@article{ThomessenThomaBraun2023, author = {Thomessen, Karolin and Thoma, Andreas and Braun, Carsten}, title = {Bio-inspired altitude changing extension to the 3DVFH* local obstacle avoidance algorithm}, series = {CEAS Aeronautical Journal}, journal = {CEAS Aeronautical Journal}, publisher = {Springer}, address = {Wien}, issn = {1869-5590 (Online)}, doi = {10.1007/s13272-023-00691-w}, pages = {11 Seiten}, year = {2023}, abstract = {Obstacle avoidance is critical for unmanned aerial vehicles (UAVs) operating autonomously. Obstacle avoidance algorithms either rely on global environment data or local sensor data. Local path planners react to unforeseen objects and plan purely on local sensor information. Similarly, animals need to find feasible paths based on local information about their surroundings. Therefore, their behavior is a valuable source of inspiration for path planning. Bumblebees tend to fly vertically over far-away obstacles and horizontally around close ones, implying two zones for different flight strategies depending on the distance to obstacles. This work enhances the local path planner 3DVFH* with this bio-inspired strategy. The algorithm alters the goal-driven function of the 3DVFH* to climb-preferring if obstacles are far away. Prior experiments with bumblebees led to two definitions of flight zone limits depending on the distance to obstacles, leading to two algorithm variants. Both variants reduce the probability of not reaching the goal of a 3DVFH* implementation in Matlab/Simulink. The best variant, 3DVFH*b-b, reduces this probability from 70.7 to 18.6\% in city-like worlds using a strong vertical evasion strategy. Energy consumption is higher, and flight paths are longer compared to the algorithm version with pronounced horizontal evasion tendency. A parameter study analyzes the effect of different weighting factors in the cost function. The best parameter combination shows a failure probability of 6.9\% in city-like worlds and reduces energy consumption by 28\%. Our findings demonstrate the potential of bio-inspired approaches for improving the performance of local path planning algorithms for UAV.}, language = {en} } @article{BlomePriester1991, author = {Blome, Hans-Joachim and Priester, W.}, title = {Big Bounce in the very early Universe}, series = {Astronomy and Astrophysics. 250 (1991), H. 1}, journal = {Astronomy and Astrophysics. 250 (1991), H. 1}, isbn = {0004-6361}, pages = {43 -- 49}, year = {1991}, language = {en} } @book{Ley1982, author = {Ley, Wilfried}, title = {Bewertung von Solarkollektormessungen unter natuerlichen und simulierten Bedingungen}, publisher = {Inst. f. Raumsimulation}, address = {K{\"o}ln}, pages = {190 Seiten, 133 Bilder, 19 Tabellen, 43 Quellen}, year = {1982}, language = {de} } @techreport{Rosenkranz1989, author = {Rosenkranz, Josef}, title = {Ber{\"u}cksichtigung des Einflusses von Gleitlagergeh{\"a}usen auf das dynamische Verhalten von Rotoren : Abschlußbericht : Forschungsvorhaben Nr. 128 "Gleitlagergeh{\"a}usesteifigkeit" ; Berichtszeitraum 1985-1988. - (Forschungsheft / Forschungsvereinigung Antriebstechnik e.V. ; 303)}, publisher = {FVA}, address = {Frankfurt am Main}, pages = {70 S : Ill., graph. Darst}, year = {1989}, language = {de} } @article{PeekenRosenkranzSchelenz1991, author = {Peeken, Heinz and Rosenkranz, Josef and Schelenz, R.}, title = {Ber{\"u}cksichtigung des Einflusses der Gleitlagergeh{\"a}usesteifigkeit auf das dynamische Verhalten von Rotoren}, series = {Antriebstechnik : Organ der Forschungsvereinigung Antriebstechnik e.V.}, volume = {30}, journal = {Antriebstechnik : Organ der Forschungsvereinigung Antriebstechnik e.V.}, number = {9}, issn = {0341-2652}, pages = {71 -- 75}, year = {1991}, language = {de} } @article{Gerhardt1986, author = {Gerhardt, Hans Joachim}, title = {Belastung von Rauchabzugsgeraeten bei Windangriff}, series = {Sanitaer- und Heizungstechnik. 51 (1986), H. 3}, journal = {Sanitaer- und Heizungstechnik. 51 (1986), H. 3}, isbn = {0036-4401}, pages = {150 -- 152}, year = {1986}, language = {de} } @article{GerhardtKramer1984, author = {Gerhardt, Hans Joachim and Kramer, C.}, title = {Belastung von RA bei Windangriff}, series = {Zentralblatt fuer Industriebau. 30 (1984), H. 3}, journal = {Zentralblatt fuer Industriebau. 30 (1984), H. 3}, isbn = {0044-4227}, pages = {214 -- 217}, year = {1984}, language = {de} } @phdthesis{Wahle1985, author = {Wahle, Michael}, title = {Beitrag zur passiven Kontrolle schwach ged{\"a}mpfter elastischer Strukturen mittels dynamischer Schwingungsd{\"a}mpfer}, pages = {XIV, 305 S. : Ill., zahlr. graph. Darst.