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Inertial Measurement Unit based Human Action Recognition for Soft-Robotic Exoskeleton

IOP Conference Series: Materials Science and Engineering 2021年第1期1140卷

作者： Jan Kuschan Moritz Burgdorff Hristo Filaretov Jörg Krüger Fraunhofer Institute for Production Systems and Design Technology IPK Germany

Absence from work caused by overloading the musculoskeletal system lowers the life quality of the worker and gains unnecessary costs for both the employer and the health system. Exoskeletons can present a solution. Typically, such systems struggle with stiffness and discomfort and primarily a lack of battery lifetime. Soft-robotic exoskeletons offer a possibility to overcome these problems by increasing the system flexibility, not limiting the supported DoF and being actuator and joint together. Since soft-robotic exoskeletons can be designed only using power when supporting the wearer, it is possible to increase the battery lifetime by only acting on those actions for which the wearer needs support. Dealing with controls for soft-robotic exoskeleton one major difficulty is to find a compromise between saving energy and supporting the wearer. Having an action-depending control can reduce the supported actions to cover only relevant ones and increase the lifetime of the battery. The system conditions are to detect the user actions in real-time and distinguish between actions which require support and those which do not. We contribute an analysis and modification of human action recognition (HAR) benchmark algorithms from activities of the daily living, transferred them onto industrial use cases containing short and mid-term action and reduce the models to be compatible using embedded computers for real-time recognition on soft exoskeletons. We identified the most common challenges for inertial measurement units based HAR and compare the best-performing algorithms using a newly recorded data set overhead car assembly for industrial relevance. As a benchmark data set we focused on the 'Opportunity' data set. By introducing orientation estimation, we were able to increase the F1 scores by up to 0.04. With an overall F1 score without a Null-class of up to 0.883, we were able to lay the foundation to use HAR for action dependent force support.

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AI-enhanced Identification, Inspection and Sorting for Reverse Logistics in Remanufacturing

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Procedia CIRP 2021年 98卷 300-305页

作者： Marian Schlüter Hannah Lickert Katharina Schweitzer Pinar Bilge Clemens Briese Franz Dietrich Jörg Krüger Fraunhofer IPK - Institute for Production Systems and Design Technology Pascalstr. 8-9 10587 Berlin Germany Technische Universität Berlin Institute for Machine Tools and Factory Management Pascalstr. 8-9 10587 Berlin Germany acatech – Deutsche Akademie der Technikwissenschaften Karolinenplatz 4 80333 München Germany

In a circular economy for remanufacturing, after each life cycle used products are returned to a remanufacturer for identification, inspection, sorting and reprocessing. Shortcomings and requirements of the remanufacturing market are identified through expert interviews and process analysis. A concept is proposed to enable an improved identification and a more objective inspection by enhancing the working environment and processes of sorting stations. Digitization and machine learning are applied on business data, using machine vision as well as sensor and actor skills of the worker. With an experimental case study on visual object recognition a positive impact on identification and thus sorting could be demonstrated.

关键词： Circular Economy Remanufacturing Reverse Logistics Sorting Computer Vision Machine Learning Assistance System

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Production environment of tomorrow (ProMo): Partially automated repair process of small tool moulds, forming tools, injection moulding tools and sand casting tools

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IOP Conference Series: Materials Science and Engineering 2021年第1期1140卷

作者： Jan Kuschan Vinzenz Müller Stephan Monchinger Oliver Heimann Carsten Niebuhr Oday Kabha Fraunhofer Institute for Production Systems and Design Technology IPK Germany

Small defects in the grain or major damage to a moulded part or tool can bring production to a standstill. SMEs in particular have neither the personnel nor the equipment to repair such damage on their own, so they send it to specialised contractors. The repair process is carried out manually, depending on the accuracy requirements, and is usually completed by a finishing process. This work requires qualified personnel and, at the same time, requires a lot of time in case of larger damages. In this paper we present a way to map the Maintenance, Repair and Operations (MRO) process chain in a partially automated manner. The symbiosis of individual technologies results in a significantly increased efficiency of the MRO process chain, which continues to focus on people and their process knowledge. While Directed Energy Deposition (DED) for the MRO of moulded parts is used widely, usually a high manual effort in measuring the component geometries and teaching of the machine tool paths is necessary. However, there are clear advantages compared to the manufacture of new parts or manual laser welding repair. At the same time, the resource and energy requirements can often be significantly reduced compared to new part production. Promo focuses on automating the time-consuming machine programming by reducing the number of necessary work steps in CAD/CAM-based program creation. Based on a subsequent robot-guided scan, a digital actual 3D model is generated. Due to intelligent path planning algorithms, no manual programming of the robot is necessary and at the same time it is possible to detect components of different sizes, shapes and covers in this system with a minimum of effort. In addition, the operator passes on elementary information, such as the approach path of the milling head, to the subsequent processes by means of finger gestures and can thus significantly reduce tedious CAM programming steps. Now, the scanned component is transferred to a 3D-CAD model and a target

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Data augmentation for inertial sensor based human action recognition using deep learning

