Posts Tagged Exoskeleton

[REVIEW] Robotic Devices and Brain Machine Interfaces for Hand Rehabilitation Post-stroke: Current State and Future Potentials – Full Text PDF

Abstract

This paper reviews the current state of the art in robotic-aided hand physiotherapy for post-stroke rehabilitation, including the use of brain machine interfaces (BMI). The main focus is on the technical specifications required for these devices to achieve their goals. From the literature reviewed, it is clear that these rehabilitation devices can increase the functionality of the human hand post-stroke. However, there are still several challenges to be overcome before they can be fully deployed. Further clinical trials are needed to ensure that substantial improvement can be made in limb functionality for stroke survivors, particularly as part of a programme of frequent at-home high-intensity training over an extended period.

This review serves the purpose of providing valuable insights into robotics rehabilitation techniques in particular for those that could explore the synergy between BMI and the novel area of soft robotics.

Introduction

Strokes are a global issue affecting people of all ethnicities, genders and ages [1]; approximately 20 million people per year worldwide suffer a stroke [2, 3]. Five million of those patients remain severely handicapped and dependent on assistance in daily life [4]. Once a stroke has occurred the patient may be left with mild to severe disabilities, depending on the type and severity of the stroke. This paper will focus on the primary issues experienced which are the clawing of the hand and stiffening of the wrist. In recent years, several new forms of rehabilitation have been proposed using robot-aided therapy. This work reviews the current state-ofthe-art robotic devices and brain-machine interfaces (BMI) for post-stroke hand rehabilitation, analysing current challenges, highlighting the future potential and addressing any inherent ethical issues.[…]

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[ARTICLE] Hemorrhagic versus ischemic stroke: Who can best benefit from blended conventional physiotherapy with robotic-assisted gait therapy? – Full Text

Abstract

Background

Contrary to common belief of clinicians that hemorrhagic stroke survivors have better functional prognoses than ischemic, recent studies show that ischemic survivors could experience similar or even better functional improvements. However, the influence of stroke subtype on gait and posture outcomes following an intervention blending conventional physiotherapy with robotic-assisted gait therapy is missing.

Objective

This study compared gait and posture outcome measures between ambulatory hemorrhagic patients and ischemic patients, who received a similar 4 weeks’ intervention blending a conventional bottom-up physiotherapy approach and an exoskeleton top-down robotic-assisted gait training (RAGT) approach with Lokomat.

Methods

Forty adult hemiparetic stroke inpatient subjects were recruited: 20 hemorrhagic and 20 ischemic, matched by age, gender, side of hemisphere lesion, stroke severity, and locomotor impairments. Functional Ambulation Category, Postural Assessment Scale for Stroke, Tinetti Performance Oriented Mobility Assessment, 6 Minutes Walk Test, Timed Up and Go and 10-Meter Walk Test were performed before and after a 4-week long intervention. Functional gains were calculated for all tests.

Results

Hemorrhagic and ischemic subjects showed significant improvements in Functional Ambulation Category (P<0.001 and P = 0.008, respectively), Postural Assessment Scale for Stroke (P<0.001 and P = 0.003), 6 Minutes Walk Test (P = 0.003 and P = 0.015) and 10-Meter Walk Test (P = 0.001 and P = 0.024). Ischemic patients also showed significant improvements in Timed Up and Go. Significantly greater mean Functional Ambulation Category and Tinetti Performance Oriented Mobility Assessment gains were observed for hemorrhagic compared to ischemic, with large (dz = 0.81) and medium (dz = 0.66) effect sizes, respectively.

Conclusion

Overall, both groups exhibited quasi similar functional improvements and benefits from the same type, length and frequency of blended conventional physiotherapy and RAGT protocol. The use of intensive treatment plans blending top-down physiotherapy and bottom-up robotic approaches is promising for post-stroke rehabilitation.

Continue —>  Hemorrhagic versus ischemic stroke: Who can best benefit from blended conventional physiotherapy with robotic-assisted gait therapy?

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[VIDEO] Fourier X1 Exoskeleton – Fourier Intelligence – YouTube

Δημοσιεύτηκε στις 23 Μαρ 2017

At Fourier Intelligence, we do not believe these people are fated to sit on the wheelchair in their rest life. To let them stand up, and to allow them to walk again, we started to develop a genuinely new exoskeleton products- The Fourier X1

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[ARTICLE] A wearable exoskeleton suit for motion assistance to paralysed patients – Full Text

Summary

Background/Objective

The number of patients paralysed due to stroke, spinal cord injury, or other related diseases is increasing. In order to improve the physical and mental health of these patients, robotic devices that can help them to regain the mobility to stand and walk are highly desirable. The aim of this study is to develop a wearable exoskeleton suit to help paralysed patients regain the ability to stand up/sit down (STS) and walk.