}, year = {1985}, language = {de} } @article{ChristenBarteltKowalski2010, author = {Christen, Marc and Bartelt, Perry and Kowalski, Julia}, title = {Back calculation of the In den Arelen avalanche with RAMMS: Interpretation of model results}, series = {Annals of Glaciology}, volume = {51}, journal = {Annals of Glaciology}, number = {54}, publisher = {Cambridge University Press}, address = {Cambridge}, isbn = {1727-5644}, doi = {10.3189/172756410791386553}, pages = {161 -- 168}, year = {2010}, abstract = {Two- and three-dimensional avalanche dynamics models are being increasingly used in hazard-mitigation studies. These models can provide improved and more accurate results for hazard mapping than the simple one-dimensional models presently used in practice. However, two- and three-dimensional models generate an extensive amount of output data, making the interpretation of simulation results more difficult. To perform a simulation in three-dimensional terrain, numerical models require a digital elevation model, specification of avalanche release areas (spatial extent and volume), selection of solution methods, finding an adequate calculation resolution and, finally, the choice of friction parameters. In this paper, the importance and difficulty of correctly setting up and analysing the results of a numerical avalanche dynamics simulation is discussed. We apply the two-dimensional simulation program RAMMS to the 1968 extreme avalanche event In den Arelen. We show the effect of model input variations on simulation results and the dangers and complexities in their interpretation.}, language = {en} } @article{LaarmannThomaMischetal.2023, author = {Laarmann, Lukas and Thoma, Andreas and Misch, Philipp and R{\"o}th, Thilo and Braun, Carsten and Watkins, Simon and Fard, Mohammad}, title = {Automotive safety approach for future eVTOL vehicles}, series = {CEAS Aeronautical Journal}, journal = {CEAS Aeronautical Journal}, publisher = {Springer Nature}, issn = {1869-5590 (Online)}, doi = {10.1007/s13272-023-00655-0}, pages = {11 Seiten}, year = {2023}, abstract = {The eVTOL industry is a rapidly growing mass market expected to start in 2024. eVTOL compete, caused by their predicted missions, with ground-based transportation modes, including mainly passenger cars. Therefore, the automotive and classical aircraft design process is reviewed and compared to highlight advantages for eVTOL development. A special focus is on ergonomic comfort and safety. The need for further investigation of eVTOL's crashworthiness is outlined by, first, specifying the relevance of passive safety via accident statistics and customer perception analysis; second, comparing the current state of regulation and certification; and third, discussing the advantages of integral safety and applying the automotive safety approach for eVTOL development. Integral safety links active and passive safety, while the automotive safety approach means implementing standardized mandatory full-vehicle crash tests for future eVTOL. Subsequently, possible crash impact conditions are analyzed, and three full-vehicle crash load cases are presented.}, language = {en} } @phdthesis{Polaczek1995, author = {Polaczek, Christa}, title = {Automatische 3-dimensionale FEM-Netzgenerierung f{\"u}r die Formf{\"u}ll- und Erstarrungssimulation. - (Fortschrittberichte VDI : Reihe 20, Rechnerunterst{\"u}tzte Verfahren ; 182)}, number = {Als Ms. gedr.}, publisher = {VDI-Verl.}, address = {D{\"u}sseldorf}, isbn = {3-18-318220-3}, pages = {VII, 131 S. : Ill., graph. Darst.}, year = {1995}, language = {de} } @article{SchmitzOligschlaegerEifleretal.1994, author = {Schmitz, G{\"u}nter and Oligschl{\"a}ger, U. and Eifler, G. and Lechner, H.}, title = {Automated System for Optimized Calibration of Engine Management Systems}, year = {1994}, language = {en} } @article{NeuJanserKhatibietal.2016, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {Automated modal parameter-based anomaly detection under varying wind excitation}, series = {Structural Health Monitoring}, volume = {15}, journal = {Structural Health Monitoring}, number = {6}, publisher = {Sage}, address = {London}, issn = {1475-9217}, doi = {10.1177/1475921716665803}, pages = {1 -- 20}, year = {2016}, abstract = {Wind-induced operational variability is one of the major challenges for structural health monitoring of slender engineering structures like aircraft wings or wind turbine blades. Damage sensitive features often show an even bigger