Development of an Acceptance Model for Occupational Exoskeletons and Application for a Passive Upper Limb Device

OCCUPATIONAL APPLICATION Occupational exoskeletons may help reduce the physical demands of work, but several challenges exist in their workplace integration. While there is evidence that wearing an exoskeleton can reduce perceptions of effort and muscle fatigue, exoskeletons can negatively affect user acceptance if they increase local discomfort or do not provide sufficient adjustability. Additionally, most existing evidence is from laboratory settings, which has unknown validity for real work activities. To address these limitations, we completed a field study to identify key acceptance factors in real contexts of use, as well as methods for measurement. From our results, we present acceptance factors in a model centered on four aspects concerning the use of an occupational exoskeleton, a global methodology for factor identification, and propose easy measurement methods for practitioners. These outputs provide new ergonomics specifications for human–exoskeleton interaction in the early use stage. TECHNICAL ABSTRACT Background: To address the high costs of work-related musculoskeletal disorders, several industries have started to experiment with exoskeletons, but have faced technical and psychological barriers. The design of efficient and usable exoskeletons needs to account for both technical constraints and more subtle requirements related to their acceptance by users. Existing models of acceptability, essentially based on predictive methods and information sciences, were not considered relevant for the case of occupational exoskeletons. Purpose: The purpose of this study was to specify an acceptance model adapted to occupational exoskeletons, in order to facilitate their evaluation during the initial phase of use in the field. Methods: We employed an ecological approach. Because of the physical interaction the user experiences with an exoskeleton and within the working situation, acceptance criteria were developed from actual field use. Initially, an action research process was completed to identify key determinants in the field. New factors, missing in existing acceptability models, were added to a proposed new model, together with methods for their measurement. To test the new model, an experiment was completed on manual operations in an industrial context and partly in a laboratory. Results: We organized the identified factors into an acceptance model, which was then validated and completed by exoskeleton experts in ergonomics based on four aspects: physical, occupational, cognitive, and affective. Conclusions: This new model, focused on usability, is based on easy-to-implement methods and could, therefore, be of use to diverse stakeholders (exoskeleton designers, ergonomists, etc.). Based on a real use approach, such a model makes it easier to evaluate the human–exoskeleton system, and could thus facilitate more successful adoption by companies.