Methods

A lower extremity exoskeleton named CUHK-EXO was developed with considerations of ergonomics, user-friendly interface, safety, and comfort. The mechanical structure, human-machine interface, reference trajectories of the exoskeleton hip and knee joints, and control architecture of CUHK-EXO were designed. Clinical trials with a paralysed patient were performed to validate the effectiveness of the whole system design.

Results

With the assistance provided by CUHK-EXO, the paralysed patient was able to STS and walk. As designed, the actual joint angles of the exoskeleton well followed the designed reference trajectories, and assistive torques generated from the exoskeleton actuators were able to support the patient’s STS and walking motions.

Conclusion

The whole system design of CUHK-EXO is effective and can be optimised for clinical application. The exoskeleton can provide proper assistance in enabling paralysed patients to STS and walk.

Continue —> A wearable exoskeleton suit for motion assistance to paralysed patients

 

Figure 1

Figure 1. The wearable exoskeleton suit CUHK-EXO. (A) A patient with the wearable exoskeleton suit CUHK-EXO supported by a pair of smart crutches; (B) diagram of the overall mechanical structure of CUHK-EXO; (C) waist structure of CUHK-EXO; (D) thigh structure of CUHK-EXO; (E) shank structure of CUHK-EXO. (F) foot structure of CUHK-EXO.

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[WEB SITE] One step at a time

IMAGE: DR. KIM (LEFT) WITH DR. SHARMA AND A HYBRID EXOSKELETON PROTOTYPE IN THE NEUROMUSCULAR CONTROL AND ROBOTICS LABORATORY IN THE SWANSON SCHOOL OF ENGINEERING. view more CREDIT: SWANSON SCHOOL OF ENGINEERING

PITTSBURGH (March 7, 2017) … The promise of exoskeleton technology that would allow individuals with motor impairment to walk has been a challenge for decades. A major difficulty to overcome is that even though a patient is unable to control leg muscles, a powered exoskeleton could still cause muscle fatigue and potential injury.

However, an award from the National Science Foundation’s Cyber-Physical Systems (CPS) program will enable researchers at the University of Pittsburgh to develop an ultrasound sensor system at the heart of a hybrid exoskeleton that utilizes both electrical nerve stimulation and external motors.

Principal investigator of the three year, $400,000 award is Nitin Sharma, assistant professor of mechanical engineering and materials science at Pitt’s Swanson School of Engineering. Co-PI is Kang Kim, associate professor of medicine and bioengineering. The Pitt team is collaborating with researchers led by Siddhartha Sikdar, associate professor of bioengineering and electrical and computer engineering at George Mason University, who also received a $400,000 award for the CPS proposal, “Synergy: Collaborative Research: Closed-loop Hybrid Exoskeleton utilizing Wearable Ultrasound Imaging Sensors for Measuring Fatigue.”

This latest funding furthers Dr. Sharma’s development of hybrid exoskeletons that combine functional electrical stimulation (FES), which uses low-level electrical currents to activate leg muscles, with powered exoskeletons, which use electric motors mounted on an external frame to move the wearer’s joints.

“One of the most serious impediments to developing a human exoskeleton is determining how a person who has lost gait function knows whether his or her muscles are fatigued. An exoskeleton has no interface with a human neuromuscular system, and the patient doesn’t necessarily know if the leg muscles are tired, and that can lead to injury,” Dr. Sharma explained. “Electromyography (EMG), the current method to measure muscle fatigue, is not reliable because there is a great deal of electrical “cross-talk” between muscles and so differentiating signals in the forearm or thigh is a challenge.”

To overcome the low signal-to-noise ratio of traditional EMG, Dr. Sharma partnered with Dr. Kim, whose research in ultrasound focuses on analyzing muscle fatigue.

“An exoskeleton biosensor needs to be noninvasive, but systems like EMG aren’t sensitive enough to distinguish signals in complex muscle groups,” Dr. Kim said. “Ultrasound provides image-based, real-time sensing of complex physical phenomena like neuromuscular activity and fatigue. This allows Nitin’s hybrid exoskeleton to switch between joint actuators and FES, depending upon the patient’s muscle fatigue.”

