Posts Tagged Exoskeleton

[Abstract] An Elbow Exoskeleton for Upper Limb Rehabilitation With Series Elastic Actuator and Cable-Driven Differential

Abstract

Movement impairments resulting from neurologic injuries, such as stroke, can be treated with robotic exoskeletons that assist with movement retraining. Exoskeleton designs benefit from low impedance and accurate torque control. We designed a two-degrees-of-freedom tethered exoskeleton that can provide independent torque control on elbow flexion/extension and forearm supination/pronation. Two identical series elastic actuators (SEAs) are used to actuate the exoskeleton. The two SEAs are coupled through a novel cable-driven differential. The exoskeleton is compact and lightweight, with a mass of 0.9 kg. Applied rms torque errors were less than 0.19 Nm. Benchtop tests demonstrated a torque rise time of approximately 0.1 s, a torque control bandwidth of 3.7 Hz, and an impedance of less than 0.03 Nm/° at 1 Hz. The controller can simulate a stable maximum wall stiffness of 0.45 Nm/°. The overall performance is adequate for robotic therapy applications and the novelty of the design is discussed.

via An Elbow Exoskeleton for Upper Limb Rehabilitation With Series Elastic Actuator and Cable-Driven Differential – IEEE Journals & Magazine

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[Abstract] Robotic Techniques Used for Increasing Improvement Rate In The Rehabilitation Process Of Upper Limb Stroke Patients – Full Text PDF

Abstract

The rate of stroke patients in Pakistan is increasing, resulting in the decrease mobility of the patients. The movement of upper limb stoke patient is decreased due to the weakness and loss of joint control in his upper body. To improve the coordination of movement of the upper limb stroke patients, many methods e.g. passive and active modes for improving the disrupted mobility are introduced. The objectives of this paper are to first review the studies on upper limb stroke patients and the techniques used for increasing the improvement rate through physical therapy by exoskeleton and evaluation of the performance of the patient using methods such as quantification and graphical representations so that it can be shown to the patient for his motivation to improve further. The paper introduces a mechanical design of exoskeleton with 1 degree of freedom for elbow and 2 degrees of freedom for shoulder movement for rehabilitation of joints of stoke patients. It also mentions the safety that will be taken in the process so that the exoskeleton is safe to use when it is in contact with human. The model of the exoskeleton has the characteristic of being modular and easily operable and use admittance control strategy. Control strategy of the exoskeleton is discussed to maintain the position and orientation of the device and also is able to cater the gravitational attraction which plays an important part in the movement of the actuators. The mathematical model of motion attained due to the degrees of freedom of the exoskeleton is then evaluated and the lastly areas where the future work of exoskeleton can be done are discussed.

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via Robotic Techniques Used for Increasing Improvement Rate In The Rehabilitation Process Of Upper Limb Stroke Patients | Sukkur IBA Journal of Computing and Mathematical Sciences

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[WEB PAGE] Ekso Bionics Unveils the EksoNR Neurorehabilitation Device

EksoNR, the latest exoskeleton from Ekso Bionics, features EksoView, a new touchscreen controller that allows therapists to intuitively adapt assistance to challenge patients using real-time feedback. (Photo courtesy of Ekso Bionics Holdings Inc)

EksoNR, the latest exoskeleton from Ekso Bionics, features EksoView, a new touchscreen controller that allows therapists to intuitively adapt assistance to challenge patients using real-time feedback. (Photo courtesy of Ekso Bionics Holdings Inc)

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The EksoNR is a next-generation EksoGT exoskeleton device developed by Ekso Bionics Holdings Inc to aid the neurorehabilitation of patients recovering from stroke and spinal cord injury, and to help them learn to walk again with a more natural gait.

Among the EksoNR’s new features and enhancements is EksoView, a new touchscreen controller that allows therapists to intuitively adapt assistance to challenge patients using real-time feedback and perform outcome measures during use.

Held in the palm of a therapists’ hand, EksoView provides visualization of various exercises beyond gait training, such as balancing, squatting from sit-to-stand positioning, lifting one leg, or standing in place, to actively engage patients and enhance the use of these beneficial features.

Another feature is the optimized SmartAssist software, developed to enable EksoNR to have a smoother and more natural gait path when transitioning between steps.

