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(a) Mechanical design of hip joint: (i) quasi-direct drive motor, (ii) connecting element from lumbar support backrest to hip joint, (iii) motor flange, and (iv) connecting element from hip to thigh. (b) The FEA result of total deformation of flat.
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Lumbar Exoskeleton, as an important instance of wearable exoskeleton, has broad application prospects in logistics, construction, and other industries. Specifically, in the working scenarios that require long-term and repeated bending and rising movements, active lumbar exoskeleton (ALE) can provide effective protection and flexible assistance to w...
Citations
... Ji et al. [86] fabricated a portable exoskeleton that adapts to a human body in order to assist in lifting objects from the ground and avoid various musculoskeletal conditions. The objectives of the study were, first, the correct human-machine interaction in terms of the movements, and second, the correct placement of the exoskeleton on the human body. ...
In recent years, the rapid advancement of technology has caused an increase in the development of wearable products. These are portable devices that can be worn by people. The main goal of these products is to improve the quality of life as they focus on the safety, assistance and entertainment of their users. The introduction of many new technologies has allowed these products to evolve into many different fields with multiple uses. The way in which the design of wearable products/devices is approached requires the study and recording of multiple factors so that the final device is functional and efficient for its user. The current research presents an in-depth overview of research studies dealing with the development, design and manufacturing of wearable products/devices and applications/systems in general. More specifically, in this review, a comprehensive classification of wearable products/devices in various sectors and applications was carried out, resulting in the creation of eight different categories. A total of 161 studies from the last 13 years were analyzed and commented on. The findings of this review show that the use of new technologies such as 3D scanning and 3D printing are essential tools for the development of wearable products. In addition, many studies observed the use of various sensors through which multiple signals and data could be recorded. Finally, through the eight categories that the research studies were divided into, two main conclusions emerged. The first conclusion is that 3D printing is a method that was used the most in research. The second conclusion is that most research directions concern the safety of users by using sensors and recording anthropometric dimensions.
... In recent years, lumbar exoskeleton (LEXO) is developed to assist in lumbar movement. It showed potential to relieve muscle fatigue and improve work efficiency by reducing the workload for low back muscles [3][4][5]. ...
... In order to accurately evaluate the effect of lumbar exoskeleton on low back muscles and improve the exoskeleton system, activities of low back muscles were often measured and analyzed. The researchers generally recorded surface electromyography (sEMG) from low back muscles to view the muscle activities [3][4][5][6][7][8]. After wearing a passive lumbar exoskeleton, there showed a significant reduction in the root mean square (RMS), zero-crossing rate, mean frequency, median frequency of sEMG from some paraspinal muscles during lifting movement [6]. ...
... The lumbar exoskeleton used in this study is produced in our lab ( Fig. 1). It is an active lumbar exoskeleton (weight: 4.9kg) which can provide assistance and protection for the wearer's lumbar vertebrae joints during lumber movement [3]. The lumbar exoskeleton is composed of the following three sub-modules: (a) physical human-robot interface, (b) principle of assistance, and (c) control strategy. ...
Lumbar exoskeleton has potential to assist in lumbar movements and thereby prevent impairment of back muscles. However, due to limitations of evaluation tools, the effect of lumbar exoskeletons on coordinated activities of back muscles is seldom investigated. This study used the surface electromyography (sEMG) topographic map based on multi-channel electrodes from low back muscles to analyze the effects. Thirteen subjects conducted two tasks, namely lifting and holding a 20kg-weight box. For each task, three different trials, not wearing exoskeleton (NoExo), wearing exoskeleton but power-off (OffExo), and wearing exoskeleton and power-on (OnExo), were randomly conducted. Root-mean-square (RMS) and median-frequency (MDF) topographic maps of the recorded sEMG were constructed. Three parameters, average pixel values, distribution of center of gravity (CoG), and entropy, were extracted from the maps to assess the muscle coordinated activities. In the lifting task, results showed the average pixel values of RMS maps for the NoExo trial were lower than those for the OffExo trial (p<0.05) but the same as those for the OnExo trial (p>0.05). The distribution of CoG showed a significant difference between NoExo and OnExo trials (p<0.05). In the holding task, RMS and MDF maps’ average pixel values showed significant differences between NoExo and OnExo trials (p<0.05). These findings suggest that active lumbar exoskeletons can reduce the load on low back muscles in the static holding task rather than in the dynamic lifting task. This proves sEMG topographic maps offer a new way to evaluate such effects, thereby helping improve the design of lumbar exoskeleton systems.
