Wearable Robotics: Challenges and Trends

Human intention decoding is a primary requirement to control an exoskeleton. In this work, a new method of decoding human intention by Forcemyography (FMG) is explored to estimate elbow joint angle during arm motion. The method utilizes an FSR-based sensor band to read muscle contraction and relaxation. The readings of the sensor band are mapped to the desired joint angle by using coarse Gaussian support vector machine (SVM) regression algorithm. The estimated joint angle is further used to control an elbow joint exoskeleton. Results show that the new method is able to estimate reliably the joint angle for controlling the exoskeleton.

Wearable tactile sensors are significant in biomedical robotic applications where force feedback is important. In this work, a soft tactile sensor is proposed for force localization. The tactile sensor was manufactured by using layer-by-layer technique that enables flexibility. The sensor has 9 lead zirconate titanate (PZT) elements placed in 3 × 3 matrix form which are 4 × 4 mm2 and the spatial resolution is 3 mm. The voltage values gathered from the sensor were conditioned by a charge amplifier circuit. A human inspired machine learning procedure called Neural Networks was used for force localization. The success rates with respect to different network structures were presented and the maximum success was realized as 80.71%.

We present the development of an innovative stretchable tactile sensor based on electrical impedance tomography (EIT) for applications in wearable robotics and rehabilitation. To extract the tactile information we exploit the electrical impedance tomography technique to reconstruct the local conductivity changes of a piezoresistive fabric. The EIT method poses several new challenges in the reconstruction, counterbalanced by the overcoming of many of the drawbacks of the current tactile sensors. Results obtained are preliminary but encouraging and we believe that the combination of the EIT method with advanced machine learning techniques will enable reliable wearable tactile sensing.

Employing six-bar linkages for knee orthoses is an advantageous choice in many ways. In relation to four-bar linkages the six-bar linkage tracks more accurately the natural ankle trajectory and provides more flexibility in the design for stability. Additionally, the 1-DOF mobility of linkages alongside the available moment leverage offers advantages in cost-effectiveness over open-kinematic-chain designs.This work presents the analysis as well as the design and optimization considerations of a knee orthosis that is based on a Watt’s six-bar linkage. The main aim is to lay the foundations for analytical design and development of a knee orthosis that is cost-effective, self-cancelling and optimized for passive-active energy exchange as well as energy harvesting and return.

With the objective of satisfying the technical and functional requirements set for intention detection (ID) algorithm, we investigated suitable strategies to reduce the number of remote units such as inertial measurement units (IMU). The optimization should not affect the ID algorithm, which needs to detect continuous transitions between different locomotion modes such as ground-level walking, walking up and down slopes, climbing/descending stairs, standing up, sitting down, turning and other scenarios of real life. In the developed solution, the number of remote units was reduced from 9 to 4. In order to achieve the same level of ID algorithm performance, the WSA units need to perform almost perfectly. The main innovation is nearly perfect data transfer from remote units to the master unit. This way a package loss below 0.05% of transferred packages is achieved.

Thimble/glove-based wearable systems are opportunistically placed on fingertips/hands and enable haptic devices, robotic/prosthetic hands to gather valuable information about physical interaction with the environment in an easy way. In particular, incipient slip detection and force acquisition are two important phenomena for human/robotic fingertips to successfully manipulate the real or virtual objects. In this study, a wearable fingertip tactile sensor (WeFiTS) capable of sensing incipient slippage and force variation in various directions to enhance interaction and manipulation while performing tasks is proposed. The fundamental design criteria of WeFiTS are also evaluated with FEA feasibility analysis and experimental evaluation.

The rapid growth of wearable robots in the last decade requires tackling practical issues that arise from their daily use, among which comfort is of great importance. In this work we quantify the level of comfort of a soft exosuit for the elbow by measuring the distribution of pressures at its interface with the human body. We do so with five different cushioning materials, commonly used in sport equipment and orthoses, and identify the ones exhibiting lower peaks of pressure. Polyethylene sponge and neoprene result in the best padding.

Wearable robots enhance the ability of their wearers to physically interact with the world, and can benefit rehabilitation efficiency, assistive devices’ effectiveness, and ergonomic support of workers. Wearable robots’ ergonomics and safety can be promoted by using actuators made of soft materials, but soft actuators in the literature are unable to produce the high torques required for lower limb activities of daily living (ADLs), for example, extension of the knee for sit-to-stand.This paper presents and validates a method for realizing a soft high torque actuator, the pleated pneumatic interference actuator, for knee extension. It was shown to produce a torque of 150 Nm at 2 bar and an angle of 70°. Future work will see the development of a portable pressure source to inflate the wearable actuator.

The objective of this research was to apply a user-centered design approach to the development of a soft exoskeleton for lower limb assistance. There has been a clear shift from hard to soft robotic exoskeletons in recent years. Soft exoskeleton technologies typically comprise sensors and actuators embedded in fabric/technical textiles. This approach to physical assistance offers benefits in usability for wearers, but also presents challenges e.g. how the concepts are put on/off and worn for long durations considering the personal needs of the wearer. Presented is a structured three-cycle development approach which considers user-centered design principles, but also a participatory user-driven design-test-redesign methodology. Target users for the concept (older adults, individuals post-stroke or incomplete spinal cord injury) were involved in concurrent design evaluation and development throughout the design process.

Textile based technologies can generate solutions highly adaptable with wearable robots and devices. Textile jamming (TJ) is a stiffness modulating technique with elaborated textile materials. The fabric with embedded miniature and rigid segments remain flexible due to the textile substrate while they present a high variation of stiffness (up to 17 times) in their stiff mode. The resulted TJ packs can be assembled by traditional sewing technique to the textile garments.

In this work we describe the developments of soft mechanical sensing technologies for XoSoft, a soft lower-limb exoskeleton for assisting people with low to moderate levels or reduced mobility. Starting from the results obtained in integrating capacitive strain sensors in standalone knee and ankle modules, we embed the capacitance constituent electrodes directly in the garment fabric, still guaranteeing an electrically shielded design. Embroidery of conductive yarns with F-head and W-head were tested, varying several parameters, such as stitch length and distance, presser foot height, and geometry (zig-zag patterns). Based on these techniques, a novel sensorized kneepad was fabricated. The adopted solutions make the sensing system more robust, improve both wearability and user comfort, and are expected to allow long term monitoring of joint movements.

We have been on developing new approaches to design, manufacture, and control soft wearable robotic devices and characterizing their performance through biomechanical and physiological studies so as to further the scientific understanding of how humans interact with such machines. Example application areas include enhancing the mobility of healthy individuals such as soldiers walking with a heavy load, restoring the mobility of patients with gait deficits such as those poststroke, and assisting those with upper extremity weakness to perform activities of daily living such as patients with a spinal cord injury. This abstract summarizes recent results from evaluation of these devices in clinical populations.

The present study aims at designing and evaluating a low-cost, simple and portable system for human kinematics (joint angles) and kinetics (joint torques) motion assessment. The system is based on a single camera, a set of customized markers, low-cost inertial measurement units and an affordable Wii Balance board. The automatically detected and tracked marker positions and orientations were used synchronously with other sensors data as inputs to an Extended Kalman Filter based on a biomechanical model of the investigated tasks. The method was validated with arm motions and with lower-limb motions of a subject wearing an exoskeleton. External ground reaction forces measured with a Wii Balance board were compared to the estimated ones based on the proposed low-cost system. Comparative analysis shows good accuracy with a low average NRMS error.