SmartAssist also gives gait symmetry and posture feedback and allows therapists to track patient progress with the upgraded EksoPulse, a cloud-based analytics solution. EksoPulse now uses rehabilitation data to generate insightful metrics and graphs for therapists and administrators to monitor patient progress and outcomes, Ekso Bionics notes in a media release.

“Ekso Bionics is committed to developing the latest exoskeleton advances for rehabilitation. We continue to innovate to ensure physical therapists have access to the latest tools to deliver better patient outcomes and superior care in neurorehabilitation,” says Jack Peurach, chief executive officer and president of Ekso Bionics, in the release.

“EksoNR is a full neurorehabilitation tool that is effective, intuitive, and differentiating. There is an increasing demand for adoption, as our technology sets rehabilitation centers apart,” he adds.

EksoNR is cleared by the US Federal Drug Administration for stroke and spinal cord injury rehabilitation. The device is also CE-marked and available in Europe.

Ekso Bionics will begin taking orders for EksoNR immediately. Existing customers will have the option to upgrade, the release continues.

[Source: Ekso Bionics]

 

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[WEB PAGE] Wearable robots usher in next generation of mobility therapies – CORDIS

Wearable robots that can anticipate and react to users’ movement in real time could dramatically improve mobility assistance and rehabilitation tools.

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Wearable robots are programmable body-worn devices, or exoskeletons, that are designed to mechanically interact with the user. Their purpose is to assist or even substitute human motor function for people who have severe difficulty moving or walking.

The BIOMOT project, completed in September 2016, has helped to advance this emerging field by demonstrating that personalised computational models of the human body can effectively be used to control wearable exoskeletons. The project has identified ways of achieving improved flexibility and autonomous performance, which could assist in the use of wearable robots as mobility assistance and rehabilitation tools.

‘An increasing number of researchers in the field of neurorehabilitation are interested in the potential of these robotic technologies for clinical rehabilitation following neurological diseases,’ explains BIOMOT project coordinator Dr. Juan Moreno from the Spanish Council for Scientific Research (CSIC). ‘One reason is that these systems can be optimised to deliver diverse therapeutic interventions at specific points of recuperation or care.’

However, a number of factors have limited the widespread market adoption of wearable robots. Moreno and his team identified a need for wearable equipment to be more compact and lightweight, and better able anticipate and detect the intended movements of the wearer. In addition, robots needed to become more versatile and adaptable in order to aid people in a variety of different situations; walking on uneven ground, for example, or approaching an obstacle.

In order to address these challenges, the project developed robots with real-time adaptability and flexibility by increasing the symbiosis between the robot and the user through dynamic sensorimotor interactions. A hierarchical approach to these interactions was taken, allowing the project team to apply different layers for different purposes. This means in effect that an exoskeleton can be personalised to an individual user.

‘Thanks to this framework, the BIOMOT exoskeleton can rely on mechanical and bioelectric measurements to adapt to a changing user or task condition,’ says Moreno. ‘This leads to improved robotic interventions.’

Following theoretical and practical work, the project team then tested these prototype exoskeletons with volunteers. A key technical challenge was how to combine a robust and open architecture with a novel wearable robotic system that can gather signals from human activity. ‘Nonetheless, we succeeded in investigating for the first time the potential of automatically controlling human-robot interactions in order to enhance user compliance to a motor task,’ says Moreno. ‘Our research with healthy humans showed such positive and promising results that we are keen to continue validation with both stroke and spinal cord injury patients.’

Indeed, Moreno is confident that the success of the project will open up potential new research avenues. For example, the results will help scientists to develop computational models for rehabilitation therapies, and better understand human movement in more detail.

‘In the project we also defined novel techniques to evaluate and benchmark performances of wearable exoskeletons,’ says Moreno. ‘Further innovation projects are planned by consortium members to follow up on this research, and to exploit developments in the field of human motion capture, human-machine interaction and adaptive control.’