... For example, Antwi-Afari et al. (2021) reported a significant reduction in back muscle activity after assessing a passive exoskeleton during regular repetitive manual handling construction tasks (lifting loads in different postures). In similar experimental tests, demands on the shoulders were reduced during an overhead task (Abdulkarim et al., 2019), during single and double-leg kneeling tasks (Chen et al., 2021), and demands to worker's waist muscles and bones were reduced during repeated bending and rising movements (Ji et al., 2020). In addition, Gonsalves et al. (2021) investigated the impact of passive exoskeletons on worker fatigue and discovered that exoskeletons could reduce muscle activation and improve worker productivity. ...
... The passive actuators mostly utilized passive components such as springs, dampers, and the elastic band as an assistive source in the lumbar support exoskeleton. Since the passive actuators are not able to provide sufficient assistance to muscle activity [5], the active actuators have been developed to generate higher power assistance to the human body by using an external power source to supply the actuators. Different types of active actuators have been used in the lumbar support exoskeleton to augment the human muscle, for example, electric motors, pneumatic artificial muscles (e.g., Muscle Suit [6]), hydraulic actuators, and soft actuators [7]. ...
Assistive exoskeletons are rapidly being developed to collaborate with humans, and the demand for the safety of human-robot interaction has become more crucial. Series elastic actuators (SEAs) have recently been developed for various possible advantages, such as providing a safe human-robot interaction, reducing the impacts' effects, and increasing energy efficiency. However, achieving good dynamic performances of SEAs is still challenging, especially in fulfilling the high bandwidth with good compliance. In this rapidly growing research field, the actuation system involving the storage device combined with the rotary series elastic actuator (ES-RSEA) is being investigated to exploit the biomechanical energy while maintaining compliance features. In this article, the modeling and control design of the energy storage rotary series elastic actuator (ES-RSEA) for the lumbar support exoskeleton is proposed, and its dynamic performances are analyzed. The ES-RSEA was designed to store kinetic energy during lifting tasks and generate assistive torque while maintaining excellent compliant characteristics. The dynamic performances and characteristics of ES-RSEA are presented in terms of force sensitivity, level of compliance, transmission ratio, and bandwidth. Simulation studies indicate that the actuator can provide excellent dynamic performance through its high bandwidth (12.44 Hz) and high force sensitivity. At the same time, it shows excellent compliance and good torque transmissibility in the low-frequency range. A PID controller can achieve high torque tracking performance and good dynamic response with a root-mean-square (RMS) error of 0.1 N.m. This article demonstrates the excellent performance and characteristics of ES-RSEA to guarantee compliance and high response to prevent injury of undesired human movements.
... In this context, back exoskeletons are a promising solution to assist and support workers during specific task reducing human physical efforts. Both passive and active exoskeletons had been considered [8,9]. Despite passive actuation being cheaper, lightweight and less complex, active systems allow to achieve high flexibility and to ensure more and customizable applications [10]. ...
Wearable robotics is one of the Industry 4.0 pillars for performing tasks that cannot yet be fully automated. This category includes trunk exoskeletons, devices that can be worn directly by the user with the aim of partially reducing low-back muscular efforts and avoiding work-related injuries. Active exoskeletons allow a good support adaptability to suit user’s request, certifying the relevance of a control law able to modulate the assistance also compensating the disturbances. The aim of this study is to experimentally characterize active joints of a trunk exoskeleton prototype to obtain a model able to describe their real behaviour and non-linearities. This identification is essential to develop an adaptable and disturbance-free control law that ensures the flexible desired support.
... Additionally there are deep spinal muscles that cannot be recorded from using surface EMG sensors. The choice of which metric to extract from the EMG signal is also problematic, with some studies choosing signal peaks Thamsuwan et al. 2020;Lazzaroni et al. 2019), others integrate or take the root-mean-squared of the signal over the lifting task (von Glinski et al. 2019;Yong et al. 2019;Ji et al. 2020), some use the mean or median of the signal (Poliero et al. 2020;Baltrusch et al. 2020;Baltrusch et al. 2019;Chen et al. 2018), and two took the average of the 90 th percentile of the signal (Madinei et al. 2020;Di Natali et al. 2021). The choice of metric was not related to whether or not a study found a positive result. ...
... von Glinski et al. 2019), four studies observed reductions of 30-40%Yong et al. 2019;Chen et al. 2018), and two 40-60% (DiNatali et al. 2021;Ji et al. 2020). ...
