Proceeding of the 2018 Ergo-X Symposium : Exoskeletons in the Workplace\u2014Assessing Safety, Usability, and Productivity

"The Proceedings of the 2018 Ergo-X Symposium: Exoskeletons in the Workplace have been assembled to disseminate the speakers\u81' presentations and to summarize the question and answer/discussion periods that followed the presentations within each session. The proceedings appear by session and include summary points with links to presentation slides from speakers who agreed to provide them. The Ergo-X Proceedings Editors identified and documented the summary points and gave presenters of specific content (such as keynote presentations) an opportunity to review, edit, and approve the content. Here are some of the key summary points from the 2018 Ergo-X Symposium: 1. Metabolic demand may be a predictor of fatigue onset; however, we need a better understanding of how the positive or negative effect of an exoskeleton on metabolic demand affects injury prevention/risk. 2. The fit of the exoskeleton system is complex. Static assessments of fit that do not consider task dynamics are insufficient; multivariate anthropometric data are critical to fit. 3. Simulation and digital human modeling technologies have potential use in (1) assessing the interface between the user and exoskeleton and (2) reducing the test and evaluation burden of using human subjects. 4. Existing exoskeleton systems require a period of adaptation by the end user. For a new user, task performance is not likely to reach a steady state immediately. We need to establish acceptable test durations for exoskeleton trials. 5. Cognitive and psychomotor effects of exoskeleton use have been observed and are likely task dependent. 6. Industrial exoskeleton designs should be compatible with off-the-shelf tools, equipment, and personal protective equipment, rather than relying on specialty tools and custom interfaces. 7. Although industry speakers presented examples of wider-scale deployment of overhead support exoskeletons, overhead work with tool support appears to be the most mature industrial-use case at present. 8. The FDA oversees devices marketed/prescribed for medical use. Early adoption of medical exoskeletons may be more promising among individuals who are less adapted to other mobility-assistive technologies for their disabilities. 9. In the rehabilitation domain, clinics can utilize exoskeletons to assist therapists in delivering appropriate therapeutic doses. 10. ASTM Committee F48 on Exoskeletons and Exosuits and other standards organizations offer a forum for sharing exoskeleton knowledge. Feedback gathered from attendees and participants revealed 19 different topics (see the word cloud) that were issues or concerns for exoskeleton developers, researchers, and end users in 2018 and moving forward. The top four topics were (1) return on investment (ROI) considerations; (2) size, shape, and fit of exoskeletons on users; (3) longitudinal effects of exoskeleton usage; and (4) \u201cWhat metrics are right?\u201d for measuring safe, effective, or reliable system design and integration for users or patients." - NIOSHTIC-2NIOSHTIC no. 20057456Suggested citation: NIOSH [2019] Proceedings of the 2018 Ergo-X Symposium: Exoskeletons in the Workplace \u2014 Assessing Safety, Usability, and Productivity. By Lowe B, Billotte W, Brogmus G, McDowell T, Reid C, Rempel D, Srinivasan D (Editors). Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2020-102, https://doi.org/10.26616/NIOSHPUB20201022020-102.pdf?id=10.26616/NIOSHPUB2020102201910.26616/NIOSHPUB2020102678

A Review of Lower Limb Exoskeletons

In general, exoskeletons are defined as wearable robotic mechanisms for providing mobility. In the last six decades, many research work have been achieved to enhance the performance of exoskeletons thus developing them to nearly commercialized products. In this paper, a review is made for the lower limb exoskeleton concerning history, classification, selection and development, also a discussion for the most important aspects of comparison between different designs is presented. Further, some concluding remarks are withdrawn which could be useful for future work. Keywords: Exoskeletons, Lower extremity exoskeleton, Wearable robot