sensitivity to operational variability. In this study a composite cantilever was subjected to multiple mass configurations, velocities and angles of attack in a controlled wind tunnel environment. A small-scale impact damage was introduced to the specimen and the structural response measurements were repeated. The proposed damage detection methodology is based on automated operational modal analysis. A novel baseline preparation procedure is described that reduces the amount of user interaction to the provision of a single consistency threshold. The procedure starts with an indeterminate number of operational modal analysis identifications from a large number of datasets and returns a complete baseline matrix of natural frequencies and damping ratios that is suitable for subsequent anomaly detection. Mahalanobis distance-based anomaly detection is then applied to successfully detect the damage under varying severities of operational variability and with various degrees of knowledge about the present operational conditions. The damage detection capabilities of the proposed methodology were found to be excellent under varying velocities and angles of attack. Damage detection was less successful under joint mass and wind variability but could be significantly improved through the provision of the currently encountered operational conditions.}, language = {en} } @inproceedings{AyedStrieganKustereretal.2017, author = {Ayed, Anis Haj and Striegan, Constantin J. D. and Kusterer, Karsten and Funke, Harald and Kazari, M. and Horikawa, Atsushi and Okada, Kunio}, title = {Automated design space exploration of the hydrogen fueled "Micromix" combustor technology}, pages = {1 -- 8}, year = {2017}, abstract = {Combined with the use of renewable energy sources for its production, Hydrogen represents a possible alternative gas turbine fuel for future low emission power generation. Due to its different physical properties compared to other fuels such as natural gas, well established gas turbine combustion systems cannot be directly applied for Dry Low NOx (DLN) Hydrogen combustion. This makes the development of new combustion technologies an essential and challenging task for the future of hydrogen fueled gas turbines. The newly developed and successfully tested "DLN Micromix" combustion technology offers a great potential to burn hydrogen in gas turbines at very low NOx emissions. Aiming to further develop an existing burner design in terms of increased energy density, a redesign is required in order to stabilise the flames at higher mass flows and to maintain low emission levels. For this purpose, a systematic design exploration has been carried out with the support of CFD and optimisation tools to identify the interactions of geometrical and design parameters on the combustor performance. Aerodynamic effects as well as flame and emission formation are observed and understood time- and cost-efficiently. Correlations between single geometric values, the pressure drop of the burner and NOx production have been identified as a result. This numeric methodology helps to reduce the effort of manufacturing and testing to few designs for single validation campaigns, in order to confirm the flame stability and NOx emissions in a wider operating condition field.}, language = {en} } @inproceedings{VeettilRakshitSchopenetal.2022, author = {Veettil, Yadu Krishna Morassery and Rakshit, Shantam and Schopen, Oliver and Kemper, Hans and Esch, Thomas and Shabani, Bahman}, title = {Automated Control System Strategies to Ensure Safety of PEM Fuel Cells Using Kalman Filters}, series = {Proceedings of the 7th International Conference and Exhibition on Sustainable Energy and Advanced Materials (ICE-SEAM 2021), Melaka, Malaysia}, booktitle = {Proceedings of the 7th International Conference and Exhibition on Sustainable Energy and Advanced Materials (ICE-SEAM 2021), Melaka, Malaysia}, editor = {Bin Abdollah, Mohd Fadzli and Amiruddin, Hilmi and Singh, Amrik Singh Phuman and Munir, Fudhail Abdul and Ibrahim, Asriana}, publisher = {Springer Nature}, address = {Singapore}, isbn = {978-981-19-3178-9}, issn = {2195-4356}, doi = {10.1007/978-981-19-3179-6_55}, pages = {296 -- 299}, year = {2022}, abstract = {Having well-defined control strategies for fuel cells, that can efficiently detect errors and take corrective action is critically important for safety in all applications, and especially so in aviation. The algorithms not only ensure operator safety by monitoring the fuel cell and connected components, but also contribute to extending the health of the fuel cell, its durability and safe operation over its lifetime. While sensors are used to provide peripheral data surrounding the fuel cell, the internal states of the fuel cell cannot be directly measured. To overcome this restriction, Kalman Filter has been implemented as an internal state observer. Other safety conditions are evaluated using real-time data from every connected sensor and corrective actions automatically take place to ensure safety. The algorithms discussed in this paper have been validated thorough Model-in-the-Loop (MiL) tests as well as practical validation at a dedicated test bench.