07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/8
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Item Open Access Influence of exoskeleton use on Cardiac Index(2022) Schalk, Marco; Schalk, Ines; Bauernhansl, Thomas; Siegert, Jörg; Schneider, UrsThis study aims to assess the whole-body physiological effects of wearing an exoskeleton during a one-hour standardized work task, utilizing the Cardiac Index (CI) as the target parameter. N = 42 young and healthy subjects with welding experience took part in the study. The standardized and abstracted one-hour workflow consists of simulated welding and grinding in constrained body positions and was completed twice by each subject, with and without an exoskeleton, in a randomized order. The CI was measured by Impedance Cardiography (ICG), an approved medical method. The difference between the averaged baseline measurement and the averaged last 10 min was computed for the conditions with and without an exoskeleton for each subject to result in ∆CIwithout exo and ∆CIwith exo. A significant difference between the conditions with and without an exoskeleton was found, with the reduction in CI when wearing an exoskeleton amounting to 10.51%. This result corresponds to that of previous studies that analyzed whole-body physiological load by means of spiroergometry. These results suggest a strong positive influence of exoskeletons on CI and, therefore, physiological load. At the same time, they also support the hypothesis that ICG is a suitable measurement instrument to assess these effects.Item Open Access An exploratory analysis of the current status and potential of service-oriented and data-driven business models within the sheet metal working sector : insights from interview-based research in small and medium-sized enterprises(2024) Wirth, Jonas; Schneider, Mirko; Hanselmann, Leon; Fink, Kira; Nebauer, Stephan; Bauernhansl, ThomasResponding to changing value creation processes in the sheet metal working sector, where the complexity and interchangeability of products challenge traditional differentiation strategies, this exploratory analysis examines the integration of service-oriented and data-driven business models as new paths to ensure competitiveness, especially for small and medium-sized enterprises (SMEs). This study aims to capture the current state and challenges associated with the implementation of these business models in this sector. This research was conducted through semi-structured interviews with SMEs in the industry. The findings indicate that service-oriented and data-driven business models are not yet widely adopted and that manufacturing companies require support in their implementation. Fields of action were identified for the industry. These are “Creating awareness and understanding”, “Recognizing added value”, “Increasing company maturity”, and “Understanding the change process”. Cooperation between science and industry is essential in tackling these fields of action to ensure the successful integration of such business models in manufacturing companies. This paper identifies challenges in the fields of action that companies must address through a structured approach, promoting awareness, recognizing value, improving organizational maturity, and understanding the change process to successfully implement service-oriented and data-driven business models.Item Open Access Decarbonization drivers and their impact on business models in the energy-intensive manufacturing industry (EIMI)(2024) Mais, Franziska; Bauernhansl, ThomasEIMIs face the challenge of adapting to the Paris Agreement and the European Green Deal to achieve carbon neutrality. Driven by consumer interest in low-carbon products, regulatory requirements, and investor priorities, companies are pressured to integrate sustainability beyond short-term financial gains. The growing awareness of the environmental impact of business models (BM) has fueled the development of Sustainable Business Models (SBMs). Although the importance of decarbonization of EIMIs has increased, there is a lack of industry-specific research examining the combination of decarbonization and business models, as well as their interrelationships and correlations. This study addresses the discussion on the role of SBMs in decarbonization, improving the understanding of how these drivers can be integrated to enable new BMs for EIMIs. Based on a structured literature review and semi-structured interviews within the EIMIs, the study identifies BM components influenced by these drivers requiring sustainable business model innovation (SBMI). Results show that decarbonization drivers significantly impact all BM components. Experts emphasize the importance of collaborative approaches and cooperation throughout the value chain. This research highlights the need for systematic analysis to understand how companies can manage decarbonization drivers effectively and suggests exploring potential SBM design options.Item Open Access Disruptive factors in product portfolio management : an