This paper presents the development procedures of a high power series elastic actuator that can be used in torque-controlled exoskeleton applications as a high-fidelity torque source. In order to provide a high torque output while containing its weight, the main objective was to satisfy dimensional and weight requirements within a compact structure. A three-fold design approach was implemented: (i) The torsional spring was designed using finite element analyses and its stiffness profile was experimentally tested via a torsional test machine, (ii) thermal behavior of the actuator was experimentally examined to ensure sufficient heat dissipation, (iii) the fatigue life of the spring was computed to be 9.5 years. Having manufactured the actuator, preliminary torque-control experiments were conducted. As the result, a high-fidelity torque control was achieved with a control bandwidth of up to 12 Hz.

Impedance based control is an established strategy to provide assist-as-needed power support in rehabilitation. The studied control in this paper differs, however, from the standard approach. Instead of following a defined spatio-temporal motion where the assisting torques depends on the capacity of the user to follow a trajectory, the controller is divided in gait phases with constant impedance parameters. This approach should allow more freedom of the user and simple adaptability of assistance level to the user condition. The simulated gait pattern relies on three states (swing, stance and a double support phase) which are associated to different spring-like impedances. In this paper, we investigate the relation between the gait and parameters such as the spring stiffness and the attractive position. Results show that both the user and the impedance’s parameters can influence gait characteristics such as step length, cadence, walking velocity.

The impact of arm rehabilitation robots increases with their usability. Hereby, usability can refer to many aspects of the robot’s functionalities in relation to interaction with the patient and/or the therapist. In the current case, the usability of robotic hand modules are in the focus. Especially for patients with spastic hand function, the design of the hand module is a critical factor for the patient set-up time. In this paper, the development of a new hand module for the ARMin according to usability requirements is presented. The requirements entail fast set-up time, functional movement and force training as well as hygiene factors. The developed hand module fulfills the requirements and is expected to increase usability and acceptance of the device.

Lower limb exoskeletons are motorized and instrumented wearable devices rigidly interfaced with the wearer. Their roles are to assist walking or mobilize legs to make people walk.

We have developed an innovative admittance-controlled Balance Assessment Robot that enables movement of a pelvis in all six degrees-of-freedom while a subject is walking on an instrumented treadmill. Further, we have developed a number of training approaches that are targeted to diminish specific deficiencies like gait asymmetry, insufficient weight-bearing, reduced push-off and poor dynamic balancing capabilities. A novel approach of precisely-timed push-like exertion of forces to the pelvis, performed similarly to physiotherapists that physically manipulate pelvis to indirectly modify trajectories of pelvis and legs of trainees, was developed. The developed approach was implemented in a series of case studies involving high-functioning stroke subjects in the early chronic stage. The results of prolonged training with high volume, specificity and intensity brought about significant changes in the balancing capabilities as well as in overall walking performance.

Robot-assisted gait rehabilitation improves gait- and balance related outcome measures, but its merit over other gait rehabilitation methods is still insufficiently proven. The trunk and pelvis are important to maintain balance during gait. Despite, scarce research has been presented concerning the importance of the trunk and the pelvis in different types of gait rehabilitation methods. We investigated whether the amount of bodyweight support and the amount of guidance force have an influence on the movements of the trunk and the pelvis during robot-assisted walking (Lokomat-system). The results of this study suggest that walking with the Lokomat-system leads to significant changes in trunk and pelvis movements, which influence the training of the trunk balance during robot-assisted walking. These results should be taken into account in the development of gait rehabilitation robots and gait rehabilitation strategies.

Maintaining balance following gait perturbations is difficult and still not well addressed in gait assistive devices. A challenge is in identifying perturbations, and whether and which responses are required to reestablish balance and walking. Here, we investigate the timing of changes in the kinematic and muscle activation patterns of unimpaired subjects to external perturbations. We used the ETH Knee Perturbator to lock the knee at different points of swing phase, and identified changes in the gait pattern with Statistical Parametric Mapping, adjusted for data containing perturbations. We show that kinematic patterns differ within approximately 100 ms of the perturbation, and that muscle activity changes later, much closer to foot-strike. Our results suggest that mechanical (joint angles and velocities) sensors are best suited to identify external perturbations, devices should change their behavior in response to such perturbations, and responses may not need to be initiated immediately following the perturbation.

Sensory feedback systems can improve gait performance of lower-limb amputees by providing information about the foot-ground interaction force. This study presents a new platform designed to deliver bilateral vibrations on the waist of the user, synchronously with specific gait events. Preliminary perceptual tests were carried out on five healthy subjects to investigate the perception thresholds on the abdominal region. The reaction time and the percentage of correct perceptions were computed to compare three stimulation levels: 50%, 70% and 100% of the maximum vibration amplitude (i.e., 1.5 g, 1.9 g and 2.2 g). The reaction times decreased with higher activation levels. The percentage of correct perceptions was 40% with 50% stimulation level and higher than 97% with 70% and 100% stimulation levels, respectively. The results suggest that vibration amplitudes of 1.9 g provide vibrotactile stimulation that can be effectively perceived during walking, thus used to convey sensory information.

The quality of life of lower limb amputees strongly depends on the performance of their prosthesis. Active prostheses controlled by prosthesis sensors can participate to the movement and improve the walking performance of the amputees. However, a promising control mechanism involves the use of electromyography (EMG) to decode motor intentions. This approach could timely inform the prosthesis about the steps that the patient is going to perform much earlier compared to the feedback given by sensors. Here, we investigate whether an EMG-based algorithm is able to detect the motor intentions of transfemoral amputees. Subjects with a transfemoral amputation performed different motor tasks (e.g., ground level walking, climbing up/down stairs), while we recorded the EMG signals from surface electrodes placed on the subject’s stump. Our decoding algorithm achieved 100% motion intention discrimination. Such perfect decoding was achieved usually after less than 100 ms from the onset of the movement, thus ensuring that the information about the next step could be transmitted to the active prostheses with a sufficient advance to achieve its proper control. These results showed not only the feasibility of EMG-based online decoding of motor intentions, but also that perfect decoding can be achieved online with as little as one recording site, ensuring a minimum discomfort and encumbrance of the whole system.

Lower limb prosthesis performance determines the quality of life of amputee patients. Such performance will benefit from a feedback informing the patient about the gait phase and the overall condition of the foot. This study reports the design and validation of a wearable haptic feedback system conceived to assist lower-limb amputees in various locomotion scenarios. Three vibrating motors were attached to a belt in textile to provide information about the foot-ground contact, by remapping the variables detected under the foot, on the waist of the user. Multiple activation patterns were implemented and compared in a pilot study involving one able-bodied subject, during walking, ascending and descending stairs. A novel assessment protocol was proposed to benchmark the different stimulation patterns. The protocol resulted to be a viable method for quicker development and testing of new strategies.

COVR is a European project driven by five national research and technology organizations. Through the development of an intuitive toolkit and a range of testing protocols for validation of safety for robots sharing space with humans, it will increase the safety of all types of collaborative robots across all domains with special attention to rehabilitation robotics.