For further information, please see:
project website

via Wearable robots usher in next generation of mobility therapies | News | CORDIS | European Commission

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[ARTICLE] Development of low-cost portable hand exoskeleton for assistive and rehabilitation purposes – Full Text PDF

Abstract

The design of an aid for the hand function based on exoskeleton technologies for patients who have lost or injured hand skills, e.g. because of neuromuscular or aging diseases, is one of the most influential challenge in modern robotics to assure them an independent and healthy life. This research activity is focused on the design and development of a low-cost Hand Exoskeleton System (HES) for supporting patients affected by hand disabilities during the Activities of Daily Living (ADLs). The device can be also used during the rehabilitative sessions to better recovery the dexterity of the user’s hand. This paper presents a compact design concept for a portable hand exoskeleton. This prototype has been developed thanks to the collaboration between the Department of Industrial Engineering (DIEF) of the University of Florence, and the Rehabilitation Engineering Laboratory of the ETH, Z¨ urich, during the eNTERFACE16 Workshop, hosted by the University of Twente.
Testing sequence

Testing sequence

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[Abstract + References] Preliminary Design of Soft Exo-Suit for Arm Rehabilitation – Conference paper

Abstract

Every year, millions of people experience a stroke but only a few of them fully recover. Recovery requires a working staff, which is time consuming and inefficient. Therefore, over the past few years rehabilitation robots like Exoskeletons have been used in the recuperation process for patients. In this paper we have designed an Exosuit which takes into considerations of the rigid Exo-Skeleton and its limitations for patients suffering from loss of function of the arm. This paper concentrates on enabling a stroke affected person to perform flexion-extension at elbow joint. Validation of the developed model on general population is still needed.

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[ARTICLE] Mechanical Design of Exoskeleton for Hand Therapeutic Rehabilitation – Full Text PDF

ABSTRACT 

In this study an exoskeleton is designed for hand in therapeutic rehabilitation. The mechanical design is manufactured in consideration of anthropometrical measurements of the hand studied from literature. Kinematic model of the hand exoskeleton was obtained by results of position, velocity and torque-moment analysis.
The exoskeleton has a single degree of freedom (DOF) for the PIP and MCP joints. Basic four-bar linkage mechanisms are used in the exoskeleton. With this design, while movements (flexion and extension) occurs in both joints at the same time, angular displacement come out as in healthy hands. Linkage lengths aroptimized to achieve the targeted angular dynamics. The manipulation of the exoskeleton is actuated by a linear
servo motor.

Continue —>  Mechanical Design of Exoskeleton for Hand Therapeutic Rehabilitation

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Fig 2 Hand Rehabilitation System

 

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[Abstract + References] An Exoskeleton Design Robotic Assisted Rehabilitation: Wrist & Forearm – Conference paper

Abstract

Robotic systems are being used in physiotherapy for medical purposes. Providing physical training (therapy) is one of the main applications of fields of rehabilitation robotics. Upper-extremity rehabilitation involves shoulder, elbow, wrist and fingers’ actions that stimulate patients’ independence and quality of life. An exoskeleton for human wrist and forearm rehabilitation is designed and manufactured. It has three degrees of freedom which must be fitted to real human wrist and forearm. Anatomical motion range of human limbs is taken into account during design. A six DOF Denso robot is adapted. An exoskeleton driven by a serial robot has not been come across in the literature. It is feasible to apply torques to specific joints of the wrist by this way. Studies are still continuing in the subject.

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Fig. 1. Wrist and forearm motions [17]

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[Abstract] Control and Dynamic Manipulability of a Dual-Arm/Hand Robotic Exoskeleton System (EXO-UL8) for Rehabilitation Training in Virtual Reality

Author & Article Info

Every year there are about 800,000 new stroke patients in the US, and many of them suffer from upper limb neuromuscular disabilities including but not limited to: weakness, spasticity and abnormal synergy. Patients usually have the potential to rehabilitate (to some extent) based on neuroplasticity, and physical therapy intervention helps accelerate the recovery. However, many patients could not afford the expensive physical therapy after the onset of stroke, and miss the opportunity to get recovered. Robot-assisted rehabilitation thus might be the solution, with the following unparalleled advantages:

  1. 24/7 capability of human arm gravity compensation;
  2. multi-joint movement coordination/correction, which could not be easily done by human physical therapists;
  3. dual-arm training, either coupled in joint space or task space;
  4. quantitative platform for giving instructions, providing assistance, exerting resistance, and collecting real-time data in kinematics, dynamics and biomechanics;
  5. potential training protocol personalization; etc.

