally
to determine the main influencing parameters.
KW  - Guide Tube
KW  - TICTOP
KW  - Nozzle
KW  - Suction
Y1  - 2023
N1  - Lausanne, July 9-13, 2023
ER  - 
TY  - CHAP
A1  - Stark, Ralf
A1  - Bartel, Sebastian
A1  - Ditsche, Florian
A1  - Esch, Thomas
T1  - Design study of a 30kN LOX/LCH4 aerospike rocket engine for lunar lander application
T2  - Aerospace Europe Conference 2023 - 10th EUCASS - 9th CEAS
N2  - Based on lunar lander concept EL3, various LOX/CH4 aerospike engines were studied. A distinction was made between single and cluster configurations as well as ideal and non-ideal contour concepts. It could be shown that non-ideal aerospike engines promise a significant payload gain.
Y1  - 2023
N1  - Lausanne, July 9-13, 2023
ER  - 
TY  - CHAP
A1  - Altherr, Lena
A1  - Döring, Bernd
A1  - Frauenrath, Tobias
A1  - Groß, Rolf
A1  - Mohan, Nijanthan
A1  - Oyen, Marc
A1  - Schnittcher, Lukas
A1  - Voß, Norbert
ED  - Reiff-Stephan, Jörg
ED  - Jäkel, Jens
ED  - Schwarz, André
T1  - DiggiTwin: ein interdisziplinäres Projekt zur Nutzung digitaler Zwillinge auf dem Weg zu einem klimaneutralen Gebäudebestand
T2  - Tagungsband AALE 2024 : Fit für die Zukunft: praktische Lösungen für die industrielle Automation
N2  - Im Hinblick auf die Klimaziele der Bundesrepublik Deutschland konzentriert sich das Projekt Diggi Twin auf die nachhaltige Gebäudeoptimierung. Grundlage für eine ganzheitliche Gebäudeüberwachung und -optimierung bildet dabei die Digitalisierung und Automation im Sinne eines Smart Buildings. Das interdisziplinäre Projekt der FH Aachen hat das Ziel, ein bestehendes Hochschulgebäude und einen Neubau an klimaneutrale Standards anzupassen. Im Rahmen des Projekts werden bekannte Verfahren, wie das Building Information Modeling (BIM), so erweitert, dass ein digitaler Gebäudezwilling entsteht. Dieser kann zur Optimierung des Gebäudebetriebs herangezogen werden, sowie als Basis für eine Erweiterung des Bewertungssystems Nachhaltiges Bauen (BNB) dienen. Mithilfe von Sensortechnologie und künstlicher Intelligenz kann so ein präzises Monitoring wichtiger Gebäudedaten erfolgen, um ungenutzte Energieeinsparpotenziale zu erkennen und zu nutzen. Das Projekt erforscht und setzt methodische Erkenntnisse zu BIM und digitalen Gebäudezwillingen praxisnah um, indem es spezifische Fragen zur Energie- und Ressourceneffizienz von Gebäuden untersucht und konkrete Lösungen für die Gebäudeoptimierung entwickelt.
KW  - Anomalieerkennung
KW  - IoT
KW  - Überwachung & Optimierung
KW  - DiggiTwin
KW  - BIM
KW  - Smart Building
KW  - Digitalisierung
Y1  - 2024
SN  - 978-3-910103-02-3
U6  - https://doi.org/10.33968/2024.67
N1  - 20. AALE-Konferenz. Bielefeld, 06.03.-08.03.2024
(Tagungsband unter https://doi.org/10.33968/2024.29)
SP  - 341
EP  - 346
PB  - le-tex publishing services GmbH
CY  - Leipzig
ER  -