In addition to mating Dr. Sharma’s hybrid exoskeleton to Dr. Kim’s ultrasound sensors, the research group will develop computational algorithms for real-time sensing of muscle function and fatigue. Human subjects using a leg-extension machine will enable detailed measurement of strain rates, transition to fatigue, and full fatigue to create a novel muscle-fatigue prediction model. Future phases will allow the Pitt and George Mason researchers to develop a wearable device for patients with motor impairment.

“Right now an exoskeleton combined with ultrasound sensors is just a big machine, and you don’t want to weigh down a patient with a backpack of computer systems and batteries,” Dr. Sharma said. “The translational research with George Mason will enable us to integrate a wearable ultrasound sensor with a hybrid exoskeleton, and develop a fully functional system that will aid in rehabilitation and mobility for individuals who have suffered spinal cord injuries or strokes.”

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Source: One step at a time | EurekAlert! Science News

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[ARTICLE] The Efficacy of State of the Art Overground Gait Rehabilitation Robotics: A Bird’s Eye View – Full Text

Abstract

To date, rehabilitation robotics has come a long way effectively aiding the rehabilitation process of the patients suffering from paraplegia or hemiplegia due to spinal cord injury (SCI) or stroke respectively, through partial or even full functional recovery of the affected limb. The increased therapeutic outcome primarily results from a combination of increased patient independence and as well as reduced physical burden on the therapist. Especially for the case of gait rehabilitation following SCI or stroke, the rehab robots have the potential to significantly increase the independence of the patient during the rehabilitation process without the patient’s safety being compromised. An intensive gait-oriented rehabilitation therapy is often effective irrespective of the type of rehabilitation paradigm. However, eventually overground gait training, in comparison with body-weight supported treadmill training (BWSTT), has the potential of higher therapeutic outcome due its associated biomechanics being very close to that of the natural gait. Recognizing the apparent superiority of the overground gait training paradigms, a through literature survey on all the major overground robotic gait rehabilitation approaches was carried out and is presented in this paper. The survey includes an in-depth comparative study amongst these robotic approaches in terms of gait rehabilitation efficacy.

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Source: The Efficacy of State of the Art Overground Gait Rehabilitation Robotics: A Bird’s Eye View

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[ARTICLE] Weight compensation characteristics of Armeo®Spring exoskeleton: implications for clinical practice and research – Full Text

Abstract

Background

Armeo®Spring exoskeleton is widely used for upper extremity rehabilitation; however, weight compensation provided by the device appears insufficiently characterized to fully utilize it in clinical and research settings.

Methods

Weight compensation was quantified by measuring static force in the sagittal plane with a load cell attached to the elbow joint of Armeo®Spring. All upper spring settings were examined in 5° increments at the minimum, maximum, and two intermediate upper and lower module length settings, while keeping the lower spring at minimum. The same measurements were made for minimum upper spring setting and maximum lower spring setting at minimum and maximum module lengths. Weight compensation was plotted against upper module angles, and slope was analyzed for each condition.

Results

The Armeo®Spring design prompted defining the slack angle and exoskeleton balance angle, which, depending on spring and length settings, divide the operating range into different unloading and loading regions. Higher spring tensions and shorter module lengths provided greater unloading (≤6.32 kg of support). Weight compensation slope decreased faster with shorter length settings (minimum length = −0.082 ± 0.002 kg/°; maximum length = −0.046 ± 0.001 kg/°) independent of spring settings.

Conclusions

Understanding the impact of different settings on the Armeo®Spring weight compensation should help define best clinical practice and improve fidelity of research.

Continue —> Weight compensation characteristics of Armeo®Spring exoskeleton: implications for clinical practice and research | Journal of NeuroEngineering and Rehabilitation | Full Text

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[ARTICLE] Development and assessment of a hand assist device: GRIPIT – Full Text

Abstract

Background

Although various hand assist devices have been commercialized for people with paralysis, they are somewhat limited in terms of tool fixation and device attachment method. Hand exoskeleton robots allow users to grasp a wider range of tools but are heavy, complicated, and bulky owing to the presence of numerous actuators and controllers. The GRIPIT hand assist device overcomes the limitations of both conventional devices and exoskeleton robots by providing improved tool fixation and device attachment in a lightweight and compact device. GRIPIT has been designed to assist tripod grasp for people with spinal cord injury because this grasp posture is frequently used in school and offices for such activities as writing and grasping small objects.

