Most individuals who experience a stroke exhibit several sensorimotor impairments that limit their independence in everyday activities. Hemiparetic gait is frequently characterized by reduced knee flexion in swing due to knee stiffness or muscle weakness and knee hyperextension or knee buckling in the stance phase. Recently, unilateral-powered orthoses have been designed to overcome the limitations of the passive knee-ankle-foot orthoses. This study presents a unilateral active knee orthosis exoskeleton, AKO-beta, endowed with a series-elastic actuator and designed to assist the knee in flexion and extension movements. In this article, we describe the system mechatronic design and its characterization on the bench, the control system, and pilot experiments with three poststroke participants. The device has a weight of 1.78 kg on the user's leg, with a lateral encumbrance of 76 mm. The pilot experiments aimed to verify the effects of the exoskeleton assistance in hemiparetic gait patterns. When walking with the device, participants on average increased the knee flexion on the paretic side by 18.70 degrees (+44.9%) during swing and decreased knee hyperextension in stance by 4.50 degrees, compared to walking without it. Overall, when walking with the exoskeleton, subjects showed an improved gait variable score of the paretic knee profile by 37.5% compared to walking without it. The temporal and spatial gait symmetry indices did not show clear changes, although an improvement in symmetry was observed in two of the three participants. These preliminary results suggest the potential benefits of the unilateral active knee orthosis exoskeleton to enhance and restore mobility in individuals with hemiparetic gait.

The assessment of gait parameters in daily life offers valuable insights for tailoring rehabilitation protocols and personalizing lower limb assistive devices. Integrating sensory systems into prostheses may enable adaptive control and continuous gait monitoring. Traditional assessment methods such as motion capture, force platforms (FPs), and wearable inertial measurement units (IMUs) are effective but often lack seamless integration with prostheses, limiting their use in everyday environments. This article presents a novel plantar sensory system designed for integration with lower limb prostheses. The system employs optoelectronic plantar pressure sensors embedded between the prosthetic foot and cosmetic cover at load-bearing regions of the gait cycle. Endurance testing confirmed its robustness over prolonged use. Ten healthy subjects participated in a study evaluating the system's ability to estimate vertical ground reaction force (vGRF) during walking. A Gaussian process regressor (GPR) was trained on sensory signals with force plate data as ground truth. Using leave-one-subject-out (LOSO) cross-validation, the model showed good generalizability (R-2 = 0.94 +/- 0.04), high correlation with FP data [Pearson r = 0.94 (0.05)], and comparable peak vGRF values. Model stability was assessed by repeating the training 30 & times;, yielding a coefficient of variation of the RMSE equal to 7.7%. The trained model was also applied to unseen data from two subjects with transtibial amputation, producing physiologically consistent vGRF profiles. The system also promptly detected gait events, identifying heel strike (HS) and toe-off with median delays of 0.01 and 0.002 s, respectively. These results support the potential of the system for gait parameter estimation in prosthetic applications.

Upper‐limb exoskeletons reduce overuse injuries in overhead work, but effectiveness depends on aligning assistance with biomechanics and user’s physical state. Most controllers rely on joint kinematics and task phase estimation, rarely accounting for fatigue from demanding tasks such as handling heavy handheld tools. This study presents fatigue‐driven assistance algorithm for a semi‐active upper‐limb occupational exoskeleton (OE). Fatigue is estimated in real time via electromyography (EMG) and heart rate (HR); median EMG frequency and averaged HR feed a linear regression controller that updates assistance according to physiological demand. Three conditions are evaluated: no exoskeleton, fixed assistance, and fatigue‐driven adaptive assistance, using muscle activation, HR, respiratory quotient (RQ), work duration, and perceived exertion as metrics. Adaptive assistance increases task duration by 41.2% ( p = 6.9 × 10 −4 ) versus no exoskeleton and reduces EMG activity in the anterior deltoid (AD) (26.5%, p = 0.002), posterior deltoid (23%, p = 0.02), upper trapezius (UT) (39%, p = 0.01), and medial deltoid (27%, p = 0.06). Fixed assistance yields smaller, nonsignificant duration increase of 9.9% ( p = 0.75), reducing AD by 16% ( p = 0.06) and UT by 27% ( p = 0.05). Both conditions reduce HR and RQ. Overall, results support fatigue‐driven control strategies for OEs.