Advances in assistive exoskeleton technology, and a boom in related scientific literature, prompted a need to review the potential use of exoskeletons in defence and security. A systematic review examined the evidence for successful augmentation of human performance in activities deemed most relevant to military tasks. Categories of activities were determined a priori through literature scoping and Human Factors workshops with military stakeholders. Workshops identified promising opportunities and risks for integration of exoskeletons into military use cases. The review revealed promising evidence for exoskeletons' capacity to assist with load carriage, manual lifting, and working with tools. However, the review also revealed significant gaps in exoskeleton capabilities and likely performance levels required in the use case scenarios. Consequently, it was recommended that a future roadmap for introducing exoskeletons to military environments requires development of performance criteria for exoskeletons that can be used to implement a human-centred approach to research and development.
... During long-term lifting activity, the exoskeleton is reported to decrease stress and lumbar muscle strain. In the updated model SIAT-WEXv2, a 48% reduction of muscle activity of Lumbar erector spinae was achieved (Ji et al., 2020). ...
Lower back pain and musculoskeletal injuries are serious concerns for workers subjected to physical workload and manual material handling tasks. Spine assistive exoskeletons are being developed to support the spine and distribute the spine load. This article presents a detailed up-to-date review on the back support exoskeletons by discussing their type (Active/Passive), structure (Rigid/Soft), power transmission methods, weight, maximum assistive force, battery technologies, tasks (lifting, bending, stooping work), kinematic compatibility and other important features. This article also assesses the back support exoskeletons in terms of their ability to reduce the physical load on the spine. By reviewing functional and structural characteristics, the goal is to increase communication and realization among ergonomics practitioners, developers, customers, and factory workers. The search resulted in reviewing 34 exoskeletons of which 16 were passive and 18 were active. In conclusion, back support exoskeletons have immense potential to significantly reduce the factors regarding work-related musculoskeletal injuries. However, various technical challenges and a lack of established safety standards limit the wide adaptation of exoskeletons in industry.
... In 2019 and 2020, 36 and 38 included papers were published, respectively. The included papers comprised 51 validation studies (Aida et al., 2009;Blanco et al., 2019;De Busk et al., 2017;de Vries et al., 2019;Ebrahimi et al., 2017;Han et al., 2019Han et al., , 2020Hao et al., 2020;Hondzinski et al., 2019;Hull et al., 2020;Huysamen et al., 2018a;Inose et al., 2017;Inoue and Noritsugu, 2018;Jeong et al., 2020;Johnson et al., 2018;Kazerooni et al., 2019;Kim et al., 2015Kim et al., , 2020aKobayashi and Nozaki, 2008;Koopman et al., 2019b;Kosaki and Li, 2020;Kudernatsch and Peterson, 2018;Kurita et al., 2017;Lamers et al., 2020;Lanotte et al., 2018;Lazzaroni et al., 2019;Lee et al., 2012b;Li et al., 2013;Lim et al., 2015;Lotti et al., 2020;Luo and Yu, 2013;Muramatsu et al., 2013;Näf et al., 2018;Naruse et al., 2005;Natividad et al., 2019;Otten et al., 2018;Park and Cho, 2017;Sasaki and Takaiwa, 2014;Shin et al., 2019;Sylla et al., 2014a,b;Tiseni et al., 2019;Ulrey and Fathallah, 2013;Wehner et al., 2009;Wijegunawardana et al., 2019;Yong et al., 2017;Yu et al., 2019;Chen et al., 2018;Zhang et al., 2016), 66 evaluation studies (Abdoli-E et al., 2006;Abdoli-E and Stevenson, 2008;Abdoli-Eramaki et al., 2007;Alemi et al., 2019, 2019Bosch et al., 2016;Bridger et al., 2018;Daratany and Taveira, 2020;Frost et al., 2009;Gilotta et al., 2018;Godwin