Int J Ind Ergon

Musculoskeletal Disorders (MSDs) remain a major concern for workers in the healthcare industry. Healthcare workers are at high risk of work-related MSDs mainly caused by overexertion from manually handling patients. Exoskeletons may be a useful tool to help reduce the risk of MSDs during patient handling. As a review study, we surveyed articles focusing on applying exoskeletons to patient handling tasks specifically. We also reviewed relevant government databases and other studies related to Safe Patient Handling and Mobility (SPHM) programs and exoskeleton applications in general. The exoskeletons specifically designed for patient handling were found to be sparse. To have a better understanding of the needs and challenges of developing and using exoskeletons for reducing risks of work-related MSDs in healthcare workers during patient handling, this critical review (1) provided an overview of the existing issues and projected future burdens related to work-related MSDs during patient handling tasks, (2) recognized current and potential roles and applications of existing exoskeletons, and (3) identified challenges and needs for future exoskeleton products. In conclusion, we do not expect exoskeletons to replace the existing SPHM programs, but rather play a complementary role to these multi-pronged programs. We expect that emerging exoskeleton products can be introduced to uncontrolled or specialized healthcare environments. There are various expectations and requirements for an exoskeleton used in different healthcare settings. Additionally, introducing certain types of exoskeletons for patients to assist them during treatment and rehabilitation may help reduce the MSD risks to the healthcare workers.CC999999/ImCDC/Intramural CDC HHSUnited States/2022-08-02T00:00:00Z35924209PMC934550711722vault:4305

Concept of an exoskeleton for industrial applications with modulated impedance based on Electromyographic signal recorded from the operator

The introduction of an active exoskeleton that enhances the operator power in the manufacturing field was demonstrated in literature to lead to beneficial effects in terms of reducing fatiguing and the occurrence of musculo-skeletal diseases. However, a large number of manufacturing operations would not benefit from power increases because it rather requires the modulation of the operator stiffness. However, in literature, considerably less attention was given to those robotic devices that regulate their stiffness based on the operator stiffness, even if their introduction in the line would aid the operator during different manipulations respect with the exoskeletons with variable power. In this thesis the description of the command logic of an exoskeleton for manufacturing applications, whose stiffness is modulated based on the operator stiffness, is described. Since the operator stiffness cannot be mechanically measured without deflecting the limb, an estimation based on the superficial Electromyographic signal is required. A model composed of 1 joint and 2 antagonist muscles was developed to approximate the elbow and the wrist joints. Each muscle was approximated as the Hill model and the analysis of the joint stiffness, at different joint angle and muscle activations, was performed. The same Hill muscle model was then implemented in a 2 joint and 6 muscles (2J6M) model which approximated the elbow-shoulder system. Since the estimation of the exerted stiffness with a 2J6M model would be quite onerous in terms of processing time, the estimation of the operator end-point stiffness in realtime would therefore be questionable. Then, a linear relation between the end-point stiffness and the component of muscle activation that does not generate any end-point force, is proposed. Once the stiffness the operator exerts was estimated, three command logics that identifies the stiffness the exoskeleton is required to exert are proposed. These proposed command logics are: Proportional, Integral 1 s, and Integral 2 s. The stiffening exerted by a device in which a Proportional logic is implemented is proportional, sample by sample, to the estimated stiffness exerted by the operator. The stiffening exerted by the exoskeleton in which an Integral logic is implemented is proportional to the stiffness exerted by the operator, averaged along the previous 1 second (Integral 1 s) or 2 seconds (Integral 2 s). The most effective command logic, among the proposed ones, was identified with empirical tests conducted on subjects using a wrist haptic device (the Hi5, developed by the Bioengineering group of the Imperial College of London). The experimental protocol consisted in a wrist flexion/extension tracking task with an external perturbation, alternated with isometric force exertion for the estimation of the occurrence of the fatigue. The fatigue perceived by the subject, the tracking error, defined as the RMS of the difference between wrist and target angles, and the energy consumption, defined as the sum of the squared signals recorded from two antagonist muscles, indicated the Integral 1 s logic to be the most effective for controlling the exoskeleton. A logistic relation between the stiffness exerted by the subject and the stiffness exerted by the robotic devices was selected, because it assured a smooth transition between the maximum and the minimum stiffness the device is required to exert. However, the logistic relation parameters are subject-specific, therefore an experimental estimation is required. An example was provided. Finally, the literature about variable stiffness actuators was analyzed to identify the most suitable device for exoskeleton stiffness modulation. This actuator is intended to be integrated on an existing exoskeleton that already enhances the operator power based on the operator Electromyographic signal. The identified variable stiffness actuator is the DLR FSJ, which controls its stiffness modulating the preload of a single spring