exploratory study in B2B manufacturing for sustainable transition(2024) Gramberg, Till; Bauernhansl, Thomas; Eggert, AndreasBusiness-to-business (B2B) manufacturing companies are increasingly confronted with transformative trends such as sustainability, digitalization, and servitization. These trends are changing how product portfolios are developed, and how value contributions are assessed, and therefore have disruptive potential. Dealing with these disruptive factors in Product Portfolio Management (PPM) is a largely unexplored topic. This study presents an empirical-qualitative exploration that contributes significantly to the field. The aim is to clarify the extent to which disruptive factors influence the evaluation and shaping of the product portfolio in B2B manufacturing companies. The Gioia method was used to evaluate 21 semi-structured interviews with experts from leading B2B manufacturing companies. Eight overarching challenges in PPM resulting from disruptive factors were identified. Based on the eight overarching challenges and their associated causal relationships, two aggregated dimensions of action were derived: (1) increasing speed and flexibility by using generative artificial intelligence (AI) in a defined PPM process and (2) adjusting the product portfolio evaluation to consider various strategic drivers. These two dimensions of action call for future research to overcome the disruptive factors in PPM.Item Open Access Model-based biomechanical exoskeleton concept optimization for a representative lifting task in logistics(2022) Schiebl, Jonas; Tröster, Mark; Idoudi, Wiem; Gneiting, Elena; Spies, Leon; Maufroy, Christophe; Schneider, Urs; Bauernhansl, ThomasOccupational exoskeletons are a promising solution to prevent work-related musculoskeletal disorders (WMSDs). However, there are no established systems that support heavy lifting to shoulder height. Thus, this work presents a model-based analysis of heavy lifting activities and subsequent exoskeleton concept optimization. Six motion sequences were captured in the laboratory for three subjects and analyzed in multibody simulations with respect to muscle activities (MAs) and joint forces (JFs). The most strenuous sequence was selected and utilized in further simulations of a human model connected to 32 exoskeleton concept variants. Six simulated concepts were compared concerning occurring JFs and MAs as well as interaction loads in the exoskeleton arm interfaces. Symmetric uplifting of a 21 kg box from hip to shoulder height was identified as the most strenuous motion sequence with highly loaded arms, shoulders, and back. Six concept variants reduced mean JFs (spine: >70%, glenohumeral joint: >69%) and MAs (back: >63%, shoulder: >59% in five concepts). Parasitic loads in the arm bracing varied strongly among variants. An exoskeleton design was identified that effectively supports heavy lifting, combining high musculoskeletal relief and low parasitic loads. The applied workflow can help developers in the optimization of exoskeletons.Item Open Access Biomechanical analysis of stoop and free-style squat lifting and lowering with a generic back-support exoskeleton model(2022) Tröster, Mark; Budde, Sarah; Maufroy, Christophe; Andersen, Michael Skipper; Rasmussen, John; Schneider, Urs; Bauernhansl, ThomasMusculoskeletal disorders (MSDs) induced by industrial manual handling tasks are a major issue for workers and companies. As flexible ergonomic solutions, occupational exoskeletons can decrease critically high body stress in situations of awkward postures and motions. Biomechanical models with detailed anthropometrics and motions help us to acquire a comprehension of person- and application-specifics by considering the intended and unintended effects, which is crucial for effective implementation. In the present model-based analysis, a generic back-support exoskeleton model was introduced and applied to the motion data of one male subject performing symmetric and asymmetric dynamic manual handling tasks. Different support modes were implemented with this model, including support profiles typical of passive and active systems and an unconstrained optimal support mode used for reference to compare and quantify their biomechanical effects. The conducted simulations indicate that there is a high potential to decrease the peak compression forces in L4/L5 during the investigated heavy loaded tasks for all motion sequences and exoskeleton support modes (mean reduction of 13.3% without the optimal support mode). In particular, asymmetric motions (mean reduction of 14.7%) can be relieved more than symmetric ones (mean reduction of 11.9%) by the exoskeleton support modes without the optimal assistance. The analysis of metabolic energy consumption indicates a high dependency on lifting techniques for the effectiveness of the exoskeleton support. While the exoskeleton support substantially reduces the metabolic cost for the free-squat motions, a slightly higher energy consumption was found for the symmetric stoop motion