Conventional gel electrodes are the gold standard for surface electromyography (sEMG), yet their bulkiness, stiffness, and limited gel lifetime prevents seamless day-long integration with wearable robots. We integrated ultrathin skin-conformal temporary tattoo electrodes with a powered unilateral hip exoskeleton and compared signal quality during treadmill walking against gel. In this pilot study, five healthy participants completed three consecutive walking blocks at fixed speed: (1) using gel electrodes; (2) using tattoo electrodes to compare signal quality; and (3) using the same tattoo electrodes (not repositioned) after eight hours of wear to simulate a full day of typical device use and to evaluate potential degradation in signal quality over time. Electrodes were positioned on muscles not covered by the exoskeleton interface (tibialis anterior and gastrocnemius medialis), as well as on muscles located beneath the exoskeleton cuff, which were potentially subject to motion artifacts due to the application of external forces by the exoskeleton (rectus femoris and biceps femoris, BF). Across all muscles, for both gel and tattoo electrodes, the root mean square error (RMSE) between normalized sEMG envelopes and biological activation profile was 0.069 ± 0.048, and Pearson’s correlation coefficient (ρ) was 0.844 ± 0.091. Re-testing the same tattoo electrode pair after eight hours confirmed day-long stability without the need for recalibration. Statistical analysis revealed no significant differences in signal quality, also when applying assistive forces, between the two electrode types and across all muscles (RMSE, all p ≥ 0.3125; ρ, all p ≥ 0.1250), as well as no degradation after eight hours (RMSE and ρ: all p ≥ 0.0626, uncorrected). Finally, in a proof-of-concept session, BF activity measured with tattoo electrodes was found reliable to drive hip-extension assistance in real time. Collectively, these results show that tattoo electrodes deliver signal quality comparable to gel electrodes while offering a low-profile skin-conformal interface and day-long usability, making them a promising option for enhancing EMG-based control in wearable robots.

This study explores the use of an upper-limb wearable exoskeleton for teaching violin technique to novices through haptic-assisted training. The educational potential of this technology was evaluated using a framework that integrated quantitative kinematic metrics and qualitative assessments, comparing a group receiving haptic feedback (N = 12) with a control group that did not (N = 12) in a mixed between-within-subjects design. Results from a double-blind expert panel indicated that participants trained with the exoskeleton outperformed the control group during recall measurements. In addition, spatial and spatiotemporal - but not temporal - kinematic metrics related to bowing technique improved significantly during training, with gains persisting during recall, and these outcomes were supported by self-reported user assessments. However, subtle features of the technology also became apparent, including interference with natural shoulder movements, exposing areas for refinement. In conclusion, this study suggests that haptic-assisted training with an exoskeleton can enhance specific motor skills in violin playing, highlighting promising directions for future research in educational technology and providing a quantitative framework for assessing motor skill development in haptic-assisted learning, which can further support the development and validation of educational technologies. However, given the absence of long-term retention measurements and the limited generalizability associated with the small sample size, the findings of this pilot study should be interpreted with caution.