Powered exoskeleton can restore locomotion to spinal cord injury subjects but measuring their impact on the upper limbs is critical, since repeated excessive loads are strongly correlated to chronic pain at shoulder level.This paper presents a novel set of instrumented crutches, able to measure force exerted on the ground during walking sessions, thanks to embedded time-of-flight cameras and force sensors.The force sensors, along with an inertial module, assess the force acting on the upper limbs, while the time-of-flight cameras detects the gait phases looking at the feet position.The aim is to provide an affordable measuring system, without requiring a fully instrumented gait-lab, allowing the user-robot interaction to be measured in a more natural setting, closer to the foreseen working condition.The instrumented crutches are fully independent of any other instrumentation to allow a comparison of different exoskeleton models in terms of upper limb involvement.

In this paper preliminary results of the H2020 EUROBENCH project are reported. EUROBENCH aims at defining a unified benchmarking framework for bipedal robotics. In particular, in this paper the structure of the survey promoted by the EUROBENCH consortium and its initial results are briefly reported. Objective of the survey is addressing a comprehensive analysis of the priorities for bipedal walking robots from the stakeholders point of view (e.g. experts, end-users, etc.) both in the humanoids and in the wearable robotics fields.

Physical interfaces have an important role in achieving efficient, safe and comfortable transmission of forces between the exoskeleton and the human body. They are normally composed of different compliant elements disposed in series between the skin of the user and the exoskeleton frame. Modelling how the compliant properties of physical interface will affect the transmission of forces may be useful to improve the design process towards more effective, safe and user-specific exoskeletal devices. As a first step in this direction, we propose a simplified 2-dimensional model representing the interaction of a single-actuated-joint exoskeleton with the human limb through a compliant element. We studied the effects of stiffness value associated to the tissues in the behavior of the whole system with simulated results of the model.

Advances in wearable devices have led to an increased need to develop sophisticated and individualized control strategies. To address this problem, several researchers have begun exploring human-in-the-loop optimization methods that automatically adjust control parameters in a wearable device using real-time physiological measurements. A common physiological measurement, metabolic cost, poses significant experimental challenges due to its long measurement times and low signal-to-noise ratio. This study addresses the challenges by using Bayesian optimization—an algorithm well-suited to optimizing noisy performance signals with very limited data—to perform control adaptation online. When applied to a soft exosuit designed to provide hip assistance, optimized control parameters were found in 24 min with a significant reduction in metabolic cost. These results suggest that this method could have a practical impact on improving the performance of wearable robotic devices.

This paper reports a preliminary overview on the existing metrics and benchmarks for the assessment of lower limb wearable robotics performance. This analysis was conducted to identify the current necessities, preferences, and deficiencies on this topic within the scientific robotics community. Based on these results, we aim to establish a robust set design criteria of a comprehensive benchmarking scheme for wearable robotic technology considering real life scenarios.

This paper presents the instrumentation of a lower limb exoskeleton with polymer optical fiber (POF) sensors. The robotic device presents a potentiometer and an electronic strain gauge (ESG) for the assessment of angle and human-robot interaction forces, respectively. Such devices are compared with the proposed POF curvature sensor and a POF-based strain gauge (POF-SG). The results show a root mean squared error (RMSE) between the POF curvature sensor and the potentiometer of 1.80° in a measurement ranging from 10° to 80°, whereas a RMSE of 1.31 Nm was obtained between the ESG and POF-SG in a range of 0 to 14 Nm. Such results demonstrate the feasibility of POF sensors as alternative solution for the instrumentation of wearable robots.

The development and a preliminary evaluation of a new active ankle-foot orthosis for gait assistance called T-FLEX are presented in this paper. The purpose of this device is to support patients with locomotion disabilities during rehabilitation treatment of the ankle joint. This device is based on bio-inspired actuation, in which the stiffness can be adjusted according to a gait phase detection, thereby reproducing the behavior of antagonistic muscles. A preliminary trial with a healthy subject (kinematic analysis) reveals an increase in the range of motion in ankle kinematics, which is desirable for ankle rehabilitation and assistance.

Series Elastic Actuators (SEAs) are used extensively in the field of wearable robotics because of their energy efficiency. Redundant drivetrains enable a further reduction in electrical energy consumption, as they use the actuator’s motors in a more energy efficient way. In this work, we present a Series Elastic Dual-Motor Actuator (SEDMA), a kinematically redundant actuator with series elasticity. We simulate its use in an ankle prosthesis and compare its energy efficiency to that of a traditional SEA. Results indicate an energy reduction of 16% compared to the SEA.

On exoskeletons, physical interfaces with the body are one of the key enabling component to promote user acceptance, comfort and force transmission efficiency. A structured design workflow is needed for any application-driven product, such as industrial exoskeletons. In this paper, we review objective and subjective evaluation metrics that can be applied to physical interfaces. These indexes can be evaluated to create an ordered list of requirements to guide their future design. Pressure magnitude, duration, distribution, direction and time to don and doff are relevant objective indexes related to interfaces. Pain, comfort and ease of operation are subjective indexes. We propose that collecting a suitable set of metrics will lay the foundation for effective design guideline for industrial exoskeletons.

This paper deals with the design and evaluation of a modular exoskeleton for rehabilitation of lower limb movements. The exoskeleton is composed of lightweight tubular structures and six free joints that provide actuation and configuration modularity to the system. Experiments considering the interaction between a healthy subject and the exoskeleton are performed to evaluate the influence of the exoskeleton structure on kinematic and muscular activity profiles during walking. Also, an optimal impedance controller for exoskeletons was evaluated considering the modular exoskeleton.

This paper presents the design and preliminary testing of a full-body assistive exoskeleton AXO-SUIT for older adults. AXO-SUIT is a system of modular exoskeletons consisting of lower-body and upper-body modules, and their combination as full body as well to provide flexible physical assistance as needed. The full-body exoskeleton comprises 27 degrees of freedom, of which 17 are passive and 10 active, which is able to assist people in walking, standing, carrying and handling tasks. In the paper, design of the AXO-SUIT is described. End-user testing results are presented to show the effectiveness of the exoskeleton in providing flexible physical assistance.

We propose an artificial vision algorithm for a semi-autonomous brain-computer interface (BCI). The interface was designed in such a way that users are able to manipulate a robotic arm to pick up an object from a table and place it in one of two possible locations indicated as goal disks, and the manipulation is performed without any concern about continuous control of the final effector. The implemented algorithm is used to obtain, in real time, the positions of the object and the disks in reference to the robot frame. The main techniques used in the proposed algorithm were color segmentation and homography transformation. The implementation of the algorithm allows to obtain the positions of all the items in the table, and it successfully performs pick and place tasks, setting the items on different positions across the table.

This work focuses on a user centered design of a wearable exoskeleton for upper limb of children with spastic cerebral palsy. Characterization of normal kinematics and electromyographic activity during a set of six relevant proposed activities based on a review of literature is performed on a sample of 9 healthy children. Further research is needed to characterized activities on children with spastic cerebral palsy and complete the design of the exoskeleton. Proposed methodology can be used to design more significant technology for the user.

Strategies for gait rehabilitation that employ active orthosis and exoskeletons have been proposed to improve the mobility and to accelerate functional recovery of post-stroke patients. The challenge for these devices is to encourage active participation of the patient and for this purpose, impedance and damping modulation can be applied at the device’s joints during gait. Here, we present the protocol and results of the application of stance control in an active knee orthosis, which works under impedance and damping adjustment based on gait phases. Experimental results of this pilot study carried out on three post-stroke patients showed that our active orthosis offers knee support in 50% of the gait cycle. A positive effect of the controller on the patients, regarding safety during the gait was also found, with a score of 4.64 in a scale of 5, using the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0).