Methods

The main development objective of GRIPIT is to assist users to grasp tools with their own hand using a lightweight, compact assistive device that is manually operated via a single wire. GRIPIT consists of only a glove, a wire, and a small structure that maintains tendon tension to permit a stable grasp. The tendon routing points are designed to apply force to the thumb, index finger, and middle finger to form a tripod grasp. A tension-maintenance structure sustains the grasp posture with appropriate tension. Following device development, four people with spinal cord injury were recruited to verify the writing performance of GRIPIT compared to the performance of a conventional penholder and handwriting. Writing was chosen as the assessment task because it requires a tripod grasp, which is one of the main performance objectives of GRIPIT.

Results

New assessment, which includes six different writing tasks, was devised to measure writing ability from various viewpoints including both qualitative and quantitative methods, while most conventional assessments include only qualitative methods or simple time measuring assessments. Appearance, portability, difficulty of wearing, difficulty of grasping the subject, writing sensation, fatigability, and legibility were measured to assess qualitative performance while writing various words and sentences. Results showed that GRIPIT is relatively complicated to wear and use compared to a conventional assist device but has advantages for writing sensation, fatigability, and legibility because it affords sufficient grasp force during writing. Two quantitative performance factors were assessed, accuracy of writing and solidity of writing. To assess accuracy of writing, we asked subjects to draw various figures under given conditions. To assess solidity of writing, pen tip force and the angle variation of the pen were measured. Quantitative evaluation results showed that GRIPIT helps users to write accurately without pen shakes even high force is applied on the pen.

Conclusions

Qualitative and quantitative results were better when subjects used GRIPIT than when they used the conventional penholder, mainly because GRIPIT allowed them to exert a higher grasp force. Grasp force is important because disabled people cannot control their fingers and thus need to move their entire arm to write, while non-disabled people only need to move their fingers to write. The tension-maintenance structure developed for GRIPIT provides appropriate grasp force and moment balance on the user’s hand, but the other writing method only fixes the pen using friction force or requires the user’s arm to generate a grasp force.

Background

The hand is one of the most essential body parts for independent living because so many tasks of daily life, such as writing, eating, and grasping, require a functional hand. People who suffer from permanent paralysis of the hand owing to cerebral palsy, spinal cord injury (SCI), stroke, and other neurological disorders require assistive or rehabilitation devices in order to regain independence and return to work [1, 2].

A selection of commercialized hand assist devices is shown in Fig. 1. These devices are attached to the user’s arm or hand with Velcro® or elastic bands, and hand tools such as pens, forks, and paintbrushes are clamped into a hole in the devices. One drawback of these devices is that they can only grasp one type of tool because the receiving hole is a constant size. Users also must sometimes sustain an awkward posture to use a tool because it is mounted into the device in an unfamiliar position. Additionally, the Velcro or elastic band used to fix the device can apply high pressure to the skin if the strapping is too tight, and tools can be too shaky to use if the strapping becomes too loose. These problems reduce the usability of these devices and require users to put in a certain of amount of training time to become familiar with their use.

Fig. 1 Various types of hand assist devices for people with hand paralysis. a Writing aid. b Eating aid. c Grasping aid. d Cooking aid

Continue —> Development and assessment of a hand assist device: GRIPIT | Journal of NeuroEngineering and Rehabilitation | Full Text

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[BLOG POST] Superflex: Soft Exoskeleton For Elderly That Can Be Worn Like Underwear.

FEBRUARY 6, 2017

Photo of the back of an elderly person with wavy white hair. She is seen wearing a soft exoskeleton and holding both her arms.

One third of adults over 65 report difficulty walking three blocks. Mobility is a serious concern for the aging population which stems from the fact that other physical ailments and issues force them to stay at home, leading to loss of freedom, increased depression, and risks of getting other diseases like diabetes.

To cater to that population, SRI International is designing an exoskeleton that can be worn like an undergarment. This soft exoskeleton, weighing four pounds, wraps around the user’s core, and provides another set of mechanical muscles that can help elderly sit, stand, and even walk. An in built computer makes sure that the flexing happens along with the real muscles to supplement the energy generated by them. The first version of this suit may require it to be charged once a day.

diagram showing how super flex fits the body.  It covers the chest and torso and goes down till the knees. this photo has two bodies - one male and other female.