Synchrony is a cornerstone for the successful physical interaction between humans while cooperating or competing towards a goal and is achieved by correct and smooth information exchange between subjects. Recently, Human-Robot-Human (HRH) interaction arose as an emerging paradigm for improving motor control in collaborative and dyadic motor tasks. Among the robotic solutions explored for agent coupling, exoskeletons are powerful tools for exerting torque and force feedback at the joint level. In this work, two identical torque-controlled elbow exoskeletons were used in dyadic interaction, to provide haptic feedback and improve synchrony between two individuals performing a tapping task. Each exoskeleton is lightweight and compact, weighing 0.8 kg on the arm. Bench tests to verify the performance of closed-loop torque control showed a residual torque below 0.2 Nm when the reference torque was set to zero, and a bandwidth higher than 6 Hz, thus achieving adequate performance for applications in HRH scenarios. In human subjects' experiments, the root-mean-squared error between the two users' joint trajectories was 50% lower when users received haptic feedback compared to the condition without feedback; the relative phase error was lower than 60%. The results of this study suggest that exoskeletons can enhance synchrony in HRH interactions, being potentially useful in rehabilitation training, collaborative industrial tasks or sport and music learning.

Work-related musculoskeletal disorders significantly impact healthcare professionals during patient-handling tasks. This work presents the results of a study that evaluated a spring-loaded lumbar exoskeleton, called SAFE-T, in reducing the physical strain for caregivers. Fifteen healthcare professionals performed patient transfer and bed repositioning tasks in three conditions, without wearing the SATE-T and with SAFE-T using two different levels of assistance. A healthy volunteer simulated a partially collaborative patient. The effect of the exoskeleton was assessed through superficial electromyographic measurements, movement kinematics, and perceived exertion. Results showed that the exoskeleton significantly reduced muscle activation across back muscles, with both assistance levels demonstrating the effectiveness of this study. Specifically, muscle activity was significantly reduced in the right lumbar erector spinae (19-29%), thoracic erector spinae (10-21%), and left erector spinae iliocostal (23-29%) muscles. The global Rated Perceived Exertion scores decreased significantly in both tasks when using the SAFE-T (p < 0.05). These findings highlight the potential of this device to reduce physical strain and potentially mitigate the occurrence of work-related disorders in healthcare professionals.

Joint actions among humans rely on the integration of multiple sensory modalities, most notably auditory and visual cues, which support explicit communication between partners. However, haptic feedback provides a direct, implicit channel for sensorimotor communication, and its contribution to fine motor coordination in joint actions remains largely unexplored. Here, we demonstrate that haptic communication, rendered through bidirectionally coupled wearable robots, outperforms traditional auditory-visual feedback in a complex and challenging real-life joint action: ensemble violin performance. First, we developed a pair of two-degree-of-freedom upper-limb exoskeletons capable of transparently following violinists' natural movements and rendering viscoelastic torques proportional to the joint angular deviation between the partners. Then, we designed a within-subject experiment with 20 violin duos performing a musical piece under four sensory feedback conditions: auditory (A), auditory-visual (AV), auditory-haptic (AH), and auditory-visual-haptic (AVH), across two tempi (72 and 100 beats per minute). Despite the musicians being unfamiliar with the robot-mediated haptic feedback and unaware of the bidirectional connection between them, haptic feedback (AH and AVH) substantially enhanced spatiotemporal coordination and dynamic musical alignment compared with the extensively trained auditory-visual feedback (A and AV). The multisensory feedback condition AVH yielded the highest scores across all measures. Our findings demonstrate that haptic feedback can support fine motor coordination in violin duo performance more effectively than visual cues, particularly for professional musicians, because of its implicit and embodied nature, and that it can be effectively delivered via wearable robots, expanding the paradigms of human-human sensorimotor interactions.

This workshop aims to develop a roadmap for understanding the impact of robotics on human employment within the context of Industry 5.0. It explores key factors in this transition, including the risks and benefits of digital automation, ethical considerations regarding worker skills and well-being, and protective measures for workers and consumers. Focusing on the theme of sociocultural risks, the workshop aims to reflect on traditional notions of work, productivity, and the value of human labor in the era of advancing robotics and automation. It challenges the concept of labor devaluation, assesses its impact on worker recognition and efficiency, and questions meritocratic paradigms. To facilitate interdisciplinary dialogue, the workshop engages philosophers and engineers in addressing ethical dilemmas in technology development. It explores the social significance of human effort and movement when interacting with autonomous robots and occupational exoskeletons. By examining these technologies’ adaptability and role in human-machine interaction, especially in workplaces, the workshop intends to contribute to discussions on technological advances and their societal implications.