However, in the rehabilitation robotics field, there are still many open problems. I am especially interested in:

  1. compliant control, in high-dimensional multi-joint coordination condition;
  2. assist-as-needed (AAN) control, in quantitative model-based approach and model-free approach;
  3. dual-arm training, in both symmetric and asymmetric modes;
  4. system integration, e.g., virtual reality (VR) serious games and graphical user interfaces (GUIs) design and development.

Our dual-arm/hand robotic exoskeleton system, EXO-UL8, is in its 4th generation, with seven (7) arm degrees-of-freedom (DOFs) and one (1) DOF hand gripper enabling hand opening and closing on each side. While developing features on this research platform, I contributed to the robotics research field in the following aspects:

(1) I designed and developed a series of eighteen (18) serious VR games and GUIs that could be used for interactive post-stroke rehabilitation training. The VR environment, together with the exoskeleton robot, provides patients and physical therapists a quantitative rehabilitation training platform with capability in real-time human performance data collection and analysis.

(2) To provide better compliant control, my colleagues and I proposed and implemented two new admittance controllers, based on the work done by previous research group alumni. Both the hyper parameter-based and Kalman Filter-based admittance controllers have satisfactory heuristic performance, and the latter is more promising in future adaptation. Unlike many other upper-limb exoskeletons, our current system utilizes force and torque (F/T) sensors and position encoders only, no surface electromyography (sEMG) signals are used. It brings convenience to practical use, as well as technical challenges.

(3) To provide better AAN control, which is still not well understood in the academia, I worked out a redundant version of modified dynamic manipulability ellipsoid (DME) model to propose an Arm Postural Stability Index (APSI) to quantify the difficulty heterogeneity of the 3D Cartesian workspace. The theoretical framework could be used to teach the exoskeleton where and when to provide assistance, and to guide the virtual reality where to add new minimal challenges to stroke patients. To the best of my knowledge, it is also for the first time that human arm redundancy resolution was investigated when arm gravity is considered.

(4) For the first time, my colleagues and I have done a pilot study on asymmetric dual-arm training using the exoskeleton system on one (1) post-stroke patient. The exoskeleton on the healthy side could trigger assistance for that on the affected side, and validates that the current mechanism/control is eligible for asymmetric dual-arm training.

(5) Other works of mine include: activities of daily living (ADLs) data visualization for VR game difficulty design; human arm synergy modeling; dual-arm manipulation taxonomy classification (on-going work).

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[ARTICLE] Robotics for rehabilitation of hand movement in stroke survivors – Full Text

This article aims to give an overall review of research status in hand rehabilitation robotic technology, evaluating a number of devices. The main scope is to explore the current state of art to help and support designers and clinicians make better choices among varied devices and components. The review also focuses on both mechanical design, usability and training paradigms since these parts are interconnected for an effective hand recovery. In order to study the rehabilitation robotic technology status, the devices have been divided in two categories: end-effector robots and exoskeleton devices. The end-effector robots are more flexible than exoskeleton devices in fitting the different size of hands, reducing the setup time and increasing the usability for new patients. They suffer from the control of distal joints and haptic aspects of object manipulation. In this way, exoskeleton devices may represent a new opportunity. Nevertheless their design is complex and a deep investigation of hand biomechanics and physical human–robot interaction is required. The main hand exoskeletons have been developed in the last decade and the results are promising demonstrated by the growth of the commercialized devices. Finally, a discussion on the complexity to define which design is better and more effective than the other one is summarized for future investigations.

Over the past years, rehabilitation engineering has played a crucial role in improving the hand and finger function after stroke. The applications of robotics and mechatronic devices have rapidly expanded from the industrial environment to human assistance in rehabilitation and functional improvements. Rehabilitation engineering has increased the quality lives of individuals with disabilities, offering dedicated training that performs better than conventional methods.

In this way, there are many challenges and opportunities to integrate engineering concepts into hand rehabilitation, and increasing population wellbeing and wealth as well as reducing healthcare costs. This motivates researchers to study, design, and develop novel rehabilitative and assistive technologies and devices to help people to motor functions. Specifically, the current challenge is to transfer the research results and new knowledge to stakeholders creating a general awareness of the importance of rehabilitation engineering.