A prosthesis is an electronic-mechanical device that allows the replacement of a lost limb functionality. These features require strict control of the energy used for increment the operating time and patient’s safety. In lower limb prosthetic control, it is fundamental to detect each of the phases of the human gait cycle. For example, during the swing phase, the prosthesis must duplicate the movement of the healthy limb, and in load phase, this movement must be adapted. This article presents the algorithm for spatiotemporal human gait parameter using Teager-Kaiser energy operator and its partial validation.

This article surveys the main lower limb exoskeletons developed, or under development, in Latin-America, under the REASISTE Ibero American Network. There are several groups working in this field, which approaches and results are comparable to those reported by other groups in Europe or North America (ALLOR, CPWalker, BioMot, Kinesis and CHIEF exoskeletons), the overall activity in this field is comparatively limited. Moreover, we have noticed a lack of clinical experimentation, which further prevents the advancement of the filed in Latin-America. The specific conditions of the healthcare systems, as well as the differences among cultures may yield valuable information towards the rethinking of the design of the exoskeletons.

In this work, the development of an electronic instrument to assist in spasticity measurement is presented. The device measures joint angular position of the elbow using inertial measurement units (IMUs) and a monocular camera. A sensor fusion algorithm captures subject’s motion using gyroscopes, accelerometers and camera information. The developed instrument transmits data by wi-fi from a microcontroller to PC, where IMU data is fused with camera data extracted from visual markers. The developed motion tracking system data was compared with a commercial device, showing better results, which encourage its further development for spasticity evaluation.

Back-support exoskeletons have shown the potential to improve workplace ergonomics by reducing the risk of low-back injury. To support the rapidly expanding landscape and to correspondingly promote correct adoption, standard specifications for back-support exoskeletons are desirable. We propose a list of properties and discuss their relevance to industrial applications.

To provide assistance with an active exoskeleton, the control system of the device has to automatically detect the onset of the user’s movement and provide timely assistance, according to the recognized movement. In this paper, we present an algorithm designed to detect the lift movement with an active pelvis exoskeleton, based on a quadratic-discriminant-analysis classifier combined with a rule-based algorithm. The algorithm relies on sensory information acquired from the sensory apparatus of the exoskeleton, without needing additional sensors to be placed on the user’s body. The algorithm was validated in experiments with seven healthy subjects. Participants were requested to execute different actions, i.e. lift and lower a load, stand up, sit down and walk, while wearing the exoskeleton. On average, the algorithm showed an accuracy of 98.7 ± 0.6% in recognizing the lift task; such performance make it suitable for use in real application scenarios.

The objective of this study was to assess the effect of a passive trunk exoskeleton on functional performance and metabolic costs in healthy individuals.Functional performance of 12 work-related tasks was assessed based on objective outcome measures and perceived task difficulty. In addition, we measured energy expenditure during 5 min of repetitive lifting and walking, with and without exoskeleton.Wearing the exoskeleton tended to increase objective performance in static forward bending. Performance in tasks that involved hip flexion decreased and these were perceived as more difficult with the exoskeleton. Wearing the exoskeleton during lifting decreased metabolic costs by as much as 17%, and may reduce the development of fatigue and LBP risk. During walking, metabolic costs increased by 17%. These results indicate the potential efficacy of the exoskeleton to support trunk bending tasks, but also stress the need to allow disengagement of support depending on activities performed.

Industrial wearable exoskeletons and exosuits represent a vibrant technology with revolutionary potentials to enhance the operating conditions, health and safety of the worker. It brings forward the important social and technological goal of helping the workers instead of replacing them. An effective assessment process is a core for the sustainability and deployment of these devices in the industry. We present a process based on the evaluation criteria to validate the Impact on Worker, Appropriation to the Task, Utility to the Task, Usability and Safety. We test this criterion with the help of objective and subjective methods, which depend upon assessment techniques, assessment devices, surveys and subjective scales. In the end, we share our experience of implementing this process, and we point out industrial needs which can help future research and development directions.

A large portion of the working population is affected by back and shoulder pain. Lower back support exoskeletons were introduced as a preventative measure, but they are not widely adopted by the industry yet. Their adoption is hindered chiefly by discomfort, loss of range of motion and kinematic incompatibility. In this work, we discuss the range of motion of the trunk in the sagittal plane, once wearing a flexible exoskeleton and once without wearing an exoskeleton (N = 2).

Lower back pain is a major cause of disability and sick day absences. As lower back pain can result in decreased life quality as well as lower industrial productivity, multiple research groups and companies are looking into possible solutions. One of such solutions could be exoskeletons, that engage and disengage the actuators depending on the movements performed by the user. Otherwise we risk hindering the users movements and increasing his metabolic costs. We implemented an exoskeleton control using finite state machine combined with a Gaussian mixture model movement classifier. By conducting a test battery with a subject wearing the exoskeleton we were able to engage the exoskeleton actuators when appropriate and keep them disengaged to allow a full and unhindered range of motion. The results show our exoskeleton control correctly engages and disengages actuators based on the movements being performed by the user.

Spinal exoskeletons can reduce the cumulative back load of physically demanding working tasks and, thus, have the potential to reduce the risk of low-back injuries. In this work, we perform a comparative design study of active and passive spinal exoskeletons to support stoop-lifts of a 10 kg box. We recorded various healthy subjects performing this motion and created mathematical models of the subjects and of active spinal exoskeletons. The spring characteristics as well as the torque profiles are optimized to reduce the load on the subjects while they are tracking the recorded stoop-lifts. In addition, it is ensured that the exoskeletons remain comfortable to wear during the motion. The obtained results are compared to results from a similar setup using a passive spinal exoskeleton.

Estimation of contact forces between lower limb and orthosis during gait is useful to prevent skin issues in subjects wearing this type of assistive devices. While inverse-dynamics based gait analysis of multibody models is difficult to apply due to the limited accuracy of motion capture systems, a forward-dynamics based analysis in which leg and orthosis are considered as independent entities is shown to provide acceptable results. Contact model parameters are calibrated through comparison of measured and calculated bending torque at the orthosis location where a load cell is installed, and the attained correlation allows to validate the model.

No single muscle model exists that has the same mechanical impedance and force development properties as biological muscle. It is essential to develop a muscle model with the same force limitations and impedance as biological muscle, especially for predictive simulations, as these properties are taken into account when choosing a posture for a specific task. We propose a mechanics-based muscle model that has the same impedance and force development properties as biological muscle by making a small topology change that turns titin, an enormous viscoelastic protein, from acting in parallel to the cross-bridges to acting in series with the cross-bridges.

We present a simulation platform that will enable clinicians to evaluate the effect of different treatment options on gait performance in children with cerebral palsy (CP) in order to select the treatment with the highest potential to normalize the patient’s gait pattern. We present a case study to demonstrate the use of the platform. We created a neuro-musculoskeletal model of a 10-year old female child with mild spastic triplegic CP (GMFCS II) who was treated with single-event multilevel surgery based on medical imaging and motion capture data collected before the surgery. Based on this model, we predicted that the treatment would reduce the capability gap, i.e. the torque deficit of the patient with respect to the joint torques needed for normal walking. This prediction was in accordance with the closer-to-normal post-treatment gait kinetics of the child.

In this document, a general framework for generating bio-inspired walking is outlined. This framework relies on the combination of a musculoskeletal model of the leg and different bio-inspired neural principles for providing activation signals to these virtual muscles. We explored this framework both for humanoid walking – achieving both versatile and human-like gaits – and for human walking assistance.