This work introduces a controller for an upperlimb rehabilitative exoskeleton based on reservoir computing (RC). The controller decodes the motor intention of the user by observing the electromyographic (EMG) activity of four upperlimb muscles and end effector (EE) kinematics and then assists the movements of upper-limb during the execution of planar reaching tasks. After tuning the hyperparameters of the RC, the controller was tested by three healthy participants wearing a shoulder-elbow active exoskeleton. The controller predicted the direction of reaching movements across eight possible targets positioned on a 25 cm circumference, achieving an average accuracy of $\mathbf{7 4. 1 2 \%}$. Given the geometric structure of the task, we introduced a macro-direction measure of goodness (MDG) metric that considered both correct predictions and those corresponding to targets adjacent to the true one, resulting in an average performance of 96.63 %. Moreover, RC-ID outperformed a kinematics-only benchmark before kinematic onset and surpassed an EMG-only benchmark during the later phases of the reaching movement execution. Finally, effects of assistance were assessed by evaluating the variation of muscular activation during exoskeleton-assisted movements, which led to reductions up to $-47.4 \%$ with respect the activations during unassisted movements.

Despite numerous laboratory studies, assessments of occupational exoskeletons (OEs) with experienced workers remain limited in the state of the art. This work presents a study conducted in the port operations of containers and goods load and unload inside cargo ships, to investigate the effectiveness of two OEs. Such operations are manually demanding and can increase the physical burden of port operators, which may result in the development of work-related musculoskeletal diseases. Two commercially-available passive OEs were tested, an upper-limb and a lower-back exoskeleton. Electromyography (EMG) data and subjective perceptions of effort were collected. Results show significant reductions in EMG activity for both exoskeletons, particularly in shoulder and trunk muscles. The results of the questionnaires indicated a good perceived usability and acceptance of the devices. This study demonstrates the potential effectiveness of passive OEs in reducing physical strain in port operations. Results align with findings in other work contexts.

Millions of individuals surviving a stroke have lifelong gait impairments that reduce their personal independence and quality of life. Reduced walking speed is one of the major problems limiting community mobility and reintegration. Previous studies have shown positive effect of robot-assisted gait training utilizing hip exoskeletons for individuals with gait impairments due to a stroke, leading to increased walking speed in post-treatment compared to pre-treatment assessments. However, no evidence emerged of a significant increasing in walking speed attributable to device usage compared to walking without the device. In this pilot investigation, we observed that hip flexion/extension assistance delivered by a portable bilateral powered hip exoskeleton increased overground self-selected walking speed by 20.2 ± 5.0% on average among six chronic post-stroke survivors. When comparing walking with and without the hip exoskeleton within the same experimental session, the observed speed increment resulted in statistically and clinically meaningful improvement (0.14 ± 0.03 m/s > minimal clinically important difference, p = 0.015). The increased walking speed was the result of a higher self-selected cadence and longer step length both on the paretic and nonparetic limbs. By facilitating gait, a bilateral hip exoskeleton could be a viable technology for extending locomotor mobility and facilitating gait training of individuals affected by post-stroke hemiparesis.