This review aims to present and discuss the main robotic technologies for hand recovery rehabilitation in stroke survivors, evaluating and comparing previous and current works and researches. This study explores the current state of art to help and support designers and clinicians make better choices among varied devices and components. The review also focuses on both mechanical design (e.g. concept), usability (e.g. setup, lightness, portability) and training paradigms (e.g. hand, hand/wrist or entire arm) since these parts are interconnected for an effective hand recovery. An overview of the main advantages and drawbacks in applying robotics to hand motor impairments is provided in order to give a general view of the relationship between hand rehabilitation devices, rehabilitation theories and results. The challenge is to restore the hand movements such as opening, closing, grasping and releasing movements. Second, a discussion on the application and new challenges of rehabilitation robotic devices is summarized for future investigations. In particular, the main challenges are to develop safe devices with less complex designs, increasing potential for portability and efficacy. In fact, future development for patient treatment should include the device portability to increase the potential applications. The preliminary results have highlighted the robot-assisted therapy currently works hand in hand rather than a replacement of traditional therapy. Therapies and rehabilitation strategies should be not only more effective but also more cost-efficient.

Stroke is one of the leading causes of long-term disability, affecting approximately 14% of world’s population.1,2 33% of survivors reports very limited or no functional use of the upper limb.3 Rehabilitation activities based on repeated exercises have been identified suitable in recovering some degree of motion, in particular, a simple flexion and extension of fingers has demonstrated improvements in hand functionality.4,5 In this way, medical devices and robot-assisted strategies may provide a number of advantages guaranteeing the range of motion (ROM) and avoiding inappropriate movements. Nevertheless, only a limited part of the proposed devices by the literature has been clinically tested, highlighting as the design complexity and development costs may negatively impact the system implementation. The previous and current robots and devices are often too complex to be used by patients limiting any testing on the real users.

Note that the hand functional improvement may be the result of a set of compensatory strategies based on an initial support assisted by the physiotherapist. Usually, these approaches may be suggested during the first months after stroke, when the impairment reduction may be preferred to extensive functional training. In this phase of impairment, the patients show a loss of control and a decreased tactile sensation and proprioception, reducing the physical independence and social integration. The patient’s motivation associated with verbal encouragement may significantly impact the therapy efficacy.

Over the last decades, a set of studies has evaluated the influence of the robot-assisted therapies on arm motor improvement and impairment reduction using randomized clinical controlled trials.612 The obtained results have not shown a complete consensus; nevertheless, the therapy assisted by robotics seems to obtain results beyond what is done by conventional methods.1317 In particular, researchers have been slow to investigate the hand function due to the complexity of this limb.11,12,1820

In any case, a number of studies observed that the rehabilitation training can improve the hand motor in terms of pull, push, and grip strengths, confirming that robotic training is at least as effective as conventional training.13,2124 A significant part of the obtained outcomes have been also proved by Fugl-Meyer Assessment (FMA) and Functional Independence Measure (FIM) tests, performed after the robot treatment.2527

Despite these promising results, the literature review shows also researches that did not observed significant difference between conventional and robotic training groups, highlighting as the conventional therapies are more effective in decreasing levels of impairment and disability.2,8,28,29 Mazzoleni et al.29 and Colombo et al.30 have underlined that there are other significant factors that may impact the efficacy of the training outcome, such as recovery stage, intensity, or duration of the rehabilitation therapy. This point needs to be considered to evaluate and compare different therapy treatments. In the light of these considerations, there are not evident conclusions that sustain the robot-therapy efficacy, suggesting further investigations.31,32

 

Robot-based methods may be used independently by patients in different levels of impairment. Robots permit to obtain a quantifiable measure of subjective performance, repeating treatment protocols without the need of continuous involvement of therapists saving a significant amount of the human labor that may lead to high cost.8,10 In fact, traditional therapist–based methods require several sessions of rehabilitation training, inducing impractical and unaffordable therapies for many patients. Robotic therapy techniques guarantee a safe, intensive, and task-oriented rehabilitation at relatively moderate costs.14,1533 They may apply forces with precision, improving accuracy and reducing variance. These actions are potentially effective to strengthen muscle, ROM, and motor coordination. Advanced robots provide also tactile feedback that may correct the impaired movements. In addition, robot-assisted therapies may be quantified easily and collect a number of parameters useful to track the patient’s status (e.g. spasticity or level of voluntary control).34

A further advantage of robotic rehabilitation consists of the possibility to be combined with other technologies (e.g. virtual reality (VR), brain computer interface (BCI) technology or haptic stimuli).3537 This combination allows to motivate the patients to perform the rehabilitation tasks without the constant supervision, guaranteeing repetitive movements and informative feedback. On the other hand, robot-assisted therapy permits the therapist to conduct rehabilitation tasks for two or more patients at the same time, improving the service efficiency.