Due to high degree of freedom and different mechanism foci, hand and arm exoskeletons are usually developed separately and seldom combined together. Hand exoskeletons are typically more complex mechanisms than arm or leg exoskeletons due to the numerous degrees of freedom encapsulated in the hand and the small anatomical structure involved. This study presents the design of a 12 DOF (6 active) reconfigurable hand exoskeleton for rehabilitation that will be installed on the upper limb exoskeletons, EXO-UL8 and BLUE SABINO. Given the mechanism architecture, a nonlinear optimization framework minimizes physical footprint while maximizing mechanism isotropy and device functionality.

This work presents an intuitive graphic interface to make its users aware of potentially risky body configurations while being exposed to external loads. Employing an algorithm we proposed in a recent work, we estimate the human joint torque overloading caused by an external force. This information is used as an input for the graphical interface to provide the user with an intuitive feedback about the strain on each joint. Hence, the users can be aware of the loading states, react to them accordingly, and minimise the risk of injuries or chronic pain. This graphical interface can help the users learn and achieve more ergonomic configurations during industrial job duties.

The paper compares different signal processing algorithms and classifiers to evaluate the accuracy of a BMI based on lower-limb motor imagery. The methods were based on the analysis of the peaks of the different processing epochs for the alpha, beta and gamma EEG bands through the Marginal Hilbert Spectrum, Power Spectral Density and Fourier harmonic components. Data were classified and analyzed by three classifiers: Support Vector Machine, Self-Organizing Maps and Linear Discriminator analysis. Results show accuracy is dependent on the subject, but there is not dependency between the subjects and the methods, and classifiers. Best accuracy results were achieved by using the value of the peak of the Hilbert Marginal Spectrum, obtaining the analytical signal with the Stockwell transform. Regarding the classifiers SOM presented lower accuracy values than SVM and LDA.

We developed a lightweight lower-limb exoskeleton to assist the paretic leg of stroke patients during gait training. The device features compliant actuators separated from the patient’s limb, thus avoiding any gait disruption caused by the actuators’ inertia. The exoskeleton control uses motion data from the healthy leg to extract a reference gait phase. In this context, phase is a continuous variable that tracks the progress of the gait over one cycle and wraps around at the end of the cycle. The extracted phase information is used to time the assistive torque acting on the impaired leg. Control of the assistive torque is implemented as a force control acting on a time-varying linear system representing the actuator and exoskeleton. Results from one experiment show how the exoskeleton helps improve knee flexion during the swing phase of the gait cycle.

A significant number of people suffer from musculoskeletal pathologies, which result in limitations in sit-to-stand (STS) movement or during locomotion. Allowing disabled people to stand, can reduce secondary conditions, increasing their life expectancy and reducing healthcare costs. Exoskeletons can be used to support human motion, helping to solve these problems. This work regards a preliminary study to develop a passive exoskeleton to support sit-to-stand movement. For that purpose, a biomechanical model was implemented in a computational multibody dynamics software, to estimate reaction forces and moments at the joints.Data concerning STS movement with arm support and STS without arm support was collected. Outcomes include reaction forces and moments calculated at the ankle, knee and hip joints, giving insights about the torque and power requirements for the exoskeleton design.Preliminary studies revealed that 10% of the force required to perform the standing motion can be granted through the user’s arms action force.

This work was devoted to preliminary test the Achilles ankle exoskeleton and its NeuroMuscular Controller (NMC) with a test pilot affected by incomplete spinal cord injury. The customization of the robot controller, i.e. a subject-specific tailoring of the assistance level, was performed and a 10-session training to optimize human-robot interaction was finalized. Results demonstrated that controller tuning was in line with the functional clinical assessment. NMC adapted to the variable walking speed during the training and the test pilot was successfully trained in exploiting robotic support and also improved his performance in terms of walking speed and stability. After the training, a higher speed could also be achieved during free walking and hence a slight unexpected rehabilitation effect was evidenced.

The goal of this study is to understand the postural adaptations characterized by the whole body center of mass (COM) for individuals with SCI while walking with powered robotic exoskeletons, EksoGTTM and ReWalkTM. COM excursions showed a greater medial-lateral weight shift approach while walking in the EksoGTTM compared to a more forward-lean approach in the ReWalk™, however, postural trunk lean was significantly (p < 0.05) higher in the ReWalkTM. Understanding the effects of exoskeleton designs on posture and sway is crucial towards developing effective and efficient training protocols for rehabilitation and recovery post SCI.

The objective of this research is to identify the demographic, physiological, kinematic and biomechanical determinants of exoskeleton assisted gait speed for individuals with a spinal cord injury (SCI). High number (300) of gait cycles across multiple time-points were analyzed to identify the parameter estimates from mixed model for dependent variable walk speed. Step length, step width, single stance time did not contribute to walk speed whereas trunk lean mass, stride length, step frequency were the most significant contributors. These variables were more significant than any of the spatial temporal parameters that are associated with human gait. Future research should determine the relative contributions of each independent variable to walk speed for different devices. Understanding the effects of exoskeleton/human interface for different devices is crucial for developing effective/efficient training protocols for community ambulation, rehabilitation and recovery post SCI.

To date, exoskeletons typically only allow paraplegic users to stand or walk quadruped-like with crutches to maintain balance. The problem with today’s robotic assistive devices that are supporting or restituting stance and walking in paraplegic users is inadequate posture control, which endangers balance and increases the likelihood of a fall occurring. We address this issue in this Methods article by describing the posture-movement interrelations in humans, suggesting the inclusion of posture control in assistive robotic devices, and recommending their experimental testing prior to application for biped use.

Recent effort in exoskeleton control resulted in reduction of human metabolic consumption during ground-level walking. In this context, solutions that would enable biomechanical and metabolic benefits across large repertoires of motor tasks would be central in supporting the human in both medical and industrial scenarios. With this idea in mind we created a muscle-driven controller based on electromyography (EMG)-driven musculoskeletal modeling that we interfaced with the robotic bi-lateral Achilles ankle exoskeleton previously developed in our group. Preliminary results on one healthy individual show the possibility of continuously decoding EMG-dependent muscle force and resulting ankle joint moment patterns in real-time across a range of diverse motor tasks. We demonstrate that this information can be used to establish a human-exoskeleton interface with high-resolution at the level of single muscle mechanics.

This study presents a smart insole system made by pressure sensitive fabric. This fabric insole has 360 sensing arrays. Therefore, it can measure the foot plantar pressure distribution with a high resolution. An experiment was carried out to validate this system with the reference measurement system (F-scan). Ten participants were involved in an experimental study. The results showed that the fabric insole can measure the foot plantar pressure distribution accurately, with an average RMSE ranged from 22.46 kPa to 38.54 kPa for different balancing tasks.

Improving stability of people wearing a lower extremity Wearable Exoskeleton (WE) is one of the biggest challenges in the field. The goal of this preliminary study was to improve balance recovery from perturbations in people with incomplete Spinal Cord Injury (SCI) assisted by a WE with specifically developed balance controller. The WE has actuated ankle and knee joints, which were controlled by using a body sway-based balance controller. Two test pilots participated in 5 training sessions, devoted to enhance the use of the robot, and in pre/post assessments. Their balance during quiet standing was perturbed through pushes in forward direction.The controller was effective in supporting balance recovery in both tests pilots as reflected by a smaller sway amplitude and recovery time when compared with a minimal impedance controller. Moreover, the training resulted in a further reduction of the sway amplitude and recovery time in one of the test pilots whereas it had not an additional beneficial effect for the other subject.In conclusion, the novel balance controller can effectively assist people with incomplete SCI in maintaining standing balance and a dedicated training has the potential to further improve balance.

