@inproceedings{57180,
  author       = {{Lenz, Cederic and Bause, Maximilian and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{2024 International Conference on Advanced Robotics and Mechatronics (ICARM)}},
  publisher    = {{IEEE}},
  title        = {{{Boosting Low Data PINN Robustness with Transfer Learning*}}},
  doi          = {{10.1109/icarm62033.2024.10715896}},
  year         = {{2024}},
}

@inproceedings{57181,
  author       = {{Lenz, Cederic and Bause, Maximilian and Reiling, Fabian and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{2024 IEEE International Conference on Advanced Intelligent Mechatronics (AIM)}},
  publisher    = {{IEEE}},
  title        = {{{Contextual Anomaly Detection in Hot Forming Production Line using PINN Architecture}}},
  doi          = {{10.1109/aim55361.2024.10637234}},
  year         = {{2024}},
}

@phdthesis{58450,
  abstract     = {{Die vorliegende Arbeit befasst sich mit der modellprädiktiven Planung zeitoptimierter Trajektorien für mehrachsige kinematisch redundante Mechanismen. Es werden zunächst grundlegende Begriffe erläutert, bevor der Stand der Wissenschaft und Technik hinsichtlich der Trajektorienplanung von kinematisch redundanten und nicht-redundanten Mechanismen sowie der Ausführung von Optimierungen auf Industriesteuerungen vorgestellt wird. Im Anschluss wird die modellprädiktive Planung erläutert. Diese nutzt die Mehrdeutigkeit bei der Ermittlung der Gelenkpositionen kinematisch redundanter Mechanismen, um die Verfahrzeit zwischen Sollpositionen im Rahmen von Punkt-zu-Punkt-Bewegungen zu minimieren. Anhand eines kinematisch redundanten hybridkinematischen Mechanismus erfolgt zunächst eine simulative Validierung des Ansatzes. Bezogen auf die immer flexibler werdenden Fertigungen im Kontext Losgröße-1 sind jedoch echtzeitfähige selbstoptimierende Steuerungen erforderlich, die sich zur Laufzeit auf wechselnde Aufgaben einstellen und mit weiteren Systemen interagieren. Aus diesem Grund liegt der Fokus auf der echtzeitfähigen Ausführung des Ansatzes auf einer Industriesteuerung, ein entscheidender Punkt, um die erforderliche Flexibilität und industrielle Einsetzbarkeit zu erreichen und gleichzeitig ein signifikanter Unterschied zum Stand der Technik. Hierzu erfolgt die Umsetzung auf das reale System und der Nachweis der echtzeitfähigen Ausführung mit Optimierungszeiten kleiner einer Millisekunde.}},
  author       = {{Rüting, Arne Thorsten}},
  title        = {{{Echtzeitfähige modellprädiktive Planung zeitoptimierter Trajektorien für kinematisch redundante Mechanismen auf industrieller Hardware}}},
  doi          = {{10.17619/UNIPB/1-2112}},
  year         = {{2024}},
}

@article{57893,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>Control engineering applications usually require a model that accurately represents the dynamics of the system. In addition to classical physical modeling, powerful data‐driven approaches are gaining popularity. However, the resulting models may not be ideal for control design due to their black‐box structure, which inherently limits interpretability. Formulating the system dynamics in port‐Hamiltonian form is highly beneficial, as its valuable property of passivity enables the straightforward design of globally stable controllers while ensuring physical interpretability. In a recently published article, we presented a method for data‐driven inference of port‐Hamiltonian models for complex mechatronic systems, requiring only fundamental physical prior knowledge. The resulting models accurately represent the nonlinear dynamics of the considered systems and are physically interpretable. In this contribution, we advance our previous work by including two key elements. Firstly, we demonstrate the application of the above described data‐driven PCHD models for controller design. Preserving the port‐Hamiltonian form in the closed loop not only guarantees global stability and robustness but also ensures desired speed and damping characteristics. Since control systems based on output measurements, which are continuously measured during operation due to the feedback structure, we secondly aim to use this data. Thus, we augment the existing modeling strategy with an intelligent adaptation approach to address uncertainties and (un)predictable system changes in mechatronic systems throughout their lifecycle, such as the installation of new components, wear, or temperature fluctuations during operation. Our proposed algorithm for recursively calculated data‐driven port‐Hamiltonian models utilizes a least‐squares approach with extensions such as automatically adjusting the forgetting factor and controlling the covariance matrix trace. We demonstrate the results through model‐based application on an academic example and experimental validation on a test bench.</jats:p>}},
  author       = {{Junker, Annika and Timmermann, Julia and Trächtler, Ansgar}},
  issn         = {{1617-7061}},
  journal      = {{PAMM}},
  number       = {{1}},
  publisher    = {{Wiley}},
  title        = {{{Adaptive Data‐Driven Models in Port‐Hamiltonian Form for Control Design}}},
  doi          = {{10.1002/pamm.202400154}},
  volume       = {{25}},
  year         = {{2024}},
}