et al., 2009;Gorsic et al., 2020;Grazi et al., 2020;Huysamen et al., 2018b;Hyun et al., 2019Hyun et al., , 2020Ji et al., 2020;Kelson et al., 2019;Kim et al., 2020b,b,c;Kim and Nussbaum, 2019;Kinne et al., 2020;Ko et al., 2018;Koopman et al., 2019bKoopman et al., , 2020Kozinc et al., 2020a;Lamers et al., 2018;Lee and Chee, 2013;Lotz et al., 2009;Luger et al., 2019;Madinei et al., 2020a,b;Maurice et al., 2020;Miura et al., 2018b;Muramatsu et al., 2011;Pacifico et al., 2020;Picchiotti et al., 2019;Pillai et al., 2020;Pinho et al., 2020;Qu et al., 2021;Sadler et al., 2011;Schmalz et al., 2019;So et al., 2020;Spada et al., 2017Spada et al., , 2019Steinhilber et al., 2020;Theurel et al., 2018;Toxiri et al., 2018;Van Engelhoven et al., 2019;von Glinski et al., 2019;Wei et al., 2020a,b;Whitfield et al., 2014;Xiloyannis et al., 2019;Yin et al., 2019Yin et al., , 2020Yong et al., 2019;Zhu et al., 2018;Poliero et al., 2020;Tan et al., 2019) and 22 field studies (Amandels et al., 2019;Baltrusch et al., 2021;Claramunt et al., 2019;De Bock et al., 2021;de Vries et al., 2021;Dewi and Komatsuzaki, 2018;Ferreira et al., 2020;Gillette and Stephenson, 2018;Gillette and Stephenson, 2019;Graham et al., 2009;Hefferle et al., 2020;Hensel and Keil, 2019;Iranzo et al., 2020;Miura et al., 2018b;Motmans et al., 2019;Moyon et al., 2018;Omoniyi et al., 2020;Settembre et al., 2020;Smets, 2019;Spada et al., 2018;Thamsuwan et al., 2020;Wang et al., 2021). ...
... During the assembly tasks, the working height was adjusted to anatomic landmarks, i.e. trochantor major, knee and ankle height. Thirty-three back exoskeleton evaluations used a dynamic isolated lifting task (Abdoli-E et al., 2006;Abdoli-E and Stevenson, 2008;Abdoli-Eramaki et al., 2007;Alemi et al., 2019;Alemi et al., 2020;Baltrusch et al., 2019;Baltrusch et al., 2020a;Frost et al., 2009;Godwin et al., 2009;Gorsic et al., 2020;Huysamen et al., 2018c;Hyun et al., 2020;Ji et al., 2020;Kinne et al., 2020;Ko et al., 2018;Koopman et al., 2019b;Koopman et al., 2020;Kozinc et al., 2020a;Lamers et al., 2018;Lotz et al., 2009;Madinei et al., 2020a;Miura et al., 2018b;Picchiotti et al., 2019;Poliero et al., 2020;Qu et al., 2021;Sadler et al., 2011;Tan et al., 2019;Toxiri et al., 2018;von Glinski et al., 2019;Wei et al., 2020a;Whitfield et al., 2014;Yin et al., 2019;Yong et al., 2019). Twenty-one evaluation protocols encompassed a symmetric free lifting task (Abdoli-E and Stevenson, 2008;Abdoli-Eramaki et al., 2007;Alemi et al., 2019;Alemi et al., 2020;Baltrusch et al., 2019;Baltrusch et al., 2020a;Frost et al., 2009;Godwin et al., 2009;Gorsic et al., 2020;Huysamen et al., 2018c;Koopman et al., 2019b;Koopman et al., 2020;Kozinc et al., 2020a;Lamers et al., 2018;Lotz et al., 2009;Picchiotti et al., 2019;Poliero et al., 2020;Qu et al., 2021;Sadler et al., 2011;von Glinski et al., 2019;Wei et al., 2020a;Whitfield et al., 2014;Yin et al., 2019). ...
... Alemi et al. (2020) also investigated symmetric and asymmetric kneeled lifting. Fifteen studies included stoop lifting (Abdoli-E et al., 2006;Abdoli-Eramaki et al., 2007;Abdoli-Eramaki et al., 2007;Alemi et al., 2019;Frost et al., 2009;Hyun et al., 2020;Ji et al., 2020;Ko et al., 2018;Koopman et al., 2019b;Koopman et al., 2020;Kozinc et al., 2020a;Miura et al., 2018b;Tan et al., 2019;Toxiri et al., 2018;Yong Fig. 4. The distribution of the exoskeleton assessment types was illustrated across different exoskeletons. Back, shoulder and other exoskeletons were distinguished. ...
Objectives
To provide an overview of protocols assessing the effect of occupational exoskeletons on users and to formulate recommendations towards a literature-based assessment framework to benchmark the effect of occupational exoskeletons on the user.
Methods
PubMed (MEDLINE), Web of Science database and Scopus were searched (March 2, 2021). Studies were included if they investigated the effect of one or more occupational exoskeletons on the user.