Appl Ergon

Low back disorders (LBDs) are a leading injury in the workplace. Back exoskeletons (exos) are wearable assist devices that complement traditional ergonomic controls and reduce LBD risks by alleviating musculoskeletal overexertion. However, there are currently no ergonomic assessment tools to evaluate risk for workers wearing back exos. Exo-LiFFT, an extension of the Lifting Fatigue Failure Tool, is introduced as a means to unify the etiology of LBDs with the biomechanical function of exos. We present multiple examples demonstrating how Exo-LiFFT can assess or predict the effect of exos on LBD risk without costly, time-consuming electromyography studies. For instance, using simulated and real-world material handling data we show an exo providing a 30 Nm lumbar moment is projected to reduce cumulative back damage by 3c70% and LBD risk by 3c20%. Exo-LiFFT provides a practical, efficient ergonomic assessment tool to assist safety professionals exploring back exos as part of a comprehensive occupational health program.R01 EB028105/EB/NIBIB NIH HHSUnited States/T42 OH008436/OH/NIOSH CDC HHSUnited States/T42OH008436/ACL/ACL HHSUnited States

Soft pneumatic elbow exoskeleton reduces the muscle activity, metabolic cost and fatigue during holding and carrying of loads

To minimize fatigue, sustain workloads, and reduce the risk of injuries, the exoskeleton Carry was developed. Carry combines a soft human–machine interface and soft pneumatic actuation to assist the elbow in load holding and carrying. We hypothesize that the assistance of Carry would decrease, muscle activity, net metabolic rate, and fatigue. With Carry providing 7.2 Nm of assistance, we found reductions of up to 50% for the muscle activity, up to 61% for the net metabolic rate, and up to 99% for fatigue in a group study of 12 individuals. Analyses of operation dynamics and autonomous use demonstrate the applicability of Carry to a variety of use cases, presumably with increased benefits for increased assistance torque. The significant benefits of Carry indicate this device could prevent systemic, aerobic, and/or possibly local muscle fatigue that may increase the risk of joint degeneration and pain due to lifting, holding, or carrying

Design and Development of a Lightweight Ankle Exoskeleton for Human Walking Augmentation

RESUMÉ La plupart des exosquelettes motorisés de la cheville ont une masse distale considérable, ce qui limite leur capacité à réduire l’énergie dépensée par l’utilisateur durant la marche. L’objectif de notre travail est de développer un exosquelette de chevilles avec le minimum de masse distale ajoutée comparé aux exosquelettes motorisés de chevilles existants. Aussi, l’exosquelette doit fournir au moins 50 Nm de support au couple de flexion plantaire. L’exosquelette développé dans le cadre de ce mémoire utilise deux câbles Bowden pour transmettre la force mécanique de l’unité d’actionnement attachée à la taille aux deux tiges en fibre de Carbonne attachées à la botte de l’utilisateur. Quand les deux tiges sont tirées, ils génèrent un couple qui supporte le mouvement de flexion plantaire à la fin de la phase d’appui du cycle de marche. Une pièce conçue sur mesure et imprimé en plastique par prototypage rapide a été attachée au tibia pour ajuster la direction des câbles. Une étude d’optimisation a été effectuée pour minimiser la masse des tiges limitant ainsi la masse distale de l’exosquelette (attaché au tibia et pied) à seulement 348 g. Le résultat principal obtenu à partir des tests de marche est la réduction de l’activité des muscles soléaire et gastrocnémien du sujet par une moyenne de 37% et 44% respectivement lors de la marche avec l’exosquelette comparée à la marche normale. Cette réduction s’est produite quand l’exosquelette a fourni une puissance mécanique de 19 ± 2 W avec un actionnement qui a commencé à 38% du cycle de marche. Ce résultat démontre le potentiel de notre exosquelette à réduire le cout métabolique de marche et souligne l’importance de réduire la masse distale d’un exosquelette de marche.----------ABSTRACT Most of powered ankle exoskeletons add considerable distal mass to the user which limits their capacity to reduce the metabolic energy of walking. The objective of the work presented in this master thesis is to develop an ankle exoskeleton with a minimum added distal mass compared to existing autonomous powered ankle exoskeletons, while providing at least 50 Nm of assistive plantar flexion torque. The exoskeleton developed in this master thesis uses Bowden cables to transmit the mechanical force from the actuation unit attached to the waist to the carbon fiber struts fixed on the boot. As the struts are pulled, they create an assistive ankle plantar flexion torque. A 3D-printed brace was attached to the shin to adjust the direction of the cables. A design optimization study was performed to minimize the mass of the struts, thereby limiting the total added distal mass, attached to the shin and foot, to only 348 g. The main result obtained from walking tests was the reduction of the soleus and gastrocnemius muscles activity by an average of 37% and 44% respectively when walking with the exoskeleton compared to normal walking. This reduction occurred when the exoskeleton delivered a mechanical power of 19 ± 2 W with an actuation onset fixed at 38% of the gait cycle. This result shows the potential of the proposed exoskeleton to reduce the metabolic cost of walking and emphasizes the importance of minimizing the distal mass of ankle exoskeletons