Upper-limb occupational exoskeletons reduce injuries during overhead work. Previous studies focused on muscle activation with and without exoskeletons, but their impact on shoulder fatigue remains unclear. Additionally, no studies have explored how exoskeleton support levels affect fatigue. This study investigates the effects of assistive profiles on muscular and cardiovascular fatigue. Electromyographic (EMG) and electrocardiographic signals were collected to compute EMG median frequency (MDF), heart rate (HR), and heart rate variability (HRV). Fatigue was assessed using three MDF and HR metrics: relative change ( $ {\mathrm{MDF}}_{\Delta } $ , $ {\mathrm{HR}}_{\Delta } $ ), slope ( $ {\mathrm{MDF}}_{\mathrm{slope}} $ , $ \mathrm{H}{\mathrm{R}}_{\mathrm{slope}} $ ), and intercept ( $ {\mathrm{MDF}}_{\mathrm{intercept}} $ , $ \mathrm{H}{\mathrm{R}}_{\mathrm{intercept}} $ ) of the linear regression. Results showed $ {\mathrm{MDF}}_{\Delta } $ decreased 64% (p = 0.0020) with higher assistance compared to no exoskeleton; $ {\mathrm{HR}}_{\Delta } $ decreased 40% (p < 0.0273) with lower assistance, $ {\mathrm{MDF}}_{\mathrm{slope}} $ decreased up to 67% (p = 0.0039) and $ \mathrm{H}{\mathrm{R}}_{\mathrm{slope}} $ by 43% (p < 0.0098) with higher and medium assistance. HRV metrics included root mean square of successive differences (RMSSD) and low-frequency to high-frequency power ratio (LF/HF). RMSSD indicated parasympathetic dominance, while rising LF/HF ratio suggested physiological strain. Findings support occupational exoskeletons as ergonomic tools for reducing fatigue.

Occupational exoskeletons have the potential to prevent work-related musculoskeletal disorders. Their widespread adoption should be promoted by investigating their long-term innocuity, sustained effectiveness, and practicability. This article presents a six-months longitudinal study exploring effects of an arm support exoskeleton (ASE) on six male workers, examining potential side effects, ASE's effectiveness, and its integration into daily work practices. Monthly clinical visits were scheduled to monitor workers’ health. Effectiveness, usability and acceptance metrics were collected at the beginning of the study and after six months. No side effects were found in clinical metrics during the study. Significant reductions, consistent overtime, were observed in shoulder muscle activity (up to 30%) and in effort perception-related metrics (up to 2.4 out of 10 points). Usage time settled around 10% of the monthly work-shift and gradually decreased possibly due to external factors (e.g., social, motivational, and seasonal factors) beyond researchers' control. Results encourage the continuation of similar investigations to strengthen these findings and promote the use of occupational exoskeletons.

This paper presents the design and characterization of a robotic ankle-foot prosthesis embedding torsional series and parallel elasticity to mimic the biomechanics of a healthy ankle during prototypical tasks. The prosthesis components were selected to satisfy biomechanical requirements in different locomotion modes. Benchtop testing showed an open-loop current-to-torque bandwidth of 12 Hz, position tracking errors lower than 1.6 deg and torque step response overshoot below 3%. While tracking normative position trajectories, the parallel spring generated approximately the 25% of the peak biological torque during the dorsiflexion phase of walking, hence reducing the motor's work. Moreover, the actuation unit can mimic a broad range of virtual impedances similar to the one of the intact ankle. The results of bench testing demonstrated that the device is versatile and could be further tested in human-subjects testing.

Hand injuries have a considerable impact on daily life, requiring extensive rehabilitation efforts in both clinical and home environments. Portable wearable devices show promise in addressing this need., rendering rehabilitation repeatable., measurable., and challenging at the same time. This paper presents a novel hand exoskeleton designed to assist the thumb and index metacarpophalangeal (MCP) joints in flexion- extension movements while keeping the thumb free or locked in adduction-abduction and circumduction movements. The actuation units are based on a series-elastic architecture (SEA). Transmission chains include self-aligning mechanisms to avoid undesired parasitic forces on the user's musculoskeletal system. The device has a total weight of 190 g and can exert a maximum torque at the MCP joint up to 0.9 Nm. The lockable thumb chain enables users to lock the thumb in various configurations while assisting the flexion/extension motion. The device has been tested on the bench in position and admittance control., and with a human subject using electromyography-triggered flexion/extension movements. Results show a root mean square error in position control below 0.5 deg in all experimental conditions. The results prove that the developed hand exoskeleton can be used in rehabilitation applications.

