TY - JOUR A1 - Thoma, Andreas A1 - Thomessen, Karolin A1 - Gardi, Alessandro A1 - Fisher, A. A1 - Braun, Carsten T1 - Prioritising paths: An improved cost function for local path planning for UAV in medical applications JF - The Aeronautical Journal N2 - Even the shortest flight through unknown, cluttered environments requires reliable local path planning algorithms to avoid unforeseen obstacles. The algorithm must evaluate alternative flight paths and identify the best path if an obstacle blocks its way. Commonly, weighted sums are used here. This work shows that weighted Chebyshev distances and factorial achievement scalarising functions are suitable alternatives to weighted sums if combined with the 3DVFH* local path planning algorithm. Both methods considerably reduce the failure probability of simulated flights in various environments. The standard 3DVFH* uses a weighted sum and has a failure probability of 50% in the test environments. A factorial achievement scalarising function, which minimises the worst combination of two out of four objective functions, reaches a failure probability of 26%; A weighted Chebyshev distance, which optimises the worst objective, has a failure probability of 30%. These results show promise for further enhancements and to support broader applicability. KW - Path planning KW - Cost function KW - Multi-objective optimization Y1 - 2023 U6 - http://dx.doi.org/10.1017/aer.2023.68 SN - 0001-9240 (Print) SN - 2059-6464 (Online) IS - First View SP - 1 EP - 18 PB - Cambridge University Press CY - Cambridge ER - TY - JOUR A1 - Thomessen, Karolin A1 - Thoma, Andreas A1 - Braun, Carsten T1 - Bio-inspired altitude changing extension to the 3DVFH* local obstacle avoidance algorithm JF - CEAS Aeronautical Journal N2 - 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. KW - UAV KW - Obstacle avoidance KW - Autonomy KW - Local path planning Y1 - 2023 U6 - http://dx.doi.org/10.1007/s13272-023-00691-w SN - 1869-5590 (Online) SN - 1869-5582 (Print) N1 - Corresponding author: Karolin Thomessen PB - Springer CY - Wien ER - TY - JOUR A1 - Trilla, Joan A1 - Grossen, Jürgen A1 - Robinson, Alexander A1 - Funke, Harald A1 - Bosschaerts, Walter A1 - Hendrick, Patrick T1 - Development of a hydrogen combustion chamber for an ultra micro gas turbine JF - PowerMEMS 2008, 8th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications, microEMS 2008, 2nd Symposium on Micro Environmental Machine Systems, Sendai, JP, Nov 9-12, 2008 Y1 - 2008 SP - 101 EP - 104 ER - TY - JOUR A1 - Ulmer, Jessica A1 - Braun, Carsten 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 - http://dx.doi.org/10.1080/00207543.2023.2166140 SN - 0020-7543 (Print) SN - 1366-588X (Online) PB - Taylor & Francis ER - TY - CHAP A1 - Veettil, Yadu Krishna Morassery A1 - Rakshit, Shantam A1 - Schopen, Oliver A1 - Kemper, Hans A1 - Esch, Thomas A1 - Shabani, Bahman ED - Bin Abdollah, Mohd Fadzli ED - Amiruddin, Hilmi ED - Singh, Amrik Singh Phuman ED - Munir, Fudhail Abdul ED - Ibrahim, Asriana T1 - Automated Control System Strategies to Ensure Safety of PEM Fuel Cells Using Kalman Filters T2 - Proceedings of the 7th International Conference and Exhibition on Sustainable Energy and Advanced Materials (ICE-SEAM 2021), Melaka, Malaysia N2 - 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. KW - control system KW - PEM fuel cells KW - Kalman filter Y1 - 2022 SN - 978-981-19-3178-9 SN - 978-981-19-3179-6 (E-Book) U6 - http://dx.doi.org/10.1007/978-981-19-3179-6_55 SN - 2195-4356 N1 - The 7th International Conference and Exhibition on Sustainable Energy and Advanced Material (ICE-SEAM 2021) was organized by Universiti Teknikal Malaysia Melaka (UTeM), Malaysia, in association with the Universitas Sebelas Maret (UNS), Indonesia, on 23 November 2021 SP - 296 EP - 299 PB - Springer Nature CY - Singapore ER - TY - BOOK