Human locomotion is a complex movement task, which can be divided into a set of locomotor subfunctions. These subfunction comprise stance leg function, swing leg function and balance. Each of these locomotor subfunctions requires a specific control of individual muscles in the human body. We propose a novel method based on sensor-motor-maps to identify the appropriate motor control settings based on sensory feedback loops. Based on template models, both the biomechanical as well as the neuromuscular dynamics of gait can be studies and described at different levels of detail.

This talk presents an overview of the development of a full-body model-based passivity approach for posture control of a humanoid robot. The controller exploits passivity properties to provide suitable control inputs for the humanoid robot without requiring a solution to the inverse kinematics problem of the full kinematic chain. The controller has been validated in numerous experiments using the torque-controlled humanoid robot TORO, developed at the German Aerospace Center (DLR).

XoSoft is a modular soft lower-limb exoskeleton to assist people with mobility impairments. Being a modular system, it comprises of ankle, knee and hip elements, which can be used in different configurations. XoSoft follows a user centered design strategy achieved by involving primary, secondary and tertiary end users as participatory stakeholders in the design and development process. This paper presents the evolution of the different prototypes developed during the project, as well as the testing stages. From the Alpha prototype, built from available technologies, to the Gamma prototype, which includes advanced textiles technologies, smart materials for sensing and actuation, biomimetic control and connected health monitoring and feedback system.

Upper-limb paresis is a main disabling condition in stroke and neurological diseases and rehabilitation is essential for recovering/maintaining function. Upper-limb weight support may help/enable these patients performing movements against gravity thus allowing for task oriented interventions. In this framework, an exoskeleton for upper-limb weight support was developed. In this preliminary study the system was tested in a small group of neurological patients (N = 12) to verify the overall usability and its efficacy in assisting patients during functional movements against gravity. Patients performed some functional tasks of the ARAT test both with and without the exoskeleton. The system seems effective as it enabled even the most impaired patients performing the tasks. All patients could wear the exoskeleton and complete the tasks. Usability of the system was assessed as adequate for a use inside a clinical study. Future work will focus on verifying the efficacy of task-oriented intervention performed using the exoskeleton.

The main goal of the Symbitron project was to develop a safe, bio-inspired, personalized wearable exoskeleton that enables SCI patients to walk without additional assistance, by complementing their remaining motor function. Here we give an overview of major achievements of the projects.

The Robo-Mate project developed industrial exoskeletons to reduce the risk of physical injury associated to manual material handling tasks. Prototypes targeting different body areas were evaluated for their effectiveness but also for their applicability and usability in the field. Encouraging evidence of their effectiveness and informative feedback from the field have driven further research and development. This has additionally led the initiation of a new collaborative project, which aims at continuing technical advancements as well as at promoting the translation to diverse areas of application.

Robotics-enabled technologies for assistive and rehabilitative applications have gained an increasing attention, both in academic and industrial research settings, as a promising solution for human sensory-motor system recovery. However, many constraints remain that limit their effective employment in everyday-life, mainly related to cost, usability and users’ acceptance. The Softpro project proposes to completely reverse such paradigm, starting from the analysis of the needs from patients and the careful investigation of the sensory-motor human behaviour, capitalizing on the framework of synergistic control and soft robotics. The final goal is to study and design simple, effective and affordable soft synergy-based robotic technologies for the upper limb, such as new prostheses, exoskeletons, and assistive devices which can be useful and accessible to a wide audience of users. To pursue such an ambitious objective, SoftPro has put together research groups who laid the neuroscientific and technological fundamentals underpinning the project approach, a net of international collaborations and numerous and qualified industrial partners, which is expected to produce a strong impact on both research and innovation.

Robots are entering our everyday life at an exponential pace. Benchmarking can help researchers and developers to improve their systems, as well as providing end-user with easy-to-understand “performance scores” able to identify the best solution for their needs. Unfortunately, a benchmarking methodology for robotics is still not available. The EUROBENCH project wants to provide rigorous tools at both software and hardware level, to allow companies, researchers and users to test robotic systems under multiple facets. The project, initially focused on bipedal robotics technologies (exoskeletons, prostheses, humanoids), will offer funding opportunities to third parties to participate in the development and validation of the different components of the framework.

When selecting actuators for assistive exoskeletons, designers face contrasting requirements. Overdimensioned actuators have drawbacks that compromise their effectiveness in the target application (e.g. performance, weight, comfort). In some cases, the requirements on the powered actuator can be relaxed exploiting the contribution of an elastic element acting in mechanical parallel. This contribution considers one such case and describes an approach to fit the actuation requirements closely to the task dynamics, thereby mitigating the drawbacks of overdimensioned actuators.

This paper presents the results of the force measurements performed with an industrial-grade load cell embedded in the linkage of a hand exoskeleton. The force sensor is placed such that it measures the interaction force between the index finger of the user and the actuator that controls its motion. This architecture has been used in an experimental test in which users had to grasp an object (cup or bottle), interact with it and then release it. Force measurements shows that this disposition allows to discern between successful and unsuccessful grasping.

Intelligent soft exoskeletons are developed to be used unsupervised and continuously on a large scale in normal daily situations. As they miss the stiffness of the structural components of traditional robotic devices, traditional robotic movement assessment are rendered useless, as they assume structural segment rigidity. This all requires a radical different approach towards (remote) monitoring and feedback of data relevant to a host of different type users: clinicians and therapists responsible for training and well-being of patient, caregivers, maintenance technicians and even the exoskeleton’s control system. This paper proposes such a system, one implementation of which is developed and tested within the XoSoft soft exoskeleton project. It provides continuous remote (partly IMMU based) assessment of 3D kinematics and kinetics, control system activity, subject activity pattern and derived movement pattern parameters. It also is structured in a maximally flexible way facilitating the ever-shifting, optimal distribution of functional software modules over more peripheral and central hardware to accommodate for fast changes in specifications and technical and practical constraints.

We present the manufacturing and the implementation of a multi-modal sensory soft hand for the interaction with conductive and non-conductive objects. The hand sensors were mounted on two fabric layers with three sensory modularities: touch, proximity, and curvature. Servoing behavior is generated based on the estimation of the center of touch (force sensitive resistor) and the center of proximity (proximity sensitive capacitor). Results are presented on human subjects wear the hand, and a set of vibration motors that work as haptic feedback for the center of stimulation. Driven by vibration, the system guides the subject to explore conductive objects. Servoing behavior is generated based on the estimation of the center of stimulations without visual feedback.

Soft Robotic Pad (SRP), as a new class of soft pneumatic actuator (SPA), is a two-dimensional pad-like SPA that can be programmed to achieve different surface morphing. Recently, the successful fabrication has proven the feasibility of functional SRPs. However, there are issues to be solved so that the SRP can withstand high pressure for practical applications. This paper, based on the first version of the SRP fabrication method, presents some modifications in the method and discusses their pros and cons. Firstly, the incorporation of stiffness customization and patterning method into the SRP fabrication not only simplifies the SRP morphing design, but also makes many morphing modalities possible. Furthermore, the use of larger carbon-fiber rods and the channel filling process improve the SRP strength, which qualifies them to many applications. As an envisioning step, we presents a design of a wearable assistive SRP for elbow flexion. With this fabrication method, the SRP with its unique shape and morphing capabilities has great potential in wearable robotics especially for human joint rehabilitation.