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AIP Conference Proceedings 2024年第1期2989卷

作者： Jan Kuschan Hristo Filaretov Jörg Krüger Process Automation and Robotics Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 10587 Berlin Germany Industrial Automation Technology Institute of Machine Tools and Factory Management Technical University Berlin Pascalstr. 8-9 10587 Berlin Germany

Human Activity Recognition (HAR) approaches are predominantly based on supervised deep learning and benefit from large amounts of labeled data—an expensive resource. Data augmentation enriches labeled datasets by adding synthetic data, which is substantially cheaper, and often results in improved model performance, but is very rarely used for sensor data. This work explores data augmentation for inertial-sensor-based HAR by transforming the data through physically interpretable operations. The main studies were conducted on the Opportunity and the Overhead Car Assembly (OCA) datasets. For these experiments, only 20% of the available training data were used, and the experiments were conducted in an 8-fold cross-validation procedure over different subsets of the training *** results show that simple geometric augmentations can be beneficial in many cases. Timewarping proved to offer the most reliable single augmentation, improving the average F1 score of Opportunity from 0.570 to 0.597 and of OCA Mixed from 0.884 to 0.906. Combining augmentations improved the accuracy in almost all scenarios but to a degree comparable to timewarping. Applying augmentations on all the available training data improved the F1 score compared to the base case with no augmentations, although this effect is more pronounced for datasets with more similar training and test data: for the OCA Mixed variant, the average F1 score improved from 0.917 to 0.933, while for the OCA Leave-One-Out (LOT) variant, the average F1 score did not significantly change. For Opportunity, which similarly to OCA LOT uses a participant-based training-test split, the F1 score improved from 0.684 to 0.697.

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User centered development of a Digital Twin concept with focus on sustainability in the clothing industry

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Procedia CIRP 2020年 90卷 660-665页

作者： Theresa Riedelsheimer Lisa Dorfhuber Rainer Stark Fraunhofer-Institute for Production Systems and Design Technology (IPK) Pascalstrasse 8-9 10587 Berlin Germany Technical University Berlin Pascalstrasse 8-9 10587 Berlin Germany

The optimization of a product's socio-economic and environmental impact is gaining more relevance for customers and regulating institutions. Still, there is a gap between sustainable attitude and behavior. In this context, new technologies are explored to stimulate sustainable consumers' behavior. This paper aims at analyzing the concept of a Digital Twin and its sustainability impact. The authors present a user centered development of a Digital Clothing Twin with the aim to foster sustainability in the Mid-of-life and End-of-Life-phase. The sustainability impact of the Digital Twin concept as a potential solution as well as part of the problem is discussed.

关键词： Life Cycle Sustainability Assessment (LCSA) Life Cycle Assessment (LCA) Digital Twin Sustainability Smart products Use case

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Production in the loop-the interoperability of digital twins of the product and the production system 14

Production in the loop-the interoperability of digital twins...

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14th CIRP Conference on Intelligent Computation in Manufacturing Engineering, CIRP ICME 2020

作者： Vogt, Anna Schmidt, Philipp Heiner Mayer, Sebastian Stark, Rainer Audi AG Auto-Union-Str. 1 Ingolstadt85045 Germany Technical University of Berlin Department of Industrial Information Technology Pascalstraße 8-9 Berlin10587 Germany Volkswagen AG Berliner Ring 2 Wolfsburg38436 Germany Technical University of Kaiserslautern Institute for Virtual Product Engineering Gottlieb-Daimler-Straße 44 Kaiserslautern67663 Germany Technische Hochschule Ingolstadt Institute for Innovative Mobility Esplanade 10 Ingolstadt85049 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstraße 8-9 Berlin10587 Germany

The Internet of Things (IoT) era facilitates new possibilities at the interface between the lifecycle of the product and the manufacturing disciplines allowing to add value and meet growing legal requirements. This work presents use cases from the automobile industry which are analyzed in order to derive requirements for data exchange. The analysis of the use cases shows clearly that we need to focus on the instance level for this purpose. This means that both, a specific unit of the product and the production system, must be considered. As a solution approach, a communication loop is proposed bringing the Digital Twin concept in a new field of usage. The key aspect of the proposed solution is the direct intercommunication between the Digital Twins of the product being produced as a Cyber-Physical System (CPS) and the production resources as Cyber-Physical Production Systems (CPPS). This solution enables the aggregation of production-related data within the products Digital Twin and therefore promotes maximal transparency throughout engineering disciplines, phases of the product lifecycle and the whole supply chain. © 2021 The Authors. Published by Elsevier B.V.