A1 - Wahle, Michael T1 - Grundlagen der Maschinen- und Strukturdynamik. - (Höhere Technische Mechanik ; 2) Y1 - 1998 SN - 3-89653-391-6 N1 - 2. Aufl. PB - Verl. Mainz CY - Aachen ER - TY - BOOK A1 - Wahle, Michael T1 - Dynamik : Kinematik und Kinetik Y1 - 1998 SN - 3-89653-390-8 N1 - Die zwei Bände der ersten Auflage in einem Band. PB - Verl. Mainz CY - Aachen ET - 2. Aufl. ER - TY - JOUR A1 - Wahle, Michael T1 - Auf sicheren Füßen stehen : Entwicklung eines Maschinenlagers mit einem Federkern aus zelligem Polyurethan JF - Der Konstrukteur Y1 - 2000 SN - 0344-4570 VL - 31 IS - 6 SP - 30 EP - 32 ER - TY - CHAP A1 - Wahle, Michael ED - Reimerdes, Hans-G. T1 - Strukturmechanische Auslegung von Elastomer-Bauteilen in der Schwingungstechnik T2 - Kolloquium anläßlich des 70. Geburtstags von H. Öry : [29.09.1997 - 30.09.1997, Kármán-Auditorium, Hörsaal FO5, RWTH Aachen] Y1 - 1997 SP - 175 EP - 188 PB - Inst. für Leichtbau CY - Aachen ER - TY - CHAP A1 - Wahle, Michael T1 - Optimale Auslegung von Schwingungsdämpfern zur Schwingungsberuhigung elastischer Strukturen T2 - Dämpfung von Schwingungen bei Maschinen und Bauwerken : Tagung Nürnberg, 9. u. 10. April 1987. - (VDI-Berichte ; 627) Y1 - 1987 SN - 3-18-090627-8 SP - 355 EP - 373 PB - VDI-Verl. CY - Düsseldorf ER - TY - THES A1 - Wahle, Michael T1 - Beitrag zur passiven Kontrolle schwach gedämpfter elastischer Strukturen mittels dynamischer Schwingungsdämpfer Y1 - 1985 N1 - Aachen, Techn. Hochsch., Diss., 1984 ER - TY - CHAP A1 - Wahle, Michael T1 - Calculation of the response of heat exchanger tubes with regard to nonlinear and prestressing effects T2 - Vibration in nuclear plant : proceedings of the 3rd International Conference on Vibration in Nuclear Plant held on 11 - 14 May 1982, Keswick ; vol. 1 Y1 - 1983 SN - 0-7277-0192-4 (Druckausg.) SN - 978-0-7277-5270-3 (E-Book) N1 - International Conference on Vibration in Nuclear Plant <3, 1982, Keswick> N1 - Paper 1.10 (Log No. 71) SP - 162 EP - 183 PB - British Nuclear Energy Society CY - London ER - TY - BOOK A1 - Wahle, Michael T1 - Angewandte Strukturanalyse. - (Dynamik) Y1 - 1999 SN - 3-89653-567-6 PB - Mainz CY - Aachen ER - TY - BOOK A1 - Wahle, Michael T1 - Grundlagen der Maschinen- und Strukturdynamik. - (Höhere Technische Mechanik ; 2) Y1 - 1995 SN - 3-930911-61-2 PB - Mainz CY - Aachen ET - 1. Aufl. ER - TY - BOOK A1 - Wahle, Michael T1 - Kinetik. - (Dynamik ; 2) Y1 - 1994 SN - 3- 930085-94-1 PB - Mainz CY - Aachen ET - 1. Aufl. ER - TY - BOOK A1 - Wahle, Michael T1 - Kinematik. - (Dynamik ; 1) Y1 - 1993 SN - 3-930085-25-9 PB - Mainz CY - Aachen ET - 1. Aufl. ER - TY - CHAP A1 - Wahle, Michael T1 - Determination of flow induced nonlinear vibrations of prestressed heat exchanger tubes T2 - Advanced Course in Heat Exchangers : Theory and Practice ; ICHMT Symposium ; Dubrovnik, Croatia 1981. - (ICHMT digital library online ; 19) Y1 - 1983 SP - 339 EP - 353 PB - Begell House CY - Redding, Connecticut ER - TY - PAT A1 - Wahle, Michael T1 - Stoßdämpfer : Offenlegungschrift / Europäische Patentschrift T1 - Shock absorber : patent of invention Y1 - 1994 PB - Deutsches Patent- und Markenamt / Europäisches Patentamt CY - München / Den Hague ER - TY - PAT A1 - Wahle, Michael T1 - Anordnung zum Dämpfen von Schwingungen elastischer Systeme : Offenlegungsschrift / Europäische Patentschrift T1 - Arrangement for damping oscillations in elastic systems : patent of invention Y1 - 1990 PB - Deutsches Patent- und Markenamt / Europäisches Patentamt CY - München / Den Hague ER - TY - PAT A1 - Wahle, Michael T1 - Gestaltung von plattenförmigen Hohlprofilen oder wellblechartigen Profilen : Offenlegungsschrift / Europäische Patentschrift T1 - Configuration of panel-shaped hollow profiles : patent of invention Y1 - 1989 PB - Deutsches Patent- und Markenamt / Europäisches Patentamt CY - München / Den Hague ER -