The shoulder is one of the most complex joints in the human body due to its extensive range of motion. Exoskeletons must accommodate the shoulder’s capabilities in order to be effective. Soft robotic actuators have found their way into upper limb exoskeletons; however, current designs do not provide a mechanism for adjusting the structure of the exoskeleton in order to tailor-fit it onto the user. We have created a modular, pneumatic, soft robotic exoskeleton that is capable of mechanical and structural reconfiguration: the Exosleeve. Reconfiguration provides the potential to ensure that the device correctly matches the user’s requirements. The ability of the Exosleeve to provide assistance in performing limb motion was preliminarily assessed through a pilot test of three healthy subjects. Subjects were instructed to perform shoulder abduction exercises while surface electromyography measured muscle activation under various conditions. The test showed that utilization of the Exosleeve reduces muscle activation.

This work presents an active orthotic device with a wearable structure corresponding to the natural motions of the human that can be used for motion capturing and mobility assisting. The exoskeleton structure includes left and right upper limb, left and right lower limb fabricated with light materials and powered by pneumatic artificial muscles. The proposed exoskeleton provides more than fifteen degrees of freedom and can operate in three modes: Motion tracking and data exchange with virtual reality (VR); Haptic device with force-feedback that can display sensory information from a virtual reality to the user; Assistive and rehabilitation device in cases of impaired muscles.The design and development has been carried out in Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria.

Rigid and soft wearable robots have promising complementary properties that could be exploited to cover a broad range of applications and needs. While the former are ideal when high forces, accurate position and high dynamics are required, soft devices are more practical when portability and comfort are demanded. In this preliminary study, we quantify this duality by comparing the technical characteristics of a soft exosuit and a rigid exoskeleton and measuring their biomechanical and physiological effect on the elbow movements of healthy subjects.

Soft materials show numerous advantages compared to rigid ones in exosuit devices. We present the design of a soft wearable elbow assistance device with flexion and extension actuations. Commercially available butyl rubber tubes have been used as a pneumatic actuator. Tubes are enveloped by a lightweight polyester fabric to eliminate a non-homogeneous expansion. The surrounding fabric in turn is mounted on a clothes fabric as zigzag paths. The exosuit is lightweight, shock resistant, simple to manufacture, and low cost. The subjective experiments show a reduction average of 48% in the Rectified & integrated raw electromyography signal of the brachialis muscle during a rhythmic flexion/extension sequence while lifting weights (3 and 5 [kg]). Results indicate a significant assistance with respect to the other existing soft elbow exosuits.

Watchband-type soft pneumatic actuators were prototyped and tested by motion experiments. The actuators are soft device which is made from thermoplastic copolyester (TPC) by 3D printer. The actuator is for a device for feedback of prosthesis grasping force. The feedback device resembles a watch, and the parts corresponding to the watch wristband are actuators shaped like a thumb and index finger. The actuator of finger-type bands can press an intact wrist of amputees who use a prosthesis by wrapping around the wrist in accordance with the grasping motion of the prosthesis hand. In experiments, actuator’s various configurations using different combination of thickness of the body were compared by measuring output forces and range of motion (ROM). As a result of the comparison, the optimal configuration which improve the force and ROM was found.

Walking is a fundamental but important activity for independent daily life. We designed an intuitive controller (called negative damping controller) for the elderly to walk more efficiently. The controller behaves as a negative damping for the hip joint to eliminate natural energy dissipation terms and is capable of mimicking the biological torque profile. The primary objective of this study is to evaluate the effects of the controller on the biomechanical and physiological aspects of gait. As a first step, we measured gait parameters and muscle activation levels for a subject during overground walking with and without exoskeleton at self-selected speed. The experimental results show that the negative damping controller has the potential to enable the wearer to walk overground with larger hip range of motion and lower muscle activation: the hip range of motion increased about 21.9% and the average muscle activation levels decreased about 18.0% in rectus femoris and about 23.7% in bicep femoris.

Exoskeletons were recently proposed to reduce the risk of musculoskeletal disorders for workers. To promote adoption of active exoskeletons in the workplace, control interfaces and strategies have to be designed that overcome practical problems. Open challenges regard sensors invasiveness and complexity, accurate user’s motion detection, and adaptability in adjusting the assistance to address different tasks and users. Focusing on back-support exoskeletons, different control interfaces and strategies are discussed that aim at automatically driving and modulating the assistance, according to the activity the user is performing.

Among the most challenging aspects of the current bio-robotics trends, a place of honor is certainly reserved to the assistance to physically impaired people during the Activities of Daily Living (ADLs). The aim of this work is to assess the interaction between an assistive hand exoskeleton, controlled through surface ElectroMyoGraphy (sEMG) signals, and its user. A new control strategy, which focuses mainly on the wearability and the usability of the system, is presented. Promising results of two preliminary tests, conducted in collaboration with the “Don Carlo Gnocchi” Foundation, are also reported.

This study is devoted to investigate the influence of a knee orthosis for human walking by using a mathematical model for a 7-links planar biped - composed with two identical legs, two feet and one trunk - with an orthosis attached to both thigh and calf, during walking. In the first part, we design a cyclic walking gait in the sagittal plane for human without the orthosis. The second part we consider that the human looses his muscular possibilities in one of his knees. To overcome his handicap the human is equipped of a knee orthosis. We analyse the positive effect of the orthosis over the assisted knee to track the previous designed reference trajectory. By using at each time an optimisation algorithm, we minimise the torques provided by the human. The numerical tests confirm the possibility to reduce the torque produced in the disabled knee. The next step is to take into account explicitly an information from EMG signal during a walking to modulate the power of the orthosis.

Tripping is a major cause of falls in elderly people. Considering that fall related injuries have severe consequences on their quality of life, there is an urgent need to develop preventive solutions. One such solution could be the use of assistive exoskeletons. In this work we investigated the effects of a hip exoskeleton on human posture under the influence of an external perturbation. During normal standing of a subject we applied a forward pulling force at the chest and then enabled or disabled the exoskeleton randomly. By analysing the kinematics of the human body we compared responses to perturbations when the exoskeleton was enabled or disabled. The results show that the exoskeleton efficiently reduced the forward inclination of the trunk by 40%.

Arm swing asymmetry brought on by hemiparesis or hemi-neglect due to stroke causes increased ground reaction moments during walking. Thus, increasing loading asymmetry of the lower limbs and the metabolic load of walking. The system presented here consists of wearable bracelets, designed to help decrease arm swing asymmetry in people with stroke. Design of the bracelets and outcomes of pilot tests with a healthy subject with artificially induced arm swing asymmetry are presented. The healthy subject was able to utilize the vibration feedback to reduce arm swing asymmetry with involuntary increase in arm swing magnitude. Thus, exploration of the effects of using this system with stroke patients is warranted.

Conducting an FMEA for the design of a planetary gear transmission for exoskeletons enables decision making based on the interdependence between design parameters and the device requirements, as well as an early identification of several functional risks. Therefore, the use of FMEAs in the design of wearable robotic devices could contribute to higher design robustness, and ultimately result in a broader acceptance of future active wearable robotic devices.