@article{59051,
  abstract     = {{Model‐based state observers require high‐quality models to deliver accurate state estimates. However, due to time or cost shortage, modeling simplifications or numerical issues, models often have severe inaccuracies that may lead to insufficient and deficient control. Instead of attempting to iteratively model these deviations, we address the challenge by the concept of joint estimation. Thus, we assume a linear combination of suitable functions to approximate the inaccuracies. The parameters of the linear combination are supposed to be time invariant and augment the model's state. Subsequently, the parameters can be identified simultaneously to the states within the observer. Referring to the principle of Occam's razor, the parameters are claimed to be sparse. Our former work shows that estimating states and model inaccuracies simultaneously by a sparsity promoting unscented Kalman filter yields not only high accuracy but also provides interpretable representations of underlying inaccuracies. Based on this work, our contribution is twofold: First, we apply our approach finally on a real‐world test bench, namely a golf robot. Within the experimental setting, we investigate closed loop behavior as well as how suitable functions need to be chosen to approximate the inaccuracies in a physically interpretable way. Results do not only provide high state estimation accuracy but also meaningful insights into the system's inaccuracies. Second, we discuss and establish a method to automatically adapt and update the model based on collected data of the linear combination during operation. Examining past parameter estimates by principal component analysis, a moving window is utilized to extract the most dominant functions. These are kept characterizing the model inaccuracies, while nondominant functions are automatically neglected and refilled with novel function candidates. After analysis and rebuilding, this updated function set is subsequently fed back into the joint estimation loop and deployed for further estimation. Hence, we give a holistic paradigm of how to analyze and combat model inaccuracies while ensuring high state estimation accuracy. Within this setting, we once more investigate closed loop behavior and yield promising results. In conclusion, we show that the proposed observer provides a helpful tool to guarantee high estimation accuracy for models with severe inaccuracies or for situations with occurring deviations during operation, for example, due to mechanical wear or temperature changes.</jats:p>}},
  author       = {{Götte, Ricarda-Samantha and Timmermann, Julia}},
  issn         = {{1617-7061}},
  journal      = {{PAMM}},
  number       = {{1}},
  publisher    = {{Wiley}},
  title        = {{{Online Learning With Joint State and Model Estimation}}},
  doi          = {{10.1002/pamm.202400080}},
  volume       = {{25}},
  year         = {{2024}},
}

@inproceedings{48577,
  author       = {{Henkenjohann, Mark and Nolte, Udo and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{2023 International Conference on Unmanned Aircraft Systems (ICUAS)}},
  publisher    = {{IEEE}},
  title        = {{{Novel Cascaded Incremental Nonlinear Dynamic Inversion Controller Approach for a Tiltrotor VTOL}}},
  doi          = {{10.1109/icuas57906.2023.10156317}},
  year         = {{2023}},
}

@inproceedings{44316,
  author       = {{Rozo Vasquez, Julian and Arian, Bahman and Kersting, Lukas and Walther, Frank and Homberg, Werner and Trächtler, Ansgar}},
  location     = {{Krakau}},
  title        = {{{Softsensor model of phase transformation during flow forming of metastable austenitic steel AISI 304L}}},
  year         = {{2023}},
}

@article{48781,
  abstract     = {{In a punch-bending machine, wire products are manufactured for a wide range of industrial sectors, such as the electronics industry. The raw material for this process is flat wire made of high-strength steel. During the manufacturing process of the flat wire, residual stresses and plastic deformations are induced into the wire. These residual stresses and deformations fluctuate over the length of the semi-finished product and have a negative effect on the final product quality. Straightening machines are used to reduce this influence to a minimum. So far, the adjustment of a straightening machine has been performed manually, which is a lengthy and complex task even for an experienced worker. This inevitably leads to the use of inefficient straightening strategies and causes high rejection rates in the entire production process. Due to a lack of sensor information from the straightening operation, application of modern feedback control methods has not been practicable. This paper presents a novel design for a straightening machine with an integrated, precise straightening force measurement. By simultaneously monitoring the position of the straightening rollers, state variables of the straightening operation can be derived. Additionally, a tension control for feeding the flat wire is introduced. This is implemented to mitigate the disturbing effects caused by irregularities in the wire-feeding process. In the results of this article, the high precision of the developed force measurement design and its possible applications are shown.}},
  author       = {{Bathelt, Lukas and Scurk, Maximilian and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar}},
  issn         = {{1424-8220}},
  journal      = {{Sensors}},
  number       = {{22}},
  title        = {{{Novel Straightening-Machine Design with Integrated Force Measurement for Straightening of High-Strength Flat Wire}}},
  doi          = {{10.3390/s23229091}},
  volume       = {{23}},
  year         = {{2023}},
}