The Effect of Robotic Walking and Activity-based Rehabilitation on Functional Capacity, Secondary Complications & Psychological Well-being in Individuals with Spinal Cord Injury (SCI)

Activity-based training (ABT) represents the current standard of care in neurological rehabilitation centers around the world. However, innovative rehabilitation techniques have been developed including robotic locomotor training (RLT). The conceptual basis for RLT initially appeared promising; a rehabilitation modality that removes the need for intensive assistance from therapists, whilst facilitating safe and effective over-ground ambulation. However, small sample sizes and a lack of homogeneity across studies have resulted in an underpowered evidence base supporting the efficacy of RLT for SCI rehabilitation. Thus, this randomized control pilot study aimed to investigate the effects of RLT compared to ABT on functional capacity, secondary complications, and psychological well-being in people with SCI after 24-weeks of rehabilitation. Participants with chronic, traumatic motor incomplete SCI were randomized into two intervention groups: RLT (n = 8) and ABT (n = 8) groups. RLT involved solely walking in the Ekso bionic suit. ABT involved a variety of resistance, cardiovascular and flexibility training combined with regular weight-bearing in the standing position. Outcome measures, including functional strength, ambulatory function, pain, spasticity, bladder/bowel, bone density, body composition, quality of life (QoL) and depression were tested at baseline, 6, 12 and 24-weeks of the intervention. There were no significant differences between the intervention groups for lower or upper extremity motor scores (UEMS effect size (ES) = 0.30; LEMS ES = 0.07), back strength (ES = 0.14) and abdominal strength (ES = 0.13) after training. However, both groups showed a significant increase of 2.00 points in UEMS and a significant increase in abdominal strength from pre- to post intervention. Only the RLT group showed a significant change in LEMS, with a mean increase of 3.00 [0.00; 16.5] points over time. Distance walked in the Functional Ambulatory Inventory (SCI-FAI) increased significantly (p = 0.02) over time only for the RLT group. Therefore, the RLT showed promising evidence for potentially inducing functional strength changes and improvements in ambulatory function after 24 weeks of training. There was some evidence to support RLT to induce bowel improvements in individuals with SCI and both interventions appeared to reduce urinary incontinence and improve bladder function (p = 0.04). Total spasticity and pain intensity were similar between groups (p = 0.25; p = 0.96). However, pain interference ratings significantly increased from pre-post intervention for both groups (p = 0.05). RLT prevented the progressive decline of bone mineral density usually occurring in the SCI population, as hip BMD was maintained during RLT; however, it was significantly reduced (p = 0.04) during ABT, with a mean reduction of 0.06 [-0.34, 0.22] g/cm2 (5%) from pre to post intervention. No change in leg fat-free soft tissue mass (FFSTM) occurred between groups or over time (p = 0.32), however, there was a significant 7% increase in arm FFSTM over time for both groups (p < 0.01). The ABT group was more effective (ES = 1.02) in reducing central and peripheral adiposity, with a significant decrease in visceral adipose tissue (VAT) (p = 0.04) and gynoid FM (p = 0.01) over time. Both groups reported increased QoL and decreased depression ratings over time, with the RLT group having a significant change in the general life and physical health domains, p = 0.03, respectively. This pilot trial offers promising evidence for the effectiveness of RLT for improving functional and ambulatory capacity, reducing secondary complications, and potentially improving QoL in people with incomplete SCI. Thus, this dissertation adds substantial weight to the lacking evidence base on the effects of RLT, by incorporating a large homogenous sample, comprehensive testing procedures and an extended intervention period within South Africa