Finally, it has been noted that robotics may improve the accessibility to rehabilitation. In fact, a patient prefers to use the unaffected limb in daily activities, damaging the recovery of the impaired limb.38 The possibility to perform rehabilitation in remote locations (e.g. home) using robotics devices may involve better the patient in the recovery process.

Despite these noted advantages, a number of limits and constraints of rehabilitation robot-based cannot be ignored. First, there is a significant gap between the outcomes of rehabilitation robots and people’s expectations. This element may negatively impact patient’s motivations during the therapy. In particular, the personalization is still difficult due to the design complexity of devices. Another further issue is the determination of the most efficient dosage of rehabilitation training.

Although the literature has demonstrated the main advantages and benefits of robot applications, more studies involving a large participant size are required to confirm whether robotic-assisted therapy performs better than conventional methods, evaluating and comparing the treatment dosage. In particular, a lack of robust methods to evaluate the efficacy of the robot-assisted therapy making difficult to define which design is better and more effective than the other one. A deep investigation is needed to explore whether the obtained results on the patient can be maintained in the long term and how the potential improvements can be transformed into the motor skills in performing the activities of daily living (ADL). The user’s safety needs to be guaranteed during the training, avoiding the nonlinear movement of the patient. Further limits are noted on the current robotic devices regarding their design, often complex and unconvinced for the user, or the high costs for the treatment access.3941 The ratio between the price and performance is rather dissatisfactory due to the high cost of development combined with a relatively benefit for patients and clinics.4244 These drawbacks need to be considered in the overall evaluation of robotic application. They represent an open challenge to improve the integration of engineering concepts into hand rehabilitation, increasing population wealth, as well as reducing healthcare costs. These issues justify the low penetration of robotics in the market and the requirements of new investigations. Only a limited number of stroke patients (5%–15%) who requires assistive devices and technologies may access to this service. On the other hand, the studies and researches on rehabilitation robots are becoming strategic for the society due to the fact that the costs of excluding people with disabilities are high and borne by community.45

A primary categorization of rehabilitation robotic technologies is based on the design concepts of the device: end-effector or exoskeleton.

An end-effector device (also called endpoint control) recreates dynamic environments corresponding to ADL, determining the movements at the joint level. Usually, the patient’s joint rotation is distally executed using a support (e.g. a table or a tripod) to facilitate the training and avoiding muscle fatigue. It means that the more proximal joints are not directly controlled by the robot. End-effector devices may be dedicated to hand rehabilitation or to be integrated in more complex structures for the arm recovery.

The second main logic to design a rehabilitation robotic device is the exoskeleton. An exoskeleton, from Greek “exo” = outer and “skeletos” = skeleton, is a wearable robot attached to the user’s limbs, in order to enhance their movements. It focuses on the anatomy of the subject’s hand following the limb segments, each degree of freedom is aligned with the corresponding human joint. Figure 1 illustrates a number of examples. An exoskeleton should be compliant with the user’s movements and delivers at least part of the power required by the movements. In order to guarantee the natural motor of the hand joints, their design is more complex than end-effector devices. For example, a set of components (e.g. rings, hinges, external linkages, or structures) is embedded to accomplish the alignment between the forearm axial rotation of the forearm located along an axis between the ulna and the radius50,51 to support in forearm pronation and supination.

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Figure 1. Examples of rehabilitation robotic devices: (a) Gloreha,46 (b) CyberGrasp,47 (c) Hand of Hope,48 and (d) Reha-Digit.49

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Continue —> Robotics for rehabilitation of hand movement in stroke survivors – Francesco Aggogeri, Tadeusz Mikolajczyk, James O’Kane, 2019

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