@inproceedings{48570,
  author       = {{Lenz, Cederic and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{2023 IEEE 21st International Conference on Industrial Informatics (INDIN)}},
  publisher    = {{IEEE}},
  title        = {{{A Methodical Approach to Hybrid Modelling for Contextual Anomaly Detection on Time-Series Data}}},
  doi          = {{10.1109/indin51400.2023.10218108}},
  year         = {{2023}},
}

@inproceedings{48572,
  abstract     = {{<jats:p>Abstract. To increase the sustainability of forming processes such as punch bending, homogenization of the processed semi-finished product is an essential step in the manufacturing process. High-strength wire materials are usually available as strip material before being further processed in a forming process. For storage and transport, the material is coiled onto coils and transported to the customer. During the coiling process, residual stresses and plastic deformation are introduced into the wire. Thus, the final product quality is also influenced by the geometry of the coil. Straightening machines are used in production lines to compensate for these. Once a straightening machine has been set up, the settings for the roll positions are usually not changed. As a result, there is no reaction to material fluctuations, which means that the components to be produced do not meet the dimensional accuracy requirements. This leads to an increase in the rejection rate in manufacturing processes. To reduce the rejection rate, it is necessary to enable dynamic and flexible infeed of the straightening rollers. In this context, an innovative control concept with disturbance compensation was developed for the straightening process. The disturbance compensation uses a disturbance model that predicts the change in bending curvature over the coil radius. With this prediction, the straightening machine can be adjusted specifically. The roller positions are adjusted by a subordinate position control. The additional feedback from measured geometric product properties from the following punching-bending process enables the straightening machine to be adjusted even in the case of unforeseen fluctuations in the material properties. In this way, it is possible to react to any material fluctuations as required. This novel, demand-oriented adjustment of the straightening machine is expected to result in a high increase in the efficiency of the production process and a reduction of the rejection rate. </jats:p>}},
  author       = {{Bathelt, Lukas and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{Materials Research Proceedings}},
  issn         = {{2474-395X}},
  publisher    = {{Materials Research Forum LLC}},
  title        = {{{Innovative self-learning disturbance compensation for straightening processes}}},
  doi          = {{10.21741/9781644902479-216}},
  year         = {{2023}},
}

@inproceedings{48001,
  author       = {{Bathelt, Lukas and Djakow, Eugen and Dahms, Frederik and Henke, Christian and Trächtler, Ansgar and Homberg, Werner}},
  booktitle    = {{Ilmenauer Federntag 2023: Neueste Erkenntnisse zu Funktion, Berechnung, Prüfung und Gestaltung von Federn und Werkstoffen}},
  isbn         = {{978-3-948595-09-8}},
  location     = {{Ilmenau}},
  publisher    = {{ISLE Steuerungstechnik und Leistungselektronik}},
  title        = {{{Neuartiger Ansatz zum Richten von zwei- und dreidimensionalen Fehlern an einem Federdraht}}},
  year         = {{2023}},
}

@inproceedings{48571,
  author       = {{Koppert, Steven and Bause, Maximilian and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{2023 IEEE 21st International Conference on Industrial Informatics (INDIN)}},
  publisher    = {{IEEE}},
  title        = {{{Learning the Automated Setup of Profile Wrapping Lines for New Products from Few Past Setups}}},
  doi          = {{10.1109/indin51400.2023.10217972}},
  year         = {{2023}},
}

@inproceedings{49560,
  author       = {{Stieren, Stephan and Wichtrup, Moritz and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{NEIS - Conference on Sustainable Energy Supply and Energy Storage Systems}},
  location     = {{Hamburg}},
  title        = {{{Concept for a cloud-based holistic energy management of domestic appliances to stabilize the energy supply and the power grid}}},
  year         = {{2023}},
}

