Kinematic and dynamic assessment of trunk exoskeleton

In Industry 4.0, wearable exoskeletons have been proposed as collaborative robotic devices to partially assist workers in heavy and dangerous tasks. Despite the recent researches, proposed prototypes and commercial products, some open issues concerning development, improvements and testing still exist. The current pilot study proposed the assessment of a proper biomechanical investigation of passive trunk exoskeleton effects on the human body. One healthy subject performed walking, stoop and semisquat tasks without, with exoskeleton no support and with exoskeleton with support. 3D Kinematic (angles, translations) and dynamic (interface forces) parameters of both human and exoskeleton were estimated. Some differences were pointed out comparing task motions and exoskeleton conditions. The presented preliminary test revealed interesting results in terms of different human joints coordination, interface forces exchanged at contact points and possible misalignment between human and device. The present study could be considered as a starting point for the investigation of exoskeleton effectiveness and interaction with the user

Powered exoskeleton for trunk assistance in industrial tasks

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Back and shoulder exoskeletons for occupational use: a review

Work-related musculoskeletal disorders (MSDs) account for a large portion of all work-related injuries according to OSHA. Back and shoulder-related disorders make the most of work-related MSDs according to the Bureau of Labor Statistics (BLS). Exoskeletons emerged in recent years with the potential to reduce the risks of work-related musculoskeletal disorders and injuries. Their use in occupational settings is increasing, and exoskeleton designs are rapidly evolving. This paper reviewed recent scientific articles (2015 and after) that evaluated back and shoulder-support passive industrial exoskeletons. The findings of these articles are summarized and analyzed to assess the benefits of passive upper-body exoskeletons by identifying agreements and disagreements through these articles. Seven BSEs (back support exoskeleton) through 16 articles and eight SSEs (shoulder support exoskeleton) through 14 articles are reviewed. It is concluded through these articles that passive upper body exoskeletons can provide benefits with selected short-term manual handling tasks in industry settings. The benefits are more pronounced with quantitative assessments. Scientific studies aim to gather further data such as metabolic cost, oxygen consumption, and heart rate along with muscle load assessments to present clearer and more complete results. However, there is not enough data through the recent articles to make any clear conclusions about exoskeletons’ benefits in real-life working conditions for long term uses. Benefits can change with the design and task dramatically. However, none of these exoskeletons have presented a clear superiority to each other in these studies. Specifics of tasks and conditions should be considered to determine the most suitable exoskeleton

Effects of a passive back exoskeleton on the mechanical loading of the low-back during symmetric lifting

Low-back pain is the number one cause of disability in the world, with mechanical loading as one of the major risk factors. Exoskeletons have been introduced in the workplace to reduce low back loading. During static forward bending, exoskeletons have been shown to reduce back muscle activity by 10% to 40%. However, effects during dynamic lifting are not well documented. Relative support of the exoskeleton might be smaller in lifting compared to static bending due to higher peak loads. In addition, exoskeletons might also result in changes in lifting behavior, which in turn could affect low back loading. The present study investigated the effect of a passive exoskeleton on peak compression forces, moments, muscle activity and kinematics during symmetric lifting. Two types (LOW and HIGH) of the device, which generate peak support moments at large and moderate flexion angles, respectively, were tested during lifts from knee and ankle height from a near and far horizontal position, with a load of 10 kg. Both types of the trunk exoskeleton tested here reduced the peak L5S1 compression force by around 5-10% for lifts from the FAR position from both KNEE and ANKLE height. Subjects did adjust their lifting style when wearing the device with a 17% reduced peak trunk angular velocity and 5 degrees increased lumbar flexion, especially during ANKLE height lifts. In conclusion, the exoskeleton had a minor and varying effect on the peak L5S1 compression force with only significant differences in the FAR lifts

Occupational Exoskeletons: Understanding the Impact on Workers and Suggesting Guidelines for Practitioners and Future Research Needs

This paper examines occupational exoskeletons and their effects on workers. The study includes a thorough evaluation of the current literature on occupational exoskeletons, with an emphasis on the impact of these devices on workers’ health and the safety, performance and users’ subjective perceptions. The aim of the study was to gain knowledge of how exoskeletons affect the workers and to identify practical suggestions for practitioners. The findings of the study suggest that exoskeletons can have both positive and negative effects on workers. Some users claimed enhanced comfort and decreased fatigue, whilst others reported discomfort and suffering. The study highlights the importance of considering the individual needs and preferences of workers when selecting and implementing exoskeletons in the workplace, with a focus on health, safety, performance and user acceptance. Based on the findings, the paper presents suggestions for employers and practitioners to ensure the effective and safe use of exoskeletons in occupational settings. These recommendations cover areas such as the assessment of workplace requirements, the selection and fit of exoskeletons, the optimization of design and ergonomics and the evaluation of performance. The paper concludes by highlighting the need for further research in this area, particularly in the areas of long-term use

Modeling and Design of a Spring-loaded, Cable-driven, Wearable Exoskeleton for the Upper Extremity

An approach to the design of wearable exoskeletons on the basis of simulation of the exoskeleton and a human body model is proposed in this paper. The new approach, addressing the problem of physical human-exoskeleton interactions, models and simulates the mechanics of both the exoskeleton and the human body, which allows designers to effectively analyze and evaluate an exoskeleton design for their function in concert with the human body. A simulation platform is developed by integrating a biomechanical model of the human body and the exoskeleton. With the proposed approach, an exoskeleton is designed for assisting patients with neuromuscular injuries. Results of the analysis and optimization are included

Design of a Passive Exoskeleton Spine

In this thesis, a passive exoskeleton spine was designed and evaluated by a series of biomechanics simulations. The design objectives were to reduce the human operator’s back muscle efforts and the intervertebral reaction torques during a full range sagittal plane spine flexion/extension. The biomechanics simulations were performed using the OpenSim modeling environment. To manipulate the simulations, a full body musculoskeletal model was created based on the OpenSim gait2354 and “lumbar spine” models. To support flexion and extension of the torso a “push-pull” strategy was proposed by applying external pushing and pulling forces on different locations on the torso. The external forces were optimized via simulations and then a physical exoskeleton prototype was built to evaluate the “push-pull” strategy in vivo. The prototype was tested on three different subjects where the sEMG and inertial data were collected to estimate the muscle force reduction and intervertebral torque reduction. The prototype assisted the users in sagittal plane flexion/extension and reduced the average muscle force and intervertebral reaction torque by an average of 371 N and 29 Nm, respectively