Results
In total, 139 eligible studies were identified, encompassing 33, 25 and 18 unique back, shoulder and other exoskeletons, respectively. Device validation was most frequently conducted using controlled tasks while collecting muscle activity and biomechanical data. As the exoskeleton concept matures, tasks became more applied and the experimental design more representative. With that change towards realistic testing environments came a trade-off with experimental control, and user experience data became more valuable.
Discussion
This evidence mapping systematic review reveals that the assessment of occupational exoskeletons is a dynamic process, and provides literature-based assessment recommendations. The homogeneity and repeatability of future exoskeleton assessment experiments will increase following these recommendations. The current review recognises the value of variability in evaluation protocols in order to obtain an overall overview of the effect of exoskeletons on the users, but the presented framework strives to facilitate benchmarking the effect of occupational exoskeletons on the users across this variety of assessment protocols.
... To amplify human endurance while carrying heavy loads, BLEEX [13] (7-DOF/limb) was developed with intelligent and adaptable robot-based strategies where linear hydraulic actuators were used for the actuation of 4-DOF. Recently, Ji et al. [14] introduced a wearable exoskeleton, SIAT-WEXv2, to support the user's waist and bones while lifting heavy objects in construction and logistic industries by providing an assistive output of 28 N. ...
The design of an accurate control scheme for a lower limb exoskeleton system has few challenges due to the uncertain dynamics and the unintended subject’s reflexes during gait rehabilitation. In this work, a robust linear quadratic regulator- (LQR-) based neural-fuzzy (NF) control scheme is proposed to address the effect of payload uncertainties and external disturbances during passive-assist gait training. Initially, the Euler-Lagrange principle-based nonlinear dynamic relations are established for the coupled system. The input-output feedback linearization approach is used to transform the nonlinear relations into a linearized state-space form. The architecture of the adaptive neuro-fuzzy inference system (ANFIS) and used membership function are briefly explained. While varying mass parameters up to 20%, three robust neural-fuzzy datasets are formulated offline with the joint error vector and LQR control input. Thereafter, to deal with external interferences, an error dynamics with a disturbance estimator is presented using an online adaptation of the firing strength matrix. The Lyapunov theory is carried out to ensure the asymptotic stability of the coupled human-exoskeleton system in view of the proposed controller. The gait tracking results for the proposed control scheme (RLQR-NF) are presented and compared with the exponential reaching law-based sliding mode (ERL-SM) controller. Furthermore, to investigate the robustness of the proposed control over LQR control, a comparative performance analysis is presented for two cases of parametric uncertainties and external disturbances. The first case considers the 20% raise in mass values with a trigonometric form of disturbances, and the second case includes the effect of the 30% increment in mass values with a random form of disturbances. The simulation runs have shown the promising gait tracking aspects of the designed controller for passive-assist gait training.
... Previous studies have shown that exoskeletons have positive results in the biomechanical evaluation. It has been proven to significantly reduce the muscle activity of the main muscles involved in handling or overhead work [27,28]. The passive back exoskeleton has been shown to reduce spinal muscle activity by 20 to 25% in real car assembly operations [29]. ...
... In addition, the number of subjects in this study is the same as those in references [5,27] and higher than those in some previous researches such as [28,30], but more subjects, including female subjects, should be involved in the experiment in order to obtain more reliable results in the future. ...
The exoskeleton as functional wearable equipment has been increasingly used in working environments. However, the effects of wearing an exoskeleton on human thermal responses are still unknown. In this study, 10 male package handlers were exposed to 10 °C (COLD) and 25 °C (TEMP) ambient temperatures while performing a 10 kg lifting task (LIFTING) and sedentary (REST) both with (EXO) and without the exoskeleton (WEXO). Thermal responses, including the metabolic rate and mean skin temperature (MST), were continuously measured. Thermal comfort, thermal sensation and sweat feeling were also recorded. For LIFTING, metabolic heat production is significant decrease with the exoskeleton support. The MST and thermal sensation significantly increase when wearing the exoskeleton, but thermal discomfort and sweating are only aggravated in TEMP. For REST, MST and thermal sensation are also increased by the exoskeleton, and there is no significant difference in the metabolic rate between EXO and WEXO. The thermal comfort is significantly improved by wearing the exoskeleton only in COLD. The results suggest that the passive exoskeleton increases the local clothing insulation, and the way of wearing reduces the “pumping effect”, which makes a difference in the thermal response between COLD and TEMP. Designers need to develop appropriate usage strategies according to the operative temperature.