BackgroundIn the context of post-traumatic hand rehabilitation, stiffness of the hand joints limits the range of motion (ROM), grip strength, and the possibility of performing simple grasps. Robotic rehabilitation has been widely adopted for hand treatment with neurological patients, but its application in the orthopaedic scenario remains limited. In this paper, a pilot study targeting this population is presented, where the rehabilitation is performed using a powered finger exoskeleton, namely I-Phlex. The device aims to mobilize the metacarpal-phalangeal joint (MCP) in flexion-extension movements. The objective of the study was to verify the short-term efficacy, experience of use, and safety of I-Phlex in a clinical setting. As a secondary objective, the study verified the device's capability to measure clinically relevant variables.MethodsSix subjects with trauma-related illnesses of the right hand took part in the experiment. Passive and active range of motion (PROM and AROM) were recorded at the beginning and the end of the session by the therapist and by the exoskeleton. Experience of use was assessed through ad-hoc questionnaires and a numerical pain rate scale (NPRS). Safety was assessed by computing the number of adverse events during the operation.ResultsMedian increases in the PROM and AROM of 5.88% and 11.11% respectively were recorded among subjects. The questionnaires reported a median score of 93.83; IQR (85.01-100) and 80.00; IQR (79.79-93.75) respectively. No increase in the median NPRS was recorded among subjects between pre-and post-treatment. No major adverse event or injury to the patients was recorded. Only one malfunction was reported due to the brake of a transmission cable, but the patient reported no injury or discomfort. No statistical significance was observed between the ROM measurement recorded using the exoskeleton and the ones taken by the therapist using the goniometer.ConclusionsThe device and related rehabilitation exercises can be successfully used in the clinical rehabilitation of the MCP joint. The device measurements are in line with the goniometer assessment from the therapist. Future studies will aim to reinforce the results obtained, introducing a control group to conclude on the specific contribution of the technology compared to conventional therapy.Trial registrationHand Motor Rehabilitation Using a Wearable Robotic Device (WRL HX MCP), Clinicaltrials.gov ID NCT05155670, Registration date 13 December 2021, URL https://clinicaltrials.gov/ct2/show/NCT05155670.

Lower limb prosthetics, essential for restoring mobility in individuals with limb loss, have witnessed significant advancements in recent years. This systematic review reports the recent research advancements in the field of semi-active and active lower-limb prostheses. The review focuses on the mechatronic features of the devices, the sensing and control strategies, and the performance verification with end-users. A total of 53 prosthetic prototypes were identified and analyzed, including 16 knee-ankle prostheses, 18 knee prostheses, and 19 ankle prostheses. The review highlights some of the open challenges in the field of prosthetic research.

Reducing energy consumption during walking is a critical goal for transtibial amputees. The study presents the evaluation of a semi-active prosthesis with five transtibial amputees. The prosthesis has a low-power actuator integrated in parallel into an energy-storing-and-releasing foot. The actuator is controlled to compress the foot during the stance phase, supplementing the natural compression due to the user’s dynamic interaction with the ground, particularly during the ankle dorsiflexion phase, and to release the energy stored in the foot during the push-off phase, to enhance propulsion. The control strategy is adaptive to the user’s gait patterns and speed. The clinical protocol to evaluate the system included treadmill and overground walking tasks. The results showed that walking with the semi-active prosthesis reduced the Physiological Cost Index of transtibial amputees by up to 16% compared to walking using the subjects’ proprietary prosthesis. No significant alterations were observed in the spatiotemporal gait parameters of the participants, indicating the module’s compatibility with users’ natural walking patterns. These findings highlight the potential of the mechatronic actuator in effectively reducing energy expenditure during walking for transtibial amputees. The proposed prosthesis may bring a positive impact on the quality of life, mobility, and functional performance of individuals with transtibial amputation.