Motion Behavior and Range of Motion when Using Exoskeletons in Manual Assembly Tasks

Abstract

Although the automation level is high within the automotive industry, there are still a large number of manual tasks, especially is the final assembly of the vehicle. Overhead assembly operations is an example of a problematic manual task that can cause workers to develop musculoskeletal disorders in the shoulder complex. Exoskeletons may be a solution to reduce the risk for developing musculoskeletal disorders from the work tasks. This study evaluates and compares how the use of three different passive upper body exoskeletons affects the range of motion (ROM) of workers at overhead assembly tasks. An experiment consisting of three tasks was set up in order to analyze the differences between the models. Seventeen subjects were involved in the study. Interviews, observations, videos and motion capture recordings were the methods of collecting data. The results show agreement from all the subjects that the exoskeletons help the worker at this specific assembly operation. The results also show that different exoskeleton models cause different levels of ROM reductions. The subjects’ opinions about how the different exoskeletons influence the ROM corresponds with the analysis of the motion capture data. Positive and negative aspects of each exoskeleton from a ROM and an implementation point of view are discussed. In general, the results indicate that the exoskeleton models can be applicable for the type of work tasks studied. However, the exoskeletons would benefit from further development in order to decrease ROM limitations and therefore cover a larger number of different manual assembly tasks.

Biomechanical Effects of Using a Passive Exoskeleton for the Upper Limb in Industrial Manufacturing Activities: A Pilot Study

“…According to the recent review by Moeller (2022) [ 19 ], studies examining the effects of EXOs in occupational settings mostly focus on passive EXOs, primarily investigating muscle activity (shoulder, upper limb, and body) and secondarily exploring other kinematic, physiological, or usability parameters. According to the review, the Paexo device has been considered in three studies [ 28 , 29 , 30 ], which demonstrated (in lab assessment) its effectiveness in reducing shoulder muscle activity without negatively impacting trunk activity or compromising performance, eliciting favorable judgments from users.…”

Effects of Upper-Limb Exoskeletons Designed for Use in the Working Environment—A Literature Review

“…By using the Airframe Exoskeleton, McFarland et al ( 2022) reported a higher minimum shoulder elevation, a higher mean forearm pronation and a lower shoulder axial rotation angel. Furthermore, when comparing three different exoskeletons (ExoVest, Paexo Shoulder, Mate), the movement while wearing the Mate exoskeleton deviates most from the movement without exoskeleton in the shoulder joint (Perez Luque et al, 2020).…”

“…Furthermore, when comparing three different exoskeletons (EksoVest, Paexo Shoulder, Mate), 12 participants rated the Paexo and nine participants the ExoVest as the best supporting system for OHW. No participant voted in favour of the Mate Exoskeleton (Perez Luque et al, 2020). In another laboratory study (Daratany and Taveira 2020), the participants rated the usefulness of the exoskeleton at the overhead workstation (WS) after 8 min of use with 4-5.5 points on a 7-point scale.…”

“…In a further comparison (Perez Luque et al, 2020) with three models, users preferred exoskeletons that had the least kinematic deviation from movement without an exoskeleton. In contrast, an exoskeleton with the greatest deviation from normal movement had the lowest acceptance rate among users.…”

The Cognitive Operator 4.0

“…The use of exoskeletons can allow for more flexibility and efficiency in manual work tasks, reduce work-related injuries, and can also help overcome one of the major challenges in the western industry today, namely that of a changing demographic and an ageing workforce [2]. The current status of this technology is not however without challenges as they often limit the range of motion, cannot fully cope with a huge diversity of anthropometrics, and can, if not used properly, result in pressure injuries [9].…”