Now showing 1 - 5 of 5
  • Publication
    Metadata only
    Methodologies for evaluating exoskeletons with industrial applications
    (2022-02)
    Hoffmann, Niclas
    ;
    Prokop, Gilbert
    ;
    Industrial exoskeletons are globally developed, explored, and increasingly implemented in industrial workplaces. Multiple technical, physical, and psychological aspects should be assessed prior to their daily application in various occupational environments. The methodology for evaluating these aspects is not standardised and differs in terms of focussed research objectives, used types of analyses, applied testing procedures, and use cases. The aim of this paper is to provide a matrix comparing the prevalence of different types of analyses combined with their respective research objective(s). A systematic review in the database 'Web of Science' identified 74 studies, mainly in laboratory settings, with a focus on short-term effects as well as with male-dominated samples being low representative for industrial workforces. The conducted evaluation methodologies are further discussed and compared in terms of testing procedure, sample, and research objectives. Finally, relevant aspects for prospectively evaluating industrial exoskeletons in a more harmonised and comprehensive way are suggested. Practitioner summary: Industrial exoskeletons are still inconsistently and insufficiently evaluated in scientific studies, which might hamper the comparability of systems, threaten the human health, and block an iterative system optimisation. Thus, a comprehensive evaluation methodology is needed with harmonised and multicriteria types of analyses.
  • Publication
    Metadata only
    Low-Cost Force Sensors Embedded in Physical Human-Machine Interfaces: Concept, Exemplary Realization on Upper-Body Exoskeleton, and Validation
    (2022-01-10)
    Hoffmann, Niclas
    ;
    Ersoysal, Samet
    ;
    Prokop, Gilbert
    ;
    Hoefer, Matthias
    ;
    In modern times, the collaboration between humans and machines increasingly rises, combining their respective benefits. The direct physical support causes interaction forces in human-machine interfaces, whereas their form determines both the effectiveness and comfort of the collaboration. However, their correct detection requires various sensor characteristics and remains challenging. Thus, this paper presents a developed low-cost sensor pad working with a silicone capsule and a piezoresistive pressure sensor. Its measurement accuracy is validated in both an isolated testing environment and a laboratory study with four test subjects (gender-balanced), and an application integrated in interfaces of an active upper-body exoskeleton. In the material-testing machine, it becomes apparent that the sensor pad generally features the capability of reliably determining normal forces on its surface until a certain threshold. This is also proven in the real application, where the measurement data of three sensor pads spatially embedded in the exoskeletal interface are compared to the data of an installed multi-axis load cell and a high-resolution flexible pressure map. Here, the consideration of three sensor pads potentially enables detection of exoskeletal support on the upper arm as well as "poor" fit conditions such as uneven pressure distributions that recommend immediate system adjustments for ergonomic improvements.
  • Publication
    Unknown
    Towards a Database for Deriving Design Aspects of Industrial Exoskeletons
    (2022)
    Hoffmann, Niclas
    ;
    Calisti, Maité
    ;
    Reimeir, Benjamin
    ;
    Ralfs, Lennart
    ;
  • Publication
    Unknown
    Method and test course for the evaluation of industrial exoskeletons
    (2021-10-01)
    Ralfs, Lennart
    ;
    Hoffmann, Niclas
    ;
    In recent years, the trend for implementing exoskeletons in industrial workplaces has significantly increased. A variety of systems have been developed to support different tasks, body parts, and movements. As no standardized procedure for evaluating industrial exoskeletons is currently available, conducted laboratory and field tests with different setups and methodologies aim to provide evidence of, e.g., the support for selected isolated activities. Accordingly, a comparison between exoskeletons and their workplace applicability proves to be challenging. In order to address this issue, this paper presents a generic method and modular test course for evaluating industrial exoskeletons: First, the seven-phase model proposes steps for the comprehensive evaluation of exoskeletons. Second, the test course comprises a quick check of the system’s operational requirements as well as workstations for an application-related evaluation of exoskeletons’ (short-term) effects. Due to the vastness and heterogeneity of possible application scenarios, the test course offers a pool of modular configurable stations or tasks, and thus enables a guided self-evaluation for different protagonists. Finally, several exemplary exoskeletons supporting varying body regions passed the test course to evaluate and reflect its representativity and suitability as well as to derive discernible trends regarding the applicability and effectiveness of exoskeleton types.