@inproceedings{44314,
  abstract     = {{<jats:p>Abstract. Workpiece property-control permits the application-oriented and time-efficient production of components. In reverse flow forming, for example, a control of the microstructure profile is not yet part of the state of the art, in contrast to the geometry control. This is, due to several reasons, particularly challenging when forming seamless tubes made of metastable austenitic stainless AISI 304L steel. Inducing mechanical and/or thermal energy can cause a phase transformation from austenite to martensite within this steel. The resulting α’-martensite has different mechanical and micromagnetic properties, which can be advantageous depending on the application. For purposes of local property control, the resulting α’-martensite content should be measured and controlled online during the forming process. This paper presents results from the usage of a custom developed cryo-system and different application strategies to use liquid nitrogen as a coolant for local enhancement of the forming-temperature depending α’-martensite content. </jats:p>}},
  author       = {{Arian, Bahman and Homberg, Werner and Kersting, Lukas and Trächtler, Ansgar and Rozo Vasquez, Julian and Walther, Frank}},
  booktitle    = {{Materials Research Proceedings}},
  issn         = {{2474-395X}},
  publisher    = {{Materials Research Forum LLC}},
  title        = {{{Cryogenic reverse flow forming of AISI 304L}}},
  doi          = {{10.21741/9781644902479-219}},
  year         = {{2023}},
}

@article{48075,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>The constantly increasing challenges of production technology for the economic and resource-saving production of metallic workpieces require, among other things, the optimisation of existing processes. Forming technology, which is confronted with new challenges regarding the quality of the workpieces, must also organise the individual processes more efficiently and at the same time more reliably in order to be able to guarantee good workpiece quality and at the same time to be able to produce economically. One way to meet these challenges is to carry out the forming processes in closed-loop control systems using softsensors. Despite the many potential applications of softsensors in the field of forming technology, there is still no definition of the term softsensor. This publication therefore proposes a definition of the softsensor based on the definition of a sensor and the distinction from the observer, which on the one hand is intended to stimulate scientific discourse and on the other hand is also intended to form the basis for further scientific work. Based on this definition, a wide variety of highly topical application examples of various softsensors in the field of forming technology are given.</jats:p>}},
  author       = {{Homberg, Werner and Arian, Bahman and Arne, Viktor and Borgert, Thomas and Brosius, Alexander and Groche, Peter and Hartmann, Christoph and Kersting, Lukas and Laue, Robert and Martschin, Juri and Meurer, Thomas and Spies, Daniel and Tekkaya, A. Erman and Trächtler, Ansgar and Volk, Wolfram and Wendler, Frank and Wrobel, Malte}},
  issn         = {{0944-6524}},
  journal      = {{Production Engineering}},
  keywords     = {{Industrial and Manufacturing Engineering, Mechanical Engineering}},
  publisher    = {{Springer Science and Business Media LLC}},
  title        = {{{Softsensors: key component of property control in forming technology}}},
  doi          = {{10.1007/s11740-023-01227-1}},
  year         = {{2023}},
}

@phdthesis{42344,
  author       = {{Rüddenklau, Nico}},
  title        = {{{Hardware-in-the-Loop-Simulation von HD-Scheinwerfer-Steuergeräten zur Entwicklung von Lichtfunktionen in virtuellen Nachtfahrten}}},
  year         = {{2023}},
}

@phdthesis{42345,
  author       = {{Biemelt, Patrick}},
  title        = {{{Entwurf und Analyse modellprädiktiver Regelungsansätze zur Steigerung des Immersionsempfindens in interaktiven Fahrsimulationen}}},
  year         = {{2023}},
}

@inproceedings{44390,
  abstract     = {{The development of autonomous vehicles and their introduction in urban traffic offer many opportunities for traffic improvements. In this paper, an approach for a future traffic control system for mixed autonomy traffic environments is presented. Furthermore, a simulation framework based on the city of Paderborn is introduced to enable the development and examination of such a system. This encompasses multiple elements including the road network itself, traffic lights, sensors as well as methods to analyse the topology of the network. Furthermore, a procedure for traffic demand generation and routing is presented based on statistical data of the city and traffic data obtained by measurements. The resulting model can receive and apply the generated control inputs and in turn generates simulated sensor data for the control system based on the current system state.}},
  author       = {{Link, Christopher and Malena, Kevin and Gausemeier, Sandra and Trächtler, Ansgar}},
  booktitle    = {{Proceedings of the 9th International Conference on Vehicle Technology and Intelligent Transport Systems}},
  isbn         = {{978-989-758-652-1}},
  keywords     = {{Traffic Simulation, Traffic Control, Car2X, Mixed Autonomy, Autonomous Vehicles, SUMO, Sensor Simulation, Traffic Demand Generation, Routing, Traffic Lights, Graph Analysis, Traffic Observer}},
  location     = {{Prague, Czech Republic}},
  publisher    = {{SCITEPRESS - Science and Technology Publications}},
  title        = {{{Simulation Environment for Traffic Control Systems Targeting Mixed Autonomy Traffic Scenarios}}},
  doi          = {{10.5220/0011987600003479}},
  year         = {{2023}},
}

