TY - GEN A1 - Assafo, Maryam A1 - Städter, Jost Philipp A1 - Meisel, Tenia A1 - Langendörfer, Peter T1 - On the Stability and Homogeneous Ensemble of Feature Selection for Predictive Maintenance: A Classification Application for Tool Condition Monitoring in Milling T2 - Sensors N2 - Feature selection (FS) represents an essential step for many machine learning-based predictive maintenance (PdM) applications, including various industrial processes, components, and monitoring tasks. The selected features not only serve as inputs to the learning models but also can influence further decisions and analysis, e.g., sensor selection and understandability of the PdM system. Hence, before deploying the PdM system, it is crucial to examine the reproducibility and robustness of the selected features under variations in the input data. This is particularly critical for real-world datasets with a low sample-to-dimension ratio (SDR). However, to the best of our knowledge, stability of the FS methods under data variations has not been considered yet in the field of PdM. This paper addresses this issue with an application to tool condition monitoring in milling, where classifiers based on support vector machines and random forest were employed. We used a five-fold cross-validation to evaluate three popular filter-based FS methods, namely Fisher score, minimum redundancy maximum relevance (mRMR), and ReliefF, in terms of both stability and macro-F1. Further, for each method, we investigated the impact of the homogeneous FS ensemble on both performance indicators. To gain broad insights, we used four (2:2) milling datasets obtained from our experiments and NASA’s repository, which differ in the operating conditions, sensors, SDR, number of classes, etc. For each dataset, the study was conducted for two individual sensors and their fusion. Among the conclusions: (1) Different FS methods can yield comparable macro-F1 yet considerably different FS stability values. (2) Fisher score (single and/or ensemble) is superior in most of the cases. (3) mRMR’s stability is overall the lowest, the most variable over different settings (e.g., sensor(s), subset cardinality), and the one that benefits the most from the ensemble. KW - classification KW - feature selection KW - homogeneous feature selection ensemble KW - predictive maintenance KW - milling KW - sensor fusion KW - stability of feature selection KW - tool condition monitoring Y1 - 2023 U6 - https://doi.org/10.3390/s23094461 SN - 1424-8220 VL - 23 IS - 9 ER - TY - GEN A1 - Berger, Ulrich A1 - Halbauer, Marcel A1 - Lehmann, Christian A1 - Städter, Jost Philipp T1 - Präzisionsfräsen mit Industrierobotern – Strategien zur Reduzierung und Kompensation von durch Prozesskräften verursachte Genauigkeits-, Positionier- und Fertigungstoleranzabweichungen T2 - Zeitschrift für wirtschaftlichen Fabrikbetrieb - ZWF Y1 - 2012 SN - 0947-0085 VL - 107 IS - 7-8 SP - 533 EP - 536 ER - TY - CHAP A1 - Berger, Ulrich A1 - Le, Duc Tho A1 - Zou, Wenchao A1 - Lehmann, Christian A1 - Städter, Jost Philipp ED - Car, Zlatan T1 - Development of a mobile robot system for assembly task on continuous conveyor T2 - Proceedings, International Conference on Innovative Technologies, IN-TECH 2015, Dubrovnik, Croatia, 09. - 11.09.2015 N2 - This paper presents a novel approach for automated smart factory based on the ideas of Internet of Things (IoT) and the usage of mobile technology of the german „Industry 4.0“ [6]. IoT enables the achievement of greater value and service by exchanging data between different devices and the manufacturer. The data collected from all devices will be exchanged via wireless networks. Mobile technology can be used to cover non value-added processes [3] i.e. transportation in the manufacturing. By combining transportation tasks and value adding production steps, waste of production time, cost and effort can be reduced. This paper presents the first step toward this approach [7]: the mobile robot moves alongside the moving object and executes the manufacturing tasks during its transportation. For the demonstration of the developed solution a mobile platform and an optical measurement system was used. The synchronization between the mobile platform and the object will be experimentally tested. Consequently the results will demonstrate how the mobile robot is able to follow the moving object. Y1 - 2015 SP - 331 EP - 334 PB - Fac. of Engineering, Univ. of Rijeka CY - Rijeka ER - TY - CHAP A1 - Haage, Mathias A1 - Halbauer, Marcel A1 - Lehmann, Christian A1 - Städter, Jost Philipp T1 - Increasing Robotic Machining Accuracy Using Offline Compensation Based on Joint-Motion Simulation T2 - Proceedings for the joint conference of ISR 2014, 45th International Symposium on Robotics, Robotik 2014, 8th German Conference on Robotics, 2 - 3 June 2014 parallel to Automatica Y1 - 2014 SN - 978-3-8007-3601-0 SP - 347 EP - 354 PB - VDE-Verlag CY - Berlin [u.a.] ER - TY - CHAP A1 - Halbauer, Marcel A1 - Lehmann, Christian A1 - Städter, Jost Philipp A1 - Berger, Ulrich T1 - Servicerobotik zum Handhaben biegeschlaffer Teile mittels