This paper introduces the concept of Series Elastic Link which exploits the inherent elasticity of flexible links to implement compliant actuation and control using lightweigt and low cost components.

Advantages like electromagnetic field immunity, fracture toughness, high strain limits, flexibility in bending and impact resistance of polymer optical fibers (POFs) are beneficial for applications that involve embedment in flexible structures. Since insoles are one of these flexible structures that may be used in different wearable applications, POFs can be applied and this paper proposes the application of POF sensors in insole instrumentation with two different approaches: intensity variation-based and polymer optical fiber Bragg gratings (POFBGs). Results show that both approaches present low errors with root mean squared errors (RMSEs) of 45.17 kPa for the plantar pressure monitoring with the POFBG-based insole and 5.30 N for the ground reaction force measurement with the intensity variation sensors. These results demonstrate the feasibility of POF sensors applications in flexible structures and in wearable applications such as insoles and soft robotics instrumentation.

A device that supports hand function may significantly improve the quality of life of patients with muscular weakness. Since tight constraints such as size and weight are placed upon the device, complexity of the hardware and functional performance should be carefully balanced. A novel force transmission mechanism based on tape springs is presented for use in a hand orthosis. The actuator force is transmitted to the finger by a system consisting of a tape spring, two slider blocks and an end stop per finger. The tape spring allows for bending in one direction, and resists bending in the other direction. A prototype with the new mechanism is constructed. The low profile together with the ability to transmit large forces makes this mechanism suitable for hand orthoses.

This work introduces the SmartPFD, a Personal Flotation Device (PFD)/Life vest featuring independently inflatable air compartments. Unlike off-the-shelf inflatable PFDs, the SmartPFD is designed to modulate the inflation of its compartments based on the wearer’s orientation and depth, with the aim of optimizing the device’s righting ability. Preliminary results suggest that by properly sequencing the activation of the compartments, the time required to turn the wearer face up can be reduced.

In the field of wearable robots, high power density and highly efficient actuators are required to handle the high-power motion without becoming heavy and bulky and hence hamper their mobility. Typically, electrical motors are used in combination with high gear ratio gearheads or lever arms in order to achieve the required torques. These gearboxes consist mainly out of several stages of simple Planetary Gear Trains (PGTs). However, this approach leads to big and heavy gearboxes when high torque is needed. An alternative, more compact, design to obtain the required torque increase can be achieved using Compound Planetary Gears (C-PGTs). It is shown that the latter mechanism can obtain gear ratios up to 1:600 while withstanding an output torque of 100 Nm.

Developing wearable robotic systems for children’s hand rehabilitation highlights several issues during the design phase due to the difficult interactions with the patients and the high adaptability these devices require to fit fingers always growing. In this research work, the authors propose a model-based approach which exploits only a photograph of the hand to automatically generate a tailor-made device capable of replicating hand trajectories. A real device has been developed and tested on a patient after three growing steps in order to assess its kinematic compliance with fingers.

In this study, a bio-joint shaped knee joint exoskeleton is presented. This design is meant for avoiding misalignment of the exoskeleton joint with the biological knee joint. For this purpose a cam mechanism has been designed to prevent the misalignment from translation of the femur on tibia. Additionally, walking and sit-to-stance is passively assisted with a spring element that is activated with the heel contact. A single spring is used for both walking and sit-to-stance, due to the similar characteristics of the gait cycle and initial phases of the sit-to-stance in joint stiffness.

This study describes the optimized design of a passive lower limb exoskeleton for workers in the industry. The exoskeleton is aimed at helping workers who carry heavy loads, by supporting their posture and reducing stress in their knees which would prevent future injuries. However, most of the previous passive designs are insufficient in a way that they are bulky. Therefore, this study is focused on achieving lightweight passive exoskeleton. Topology optimization has been carried out to reach this goal. The results are validated using finite elements methods, in ANSYS environment.

Mechanical loading of the spine is a known risk factor for the development of low-back pain. The objective of this study was to assess the effect of an inclination-controlled exoskeleton on spinal compression forces during lifting with various techniques. Peak compression decreased on average by around 20%, and this was largely independent of lifting technique.

Industrial workers suffer from musculoskeletal disorders. Especially, the shoulder disorder affects many working movements. To reduce it, various assistive devices have been developed. However, because of the complex shoulder, there are several issues to apply the devices to the actual workspace, such as bulky size or heavyweight. In this paper, a novel mechanism consisting of three sub-mechanisms is suggested. It is focused on the weight support as the main function. This target-oriented approach can reduce the complexity of the mechanism and can lead to a light and compact structure. The mechanism is designed to compensate three main issues between the exoskeleton and shoulder joint: various arm raising direction at the initial posture, protraction/retraction, and scapulohumeral rhythm. The design parameters were optimized by using the center of the rotation of the shoulder, and the whole structure was designed with a trajectory error of 5 mm or less.

In this paper, the design of a new exoskeleton to enhance and support the human abilities in industrial maintenance environments is presented. The motivation to design this device arises from the necessity to reduce or eliminate musculoskeletal disorders caused by manual movement of heavy loads, prolonged raised arm working postures and repetition of movements associated with the installation and maintenance of industrial facilities.

Long exposure to overload and vibration transmission on the upper limb are among the high risk injury factors in industrial environments. They contribute to the development of musculoskeletal disorders, which can lead to economic and social setbacks. To address this issue, robotic systems have been developed that act either as an autonomous system or in collaboration with the workers. In this direction, and with the aim to develop a system that contributes to a simultaneous reduction of the overloading and vibration transmission, we present a novel wearable soft robotic hand-arm system. Preliminary experimental results in a vibrational tool use are reported to shown the potential of the system in improving worker ergonomics.

Soft assistive devices constitute a promising alternative to help people with mobility impairments. Nevertheless, some issues as the control of these systems preclude from their generalized usage in common daily activities. The objective of this paper is to obtain the activation profile for controlling a clutched spring to store and release energy in a way that helps the subject to achieve a specific movement target. To do this, a parameter and partially constrained optimization method has been implemented. The results obtained showed a clutch activation profile which is synchronized with a reduction of the hip flexion torque exerted by the subject. Additionally, significant computational times savings have been obtained due to important reductions of the size of the optimization problem introduced by a partitioning of the state and control vectors.

Exoskeletons have been interest of researchers and developers spanning a wide range of applications. Active and passive or quasi-passive exoskeletons are being developed. For this latter category, the actuator parameter tuning is generally based on optimization studies. This paper studies how the definition of the objective function affects the passive or quasi-passive exoskeleton actuators configuration and parameters. It also provides indications on how focusing solely on energy optimization might result in an assistance that could alter the user behaviour. Therefore, usability of the exoskeleton and user comfort could be negatively affected. Finally, as a result of the optimization output analysis, we discuss about the advantages of designing a quasi-passive exoskeleton.

Stroke often causes flexor hypertonia as well as weakness of finger extension. This limits functionality of the hand degrading independent ability to perform upper limb activities of daily living (ADL’s). Hand rehabilitation post stroke is vital to regaining functionality in the affected limb, leading to improved independence and quality of living. In this paper the development of DigEx and MIDAS passive arm orthoses are detailed. A quick-change cam system is implemented featuring one-handed cam swapping. This provides the ability to vary assistance levels to improve usability and independence for the user. Pulleys and bearings are added to reduce friction caused by mechanical contacts and material failure. Initial tests with the prototype are promising.