The “powered suit” (called Superflex) is designed not just to provide convenience but comfort as well. Rich Mahoney, the CEO, has hired a team of textile and fashion designers to ensure that this suit is worn easily, looks attractive & feels comfortable, and also lets the person use bathroom with ease.

This suit can be used not just by elderly people who complain of a sedentary lifestyle but also by people who have injuries and are in rehabilitation. Superflex is targeting to launch sometime in Mid 2018. Although there is no information on price, the company says that it will be affordable, and people interested in it wouldn’t have to depend on insurance subsidies.

Source: Fast Co Design

Source: Superflex: Soft Exoskeleton For Elderly That Can Be Worn Like Underwear – Assistive Technology Blog

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[WEB PAGE] ‘Knitted muscles’ provide power

January 25, 2017
'Knitted muscles' provide power

Conceptual model of a textile exoskeleton with the textile actuator (black) on an elastic elbow sleeve (white). Credit: Thor Balkhed/Linköping University

Researchers have coated normal fabric with an electroactive material, and in this way given it the ability to actuate in the same way as muscle fibres. The technology opens new opportunities to design “textile muscles” that could, for example, be incorporated into clothes, making it easier for people with disabilities to move. The study, which has been carried out by researchers at Linköping University and the University of Borås in Sweden, has been published in Science Advances.

Developments in robot technology and prostheses have been rapid, due to technological breakthroughs. For example, devices known as “” that act as an external skeleton and muscles have been developed to reinforce a person’s own mobility.

“Enormous and impressive advances have been made in the development of exoskeletons, which now enable people with disabilities to walk again. But the existing technology looks like rigid robotic suits. It is our dream to create exoskeletons that are similar to items of clothing, such as “running tights” that you can wear under your normal clothes. Such device could make it easier for older persons and those with impaired mobility to walk,” says Edwin Jager, associate professor at Division of Sensor and Actuator Systems, Linköping University.

Current exoskeletons are driven by motors or pressurised air and develop power in this way. In the new study, the researchers have instead used the advantages provided by lightweight and flexible fabrics, and developed what can be described as “textile muscles”. The researchers have used mass-producible fabric and coated it with an electroactive material. It is in this special coating that the force in the textile muscles arises. A low voltage applied to the fabric causes the electroactive material to change volume, causing the yarn or fibres to increase in length. The properties of the textile are controlled by its woven or knitted structure. Researchers can exploit this principle, depending on how the textile is to be used.

'Knitted muscles' provide power

A photograph of a knitted textile actuator (or textile muscle) including the electrical and mechanical contacts made of copper tape. Credit: Thor Balkhed/Linköping University

“If we weave the fabric, for example, we can design it to produce a high force. In this case, the extension of the fabric is the same as that of the individual threads. But what happens is that the force developed is much higher when the threads are connected in parallel in the weave. This is the same as in our muscles. Alternatively, we can use an extremely stretchable knitted structure in order to increase the effective extension,” says Nils-Krister Persson, associate professor in the Smart Textiles Initiative at the Swedish School of Textiles, University of Borås.

The researchers show in the article that the textile muscles can be used in a simple robot device to lift a small weight. They demonstrate that the technology enables new ways to design and manufacture devices known as “actuators”, which – like motors and biological muscles – can exert a force.

'Knitted muscles' provide power

From left to right: A single yarn coated with the electroactive polymer (polypyrrole); a knitted textile actuator (or textile muscle) including the electrical and mechanical contacts made of copper tape; and a piece of knitwear coated with the electroactive polymer (polypyrrole). Credit: Thor Balkhed/Linköping University

“Our approach may make it possible in the long term to manufacture actuators in a simple way and hopefully at a reasonable cost by using already existing textile production technologies. What’s more interesting, however, is that it may open completely new applications in the future, such as integrating textile muscles into items of clothing,” says Edwin Jager.

'Knitted muscles' provide power

Photo of the knitted textile actuator mounted in the force measurement setup. On the top the actuator is mounted to the lever arm of the force sensor using a small electrically insulated hook. On the bottom it is both electrically and mechanically connected in a beaker that contains the liquid electrolyte. A second, auxiliary electrode (the piece of gold coated plastic) is also inserted in the container to close the electrical circuit. Credit: Thor Balkhed/Linköping University

Explore further: ‘Space cloth’ to revolutionise textiles industry

More information: “Knitting and weaving artificial muscles,” Science Advances, DOI: 10.1126/sciadv.1600327 , http://advances.sciencemag.org/content/3/1/e1600327

Source: ‘Knitted muscles’ provide power

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