Tiefenbildsensor T2 - Automation 2013, 14. Branchentreff der Mess- und Automatisierungstechnik, Kongresshaus Baden-Baden, 25. und 26. Juni 2013 Y1 - 2013 SN - 978-3-18-092209-6 SP - 113 EP - 116 PB - VDI Verlag CY - Düsseldorf ER - TY - CHAP A1 - Halbauer, Marcel A1 - Lehmann, Christian A1 - Städter, Jost Philipp A1 - Berger, Ulrich A1 - Leali, Francesco T1 - Milling strategies optimized for industrial robots to machine hard materials T2 - 2013 IEEE 18th Conference on Emerging Technologies & Factory Automation (ETFA 2013), Cagliari, Italy, 10 - 13 September 2013, vol. 1 Y1 - 2013 SP - 375 EP - 378 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Le, Duc Tho A1 - Andulkar, Mayur A1 - Zou, Wenchao A1 - Städter, Jost Philipp A1 - Berger, Ulrich T1 - Self adaptive system for flexible robot assembly operation T2 - Self adaptive system for flexible robot assembly operation, Emerging Technologies and Factory Automation (ETFA), 2016 IEEE 21st International Conference on, 2016 N2 - In this paper a flexible robot system for assembly operations in a semi structured environment is proposed. The system uses a moveable robot equipped with an arbitrarily mounted 3D camera and a 2D camera on the robot gripper for accurate object detection. The system is developed based on the Robot Operating System (ROS) and uses the state of the art trajectory planner MoveIt for collision free robot motion planning. The object recognition for the system is performed using a combination of the two camera's and robot end effector and the deviation of objects in the robot workspace is found to be in the range of 2.2 mm along X and Y axes. Furthermore, an implementation procedure of the proposed system for assembly task is explained. Y1 - 2017 SN - 978-1-5090-1314-2 U6 - https://doi.org/10.1109/ETFA.2016.7733544 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Lehmann, Christian A1 - Berger, Ulrich A1 - Städter, Jost Philipp ED - Vogel-Heuser, Birgit ED - Bauernhansl, Thomas ED - Hompel, Michael T1 - Anwendungsbeispiele zur Integration heterogener Steuerungssysteme bei robotergestützten Industrieanlagen T2 - Handbuch Industrie 4.0 : Produktion, Automatisierung und Logistik Y1 - 2016 SN - 978-3-662-45537-1 U6 - https://doi.org/10.1007/978-3-662-45537-1_49-1 SP - 1 EP - 14 PB - Springer Fachmedien CY - Wiesbaden ER - TY - CHAP A1 - Lehmann, Christian A1 - Berger, Ulrich A1 - Städter, Jost Philipp A1 - Mariani, G. A1 - Armento, A. A1 - Cigarini, M. T1 - Inline-Qualitätsprüfung für Montageprozesse mittels impedanzgeregeltem Leichtbauroboter T2 - Automation 2015, Baden-Baden, 11-12 Juni 2015 Y1 - 2015 SN - 978-3-18-092258-4 SP - 1035 EP - 1044 PB - VDI-Verlag CY - Düsseldorf ER - TY - CHAP A1 - Lehmann, Christian A1 - Städter, Jost Philipp A1 - Berger, Ulrich A1 - Keller, Sebastian A1 - Gnorski, Harry T1 - Semi-automated Handling of Manhole Covers for Tank Wagon Processing Using Industrial Robots T2 - IEEE/RSJ International Conference on Intelligent Robots and Systems, (IROS 2013), Tokyo, Japan, 3 - 7 November 2013 Y1 - 2013 UR - http://lasa.epfl.ch/workshop_ratis/iros_ratis_btu_lehmann_final.pdf ER - TY - CHAP A1 - Lehmann, Christian A1 - Wächter, Kornelius A1 - Städter, Jost Philipp T1 - A variant-flexible assembly cell for hydraulic valve sections using a sensitive lightweight robot T2 - Robotics in the era of digitalisation, 47th International Symposium on Robotics, June 21-22, 2016, Messe München, Entrance East, Munich, Germany Y1 - 2016 SN - 978-3-8007-4231-8 SP - 645 EP - 651 PB - VDE-Verlag CY - Berlin [u.a.] ER - TY - CHAP A1 - Minhas, Sarfraz Ul-Haque A1 - Lehmann, Christian A1 - Städter, Jost Philipp A1 - Berger, Ulrich T1 - Reconfigurable Strategies for Manufacturing Setups to confront Mass Customization Challanges N2 - The manufacturing industry is distinguished by regionalization and individualization of products accompaniedby varying customer demands, faster time to market, short innovation cycles and product life cycles. Theintroduction of new materials, new processes as well as struggle to achieve economic and efficient use ofresources has raised complexities to achieve quick and optimal configuration in manufacturing systems. Toresolve the complexities, the reconfiguration at different levels in the manufacturing system is presented byusing three distinct examples. The first example refers to reconfigurable joining cell design for versatile joiningof automotive subassemblies. Second example refers to strategy for quick reconfiguration of robots for precisemachining applications. The third example elaborates fast calibration of monitoring system in joiningprocesses to enable fast reconfiguration of sensors in commissioning as well as in the maintenance. KW - Reconfigurable manufacturing cell KW - plug and produce KW - one-of-a-kind Y1 - 2011 ER - TY - GEN A1 - Städter, Jost Philipp A1 - Lehmann, Christian A1 - Halbauer, Marcel A1 - Berger, Ulrich A1 - Gnorski, Harry A1 - Schulze, T. T1 - Automatisierte robotergestützte Gefahrgutverladung im explosionsgeschützten Outdoorbereich T2 - Technische Sicherheit Y1 - 2013 SN - 2191-0073 SP - 40 EP - 46 ER -