Universität Stuttgart

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Institute: search.filters.UBSInstitut.Fraunhofer Institut für Produktionstechnik und Automatisierung (IPA)Institute: search.filters.UBSInstitut.Institut für Industrielle Fertigung und FabrikbetriebSubject: search.filters.subject.621.3Start date: 2017

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    Position sensor and control system for micro hydraulic drives in surgical instruments
    (Stuttgart : Fraunhofer Verlag, 2019) Comella, Laura; Bauernhansl, Thomas (Univ.-Prof. Dr.-Ing.)
    This work is focused on the research and development of a sensor that permits the control of the movement of a hydraulically driven laparoscopic instrument tip and opens the way towards a new interpretation of surgical instruments. In the new vision the instrument is able to execute automatically preprogrammed tasks, without the constant involvement of the surgeon in the instrument control. After an analysis on the state of the art for laparoscopic instruments and a revision of the relevant literature on sensors for displacement measurement, the coaxial cylindrical capacitive method was identified as the most suitable solution for the application analyzed. This sensor configuration can be integrated directly into the hydraulic cylinder without the need of additional parts. The feasibility of the coaxial cylindrical capacitive sensor is theoretically analyzed, validated with FEA simulation and then characterized experimentally. Relevant is the fact that the tests are run with two different hydraulic cylinders, a mini hydraulic and a micro hydraulic cylinder, to demonstrate the scalability of the sensor and its adaptability to instruments of different size. The experimental results match the simulations and confirm the sensor´s behavior also on experimental level. The sensor is than integrated in a closed loop system to test its suitability for controlling the position of the instrument tip in a scenario as close as possible to the real one. For this reason, a hydraulic drive, which permits the movement of the instrument tip, is designed. The full hydraulic drive system is modeled and this model is used to design a feedback control. The designed controller is initially proven through simulation. Afterwards it is tested with experiments proving the correspondence between simulated and real world behavior of the system.
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    ItemOpen Access
    User-friendly, requirement-based assistance for production workforce using an asset administration shell design
    (2020) Al Assadi, Anwar; Fries, Christian; Fechter, Manuel; Maschler, Benjamin; Ewert, Daniel; Schnauffer, Hans-Georg; Zürn, Michael; Reichenbach, Matthias
    Future production methods like cyber physical production systems (CPPS), flexibly linked assembly structures and the matrix production are characterized by highly flexible and reconfigurable cyber physical work cells. This leads to frequent job changes and shifting work environments. The resulting complexity within production increases the risk of process failures and therefore requires longer job qualification times for workers, challenging the overall efficiency of production. During operation, cyber physical work cells generate data, which are specific to the individual process and worker. Based on the asset administration shell for Industry 4.0, this paper develops an administration shell for the production workforce, which contains personal data (e.g. qualification level, language skills, machine access, preferred display and interaction settings). Using worker and process specific data as well as personal data, allows supporting, training and instating workers according to their individual capabilities. This matching of machine requirements and worker skills serves to optimize the allocation of workers to workstations regarding the ergonomic workplace setup and the machine efficiency. This paper concludes with a user-friendly, intuitive design approach for a personalized machine user interface. The presented use-cases are developed and tested at the ARENA2036 (Active Research Environment for the Next Generation of Automobiles) research campus.