}, language = {en} } @incollection{HirschWahle1978, author = {Hirsch, G. and Wahle, Michael}, title = {Auslegungskriterien f{\"u}r Dynamische Schwingungsd{\"a}mpfer f{\"u}r schwach ged{\"a}mpfte elastische Strukturen unter Ber{\"u}cksichtigung einer der Masseverteilung nicht proportionalen Zusatzd{\"a}mpfung}, series = {Hans Ebner : Ged{\"a}chtnis-Kolloquium am 27./28. Oktober 1977 in Aachen. - (Mitteilung aus dem Institut f{\"u}r Leichtbau, Aachen ; 1)}, booktitle = {Hans Ebner : Ged{\"a}chtnis-Kolloquium am 27./28. Oktober 1977 in Aachen. - (Mitteilung aus dem Institut f{\"u}r Leichtbau, Aachen ; 1)}, address = {Aachen}, pages = {374 -- 400}, year = {1978}, language = {de} } @inproceedings{PflugWahle1994, author = {Pflug, J. and Wahle, Michael}, title = {Auslegung der CFK-Sandwich-Rumpfstruktur eines Hubschraubers mit der Methode der Finiten Elemente}, series = {Basistechnologien f{\"u}r neue Herausforderungen in der Luft- und Raumfahrt : DGLR-Jahrestagung / Deutscher Luft- und Raumfahrt-Kongress 1994, Erlangen, 04.- 07. Oktober 1994. - (Jahrbuch der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt ; 1994,3)}, booktitle = {Basistechnologien f{\"u}r neue Herausforderungen in der Luft- und Raumfahrt : DGLR-Jahrestagung / Deutscher Luft- und Raumfahrt-Kongress 1994, Erlangen, 04.- 07. Oktober 1994. - (Jahrbuch der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt ; 1994,3)}, editor = {B{\"u}rger, Gudrun}, publisher = {DGLR}, address = {Bonn}, pages = {1135 -- 1144}, year = {1994}, language = {de} } @misc{SchmitzSchebitzEsch1997, author = {Schmitz, G{\"u}nter and Schebitz, Michael and Esch, Thomas}, title = {Aus der Ruhelage selbstanziehender elektromagnetischer Aktuator}, year = {1997}, abstract = {Elektromagnetischer Aktuator zur Bet{\"a}tigung eines Stellgliedes (2), mit wenigstens einem Elektromagneten (4) und einem mit dem Stellglied (2) verbundenen Anker (3), der gegen die Kraft einer R{\"u}ckstellfeder (6) aus seiner Ruhelage in Richtung auf den Elektromagneten (4) bewegbar ist, mit einer R{\"u}ckstellfeder (6), die eine nicht lineare, bezogen auf die Ruhelage des Ankers (3) progressiv ansteigende Kennlinie aufweist.}, language = {de} } @article{Wahle2000, author = {Wahle, Michael}, title = {Auf sicheren F{\"u}ßen stehen : Entwicklung eines Maschinenlagers mit einem Federkern aus zelligem Polyurethan}, series = {Der Konstrukteur}, volume = {31}, journal = {Der Konstrukteur}, number = {6}, isbn = {0344-4570}, pages = {30 -- 32}, year = {2000}, language = {de} } @inproceedings{PirovanoSeefeldtDachwaldetal.2015, author = {Pirovano, Laura and Seefeldt, Patric and Dachwald, Bernd and Noomen, Ron}, title = {Attitude and orbital modeling of an uncontrolled solar-sail experiment in low-Earth orbit}, series = {25th International Symposium on Space Flight Dynamics ISSFD}, booktitle = {25th International Symposium on Space Flight Dynamics ISSFD}, pages = {1 -- 15}, year = {2015}, abstract = {Gossamer-1 is the first project of the three-step Gossamer roadmap, the purpose of which is to develop, prove and demonstrate that solar-sail technology is a safe and reliable propulsion technique for long-lasting and high-energy missions. This paper firstly presents the structural analysis performed on the sail to understand its elastic behavior. The results are then used in attitude and orbital simulations. The model considers the main forces and torques that a satellite experiences in low-Earth orbit coupled with the sail deformation. Doing the simulations for varying initial conditions in attitude and rotation rate, the results show initial states to avoid and maximum rotation rates reached for correct and faulty deployment of the sail. Lastly comparisons with the classic flat sail model are carried out to test the hypothesis that the elastic behavior does play a role in the attitude and orbital behavior of the sail}, language = {en} }