@article{44312,
  abstract     = {{<jats:title>Zusammenfassung</jats:title>
               <jats:p>Aufgrund aktueller Transformationsprozesse kommt der automatisierten und ressourceneffizienten Fertigung hochfester Leichtbauteile eine steigende Bedeutung zu, beispielsweise im Flugzeug- und Fahrzeugbau. Für kleine Losgrößen bietet sich hier insbesondere das Fertigungsverfahren des Drückwalzens an. Der konventionelle, industriell genutzte Drückwalzprozess stößt allerdings aufgrund der Prozesskomplexität hinsichtlich der Reproduzierbarkeit an seine Grenzen. Dies wird in der Praxis teilweise durch personengebundenes Erfahrungswissen kompensiert. Auch ist es nicht möglich, Bauteileigenschaften definiert einzustellen. Aus diesem Grund bietet der Einsatz einer neuartigen Eigenschaftsregelung Chancen zur Weiterentwicklung des Fertigungsprozesses und die Möglichkeit zur Prozessautomatisierung. Hier werden die Werkzeugbahnen abhängig einer Online-Eigenschaftsmessung über eine zusätzliche Reglerkaskade manipuliert. Die Entwicklung einer solchen Eigenschaftsregelung erfordert den Einsatz geeigneter, modellbasierter Entwurfsmethoden. In diesem Beitrag wird daher ein regelungstechnisches Systemmodell für das Drückwalzen metastabiler austenitischer Edelstähle vorgestellt. Das Simulationsmodell weist aufgrund seiner Echtzeitfähigkeit neben dem Einsatz als reines Entwurfsmodell weitere Nutzungsmöglichkeiten z.B. in Beobachtern auf und grenzt sich somit von domänenspezifischen Simulationstools wie der FEM ab.</jats:p>}},
  author       = {{Kersting, Lukas and Arian, Bahman and Rozo Vasquez, Julian and Trächtler, Ansgar and Homberg, Werner and Walther, Frank}},
  issn         = {{0178-2312}},
  journal      = {{at - Automatisierungstechnik}},
  keywords     = {{Electrical and Electronic Engineering, Computer Science Applications, Control and Systems Engineering}},
  number       = {{1}},
  pages        = {{68--81}},
  publisher    = {{Walter de Gruyter GmbH}},
  title        = {{{Echtzeitfähige Modellierung eines innovativen Drückwalzprozesses für die eigenschaftsgeregelte Bauteilfertigung}}},
  doi          = {{10.1515/auto-2022-0106}},
  volume       = {{71}},
  year         = {{2023}},
}

@inproceedings{44315,
  abstract     = {{<jats:p>Abstract. Climate change, rare resources and industrial transformation processes lead to a rising demand of multi-complex lightweight forming parts, especially in aerospace and automotive sectors. In these industries, flow forming is often used to produce cylindrical forming parts by reducing the wall thickness of tubular semifinished parts, e.g. for the production of hydraulic cylinders or gear shafts. The complexity and functionality of flow forming workpieces could be significantly increased by locally graded microstructure and geometry structures. This enables customized complex hardness distributions at wear surfaces or magnetic QR codes for a unique, tamper-proof product identification. The production of those complex, 2D (axial and angular) graded forming parts currently depicts a great challenge for the process and requires new solutions and strategies. Hence, this paper proposes a novel control strategy that includes online measurements from an absolute encoder to determine the angular workpiece position. Workpieces of AISI 304L stainless steel with 2D-graded structures are successfully manufactured using this new strategy and analyzed regarding the possible accuracy and resolution of the gradation. At this point, a dependency of the gradations on the sensor and actuator dynamics, accuracy and geometry could be noted. It is further evaluated how the control strategy could be extended by an observer-based closed-loop property control approach to enhance the accuracy of the suggested strategy. </jats:p>}},
  author       = {{Kersting, Lukas and Arian, Bahman and Rozo Vasquez, Julian and Trächtler, Ansgar and Homberg, Werner and Walther, Frank}},
  booktitle    = {{Materials Research Proceedings}},
  issn         = {{2474-395X}},
  publisher    = {{Materials Research Forum LLC}},
  title        = {{{Control strategy for angular gradations by means of the flow forming process}}},
  doi          = {{10.21741/9781644902479-220}},
  year         = {{2023}},
}