technique with the active and optimal support mode.Item Open Access Investigation of possible effects of wearing exoskeletons during welding on heart rate(2022) Schalk, Marco; Schalk, Ines; Bauernhansl, Thomas; Siegert, Jörg; Schneider, UrsThis study aims to investigate the possible effects of wearing exoskeletons during welding on heart rate. Additionally, the validity of a measuring instrument for determining acute heart rate is to be assessed. N = 15 young healthy subjects with welding experience took part in the study. The study design defines a one-hour workflow that abstracts welding and grinding tasks. The sequence is based on the internationally recognized standard DIN EN ISO 9606-1 and reproduces authentic work sequences in constrained body positions. Each subject completed the workflow once with and once without an exoskeleton. Recorded measures were the heart rates measured by a wrist-worn smartwatch and by Impedance Cardiography (ICG). The average heart rate shows no statistically significant differences in the measurement series with and without exoskeletons. The temporal variation of the heart rate shows a statistically significant influence of wearing exoskeletons and provides a moderate to strong effect, corresponding to a Cohens d of d = 0.78. Only 28.57% of all data series obtained with a smartwatch were equivalent to ICG-data after analysis with t-test, Pearson’s correlation, and orthogonal regression. Using averaged heart rates to assess exoskeleton effects is not a suitable measure. A trend analysis using linear regression shows moderate to strong statistically significant effects in the time course of heart rates and provides an approach to evaluate exoskeleton-induced effects.Item Open Access Integrating ionic electroactive polymer actuators and sensors into adaptive building skins: potentials and limitations(2020) Neuhaus, Raphael; Zahiri, Nima; Petrs, Jan; Tahouni, Yasaman; Siegert, Jörg; Kolaric, Ivica; Dahy, Hanaa; Bauernhansl, ThomasBuilding envelopes separate the confined interior world engineered for human comfort and indoor activity from the exterior world with its uncontainable climatic forces and man-made immission. In the future, active, sustainable and lightweight building skins are needed to serve as an adaptive interface to govern the building-physical interactions between these two worlds. This article provides conceptual and experimental results regarding the integration of ionic electroactive polymer sensors and actuators into fabric membranes. The ultimate goal is to use this technology for adaptive membrane building skins. These devices have attracted high interest from industry and academia due to their small actuation voltages, relatively large actuation and sensing responses and their flexible and soft mechanical characteristics. However, their complex manufacturing process, sophisticated material compositions and their environmental sensitivity have limited the application range until now. The article describes the potentials and limitations of employing such devices for two different adaptive building functionalities: first, as a means of ventilation control and humidity regulation by embedding small actuated apertures into a fabric membrane, and second, as flexible, energy- and cost-efficient distributed sensors for external load monitoring of such structures. The article focusses on designing, building and testing of two experimental membrane demonstrators with integrated polymer actuators and sensors. It addresses the challenges encountered and draws conclusions for potential future optimization at the device and system level.Item Open Access Design options for sustainable and open business models : a taxonomy-based analysis(2024) Mais, Franziska; Bauernhansl, ThomasThe imperative for decarbonization forces businesses to transform their business models (BMs) and to adopt Sustainable Business Models which focus on creating value sustainably. In the context of Sustainable Business Model Innovation, maintaining close relationships within ecosystems is crucial to ensure a sustainable transformation while preserving competitiveness. As corporate boundaries become more transparent, the importance of external resources increases, leading to a shift from closed to open business models (OBM). In OBMs, stakeholders, including customers, actively co-create innovation and value creation. Our research investigates how integrating these approaches can shape BMs that effectively address decarbonization drivers and tackle the required business model innovation. We conducted a structured literature review to develop a taxonomy that outlines 64 design options across nine dimensions for sustainable, open BMs. In conclusion, this study provides sustainable and open design options, classified into detailed taxonomies. The practical applicability of this taxonomy was demonstrated through a use case classification, providing a foundation for companies and further research into designing and implementing these BMs in the context of decarbonization.