关键词： Cyber Physical System

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Demand-oriented barriers and potentials for remanufacturing in Vietnam

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International Journal of Sustainable Manufacturing 2020年第2-4期4卷 336-349页

作者： Guidat, Thomas Wewer, Aleksandra Kohl, Holger Seliger, Günther Department of Machine Tools and Factory Management Technische Universität Berlin Pascalstraße 8-9 Berlin10587 Germany Vietnamese German University Lê Lai Đinh Hoà Thů Dâu Môt Bình Dương Viet Nam Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstraße 8-9 Berlin10587 Germany

Since the liberalisation of its economy, Vietnam has emerged as a key location for investment in workforce-intensive assembly processes operation, through an available and cheap workforce. Soaring national consumption levels for goods and services generate in turn unprecedented quantities of waste to be treated locally. In 2015, governmental decision 16/2015/QĐ-TTg set a basis for a national waste legislation for mechanical and electronic equipment goods. Remanufacturing is a non-destructive, industrial reuse strategy which aims at restoring products to original specifications by reusing a maximum number of original components in their current form. It has potential to provide Vietnam with an alternative to low value-added repair activities. As Vietnam is the fourth market for motorcycles in the world, this paper presents a case study about barriers and potentials for remanufacturing from the market and customer perspective. Potential solutions for supporting industrial development are suggested. © 2020 Inderscience Enterprises Ltd.

关键词： Motorcycles

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Safe high impedance control of a series-elastic actuator with a disturbance observer

Safe high impedance control of a series-elastic actuator wit...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Kevin Haninger Abner Asignacion Sehoon Oh Division of Automation Technology Fraunhofer Institute for Production Systems and Design Technology (IPK) Berlin Germany Department of Robotic Engineering Daegu Gyeongbuk Institute of Science and Technology Daegu Korea

ISBN: (数字)9781728173955

ISBN: (纸本)9781728173962

In many series-elastic actuator applications, the ability to safely render a wide range of impedance is important. Advanced torque control techniques such as the disturbance observer (DOB) can improve torque tracking performance, but their impact on safe impedance range is not established. Here, safety is defined with load port passivity, and passivity conditions are developed for two variants of DOB torque control. These conditions are used to determine the maximum safe stiffness and Z-region of the DOB controllers, which are analyzed and compared with the no DOB case. A feedforward controller is proposed which increases the maximum safe stiffness of the DOB approaches. The results are experimentally validated by manual excitation and in a high-stiffness environment.

关键词： Impedance Torque Torque control Springs Stability analysis Safety Measurement

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Micro-cutting of a MMC-composite for enhanced injection moulds 19

Micro-cutting of a MMC-composite for enhanced injection moul...

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19th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2019

作者： Uhlmann, E. Polte, M. Hein, C. Polte, J. Jahnke, C. Fraunhofer Institute for Production Systems and Design Technology IPK Germany Institute for Machine Tools Factory Management IWF Technische Universität Berlin Germany

ISBN: (纸本)9780995775145

Tools for micro-injection moulding are currently made of hardened steel. These tools are exposed to high local loads, which significantly reduce the injection moulding tool life time tT. Furthermore, the occurring wear of the milling tool during machining of hardened steel leads to reduced surface roughness Ra and geometrical accuracy GF. Copper and aluminium alloys as mould materials provide an alternative to hardened steel with advantages regarding material removal rate QW and wear of the milling tool, but with a significantly reduced life time of the injection moulding tool tT. Until now, the combination of a good machinability and high wear resistance cannot be achieved. The approach, presented in this paper consists of an easy to machine material and the development of a wear resistant metal-matrix-composite (MMC) material layer with a hardness of up to 3,000 HV. Therefore, the pre-machined test specimens made of aluminium-bronze are coated by laser dispersing with wolfram-carbide-particles W2C-WC. Furthermore, for the finishing machining of the coated moulds, a cutting technology for the machining of W2C-WC-particles was developed. The verification of the developed technology was performed with an injection moulding process based on carbon-fibre reinforced thermoplastic material. By means of documented machining efforts, the quality indicators geometrical accuracy GF and surface roughness Ra as well as occurring tool wear, the feasibility of the developed technology was demonstrated. © 2019 European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 19th International Conference and Exhibition, EUSPEN 2019. All rights reserved.

关键词： Injection molding

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Cutting force predictionin micro-milling considering the cutting edge micro-geometry 19

Cutting force predictionin micro-milling considering the cut...

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19th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2019

作者： Uhlmann, E. Polte, J. Wiesner, H.M. Kuche, Y. Polte, M. Fraunhofer Institute for Production Systems and Design Technology IPK Germany Institute for Machine Tools Factory Management IWF Technische Universität Berlin Germany

ISBN: (纸本)9780995775145

The micro-milling process is used for a wide range of materials and enables the manufacturing of complex geometries with micro-features. One important factor for the tool life is the cutting force Fc, which depends on the applied technology, process parameters and cutting edge micro-geometry. High cutting forces Fc can lead to tool breakage in the transition between the shank and the cutting part of cemented carbide end mills. The prediction of cutting forces Fc in micro-milling processes through cutting force models could potentially decrease the hazard of tool breakage. By including the cutting edge radius rβ into the prediction model, additional correction factors can be avoided. Therefore, further knowledge about the applicability of those models for the micro-milling process with chip thickness h © 2019 European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 19th International Conference and Exhibition, EUSPEN 2019. All rights reserved.

关键词： Milling (machining)

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