07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/8
Browse
4 results
Search Results
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 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.