@article{ThomaThomessenGardietal.2023, author = {Thoma, Andreas and Thomessen, Karolin and Gardi, Alessandro and Fisher, A. and Braun, Carsten}, title = {Prioritising paths: An improved cost function for local path planning for UAV in medical applications}, series = {The Aeronautical Journal}, journal = {The Aeronautical Journal}, number = {First View}, publisher = {Cambridge University Press}, address = {Cambridge}, issn = {0001-9240 (Print)}, doi = {10.1017/aer.2023.68}, pages = {1 -- 18}, year = {2023}, abstract = {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.}, language = {en} } @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{TrillaGrossenRobinsonetal.2008, author = {Trilla, Joan and Grossen, J{\"u}rgen and Robinson, Alexander and Funke, Harald and Bosschaerts, Walter and Hendrick, Patrick}, title = {Development of a hydrogen combustion chamber for an ultra micro gas turbine}, series = {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}, journal = {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}, pages = {101 -- 104}, year = {2008}, language = {en} } @article{UlmerBraunChengetal.2023, author = {Ulmer, Jessica and Braun, Carsten and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {A human factors-aware assistance system in manufacturing based on gamification and hardware modularisation}, series = {International Journal of Production Research}, journal = {International Journal of Production Research}, publisher = {Taylor \& Francis}, issn = {0020-7543 (Print)}, doi = {10.1080/00207543.2023.2166140}, year = {2023}, abstract = {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.}, 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} } @book{Wahle1998, author = {Wahle, Michael}, title = {Grundlagen der Maschinen- und Strukturdynamik. - (H{\"o}here Technische Mechanik ; 2)}, publisher = {Verl. Mainz}, address = {Aachen}, isbn = {3-89653-391-6}, pages = {216 S. : Ill.}, year = {1998}, language = {de} } @book{Wahle1998, author = {Wahle, Michael}, title = {Dynamik : Kinematik und Kinetik}, edition = {2. Aufl.}, publisher = {Verl. Mainz}, address = {Aachen}, isbn = {3-89653-390-8}, pages = {158 S. : graph. Darst.}, year = {1998}, 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} } @incollection{Wahle1997, author = {Wahle, Michael}, title = {Strukturmechanische Auslegung von Elastomer-Bauteilen in der Schwingungstechnik}, series = {Kolloquium anl{\"a}ßlich des 70. Geburtstags von H. {\"O}ry : [29.09.1997 - 30.09.1997, K{\´a}rm{\´a}n-Auditorium, H{\"o}rsaal FO5, RWTH Aachen]}, booktitle = {Kolloquium anl{\"a}ßlich des 70. Geburtstags von H. {\"O}ry : [29.09.1997 - 30.09.1997, K{\´a}rm{\´a}n-Auditorium, H{\"o}rsaal FO5, RWTH Aachen]}, editor = {Reimerdes, Hans-G.}, publisher = {Inst. f{\"u}r Leichtbau}, address = {Aachen}, pages = {175 -- 188}, year = {1997}, language = {de} } @inproceedings{Wahle1987, author = {Wahle, Michael}, title = {Optimale Auslegung von Schwingungsd{\"a}mpfern zur Schwingungsberuhigung elastischer Strukturen}, series = {D{\"a}mpfung von Schwingungen bei Maschinen und Bauwerken : Tagung N{\"u}rnberg, 9. u. 10. April 1987. - (VDI-Berichte ; 627)}, booktitle = {D{\"a}mpfung von Schwingungen bei Maschinen und Bauwerken : Tagung N{\"u}rnberg, 9. u. 10. April 1987. - (VDI-Berichte ; 627)}, publisher = {VDI-Verl.}, address = {D{\"u}sseldorf}, isbn = {3-18-090627-8}, pages = {355 -- 373}, year = {1987}, language = {de} }