Posts Tagged Exoskeleton

[Abstract + References] A New Approach to Design Glove-Like Wearable Hand Exoskeletons for Rehabilitation – Conference paper

Abstract

The synthesis of hand exoskeletons for rehabilitation is a challenging theoretical and technical task. A huge number of solutions have been proposed in the literature. Most of them are based on the concept to consider the phalanges of the finger as fixed to some links of the exoskeleton mechanism. This approach makes the exoskeleton synthesis a difficult problem that compels the designer to devise approximate technical solutions which, frequently, reduce the efficiency of the rehabilitation system and are rather bulky.

This paper proposes a different approach. Namely, the phalanges are not fixed to some links of the exoskeleton, but they can have a relative motion, with one or two degrees of freedom when planar systems are considered. An example is presented to show the potentiality of this approach, which makes it possible: (i) to design glove-like exoskeletons that only approximate the human finger motion; (ii) to leave the fingers have their natural motion; (iii) to adapt a wider range of patient hand sizes to a given hand exoskeleton.

References

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    Agarwal, P., Hechanova, A., Deshpande, A.D.: Kinematics and Dynamics of a biologically inspired index finger exoskeleton. In: Proceedings of the ASME 2013 Dynamic Systems and Control Conference DSCC 2013, Palo Alto, CA, USA, pp. 1–10 (2013)Google Scholar
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    Heo, P., Min, GuG, Lee, S.J., Rhee, K., Kim, J.: Current hand exoskeleton technologies for rehabilitation and assistive engineering. Int. J. Precis. Eng. Manuf. 3(5), 807–824 (2012)CrossRefGoogle Scholar
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    Balasubramanian, S., Klein, J., Burdet, E.: Robot-assisted rehabilitation and hand function. Curr. Opin. Neurol. 23, 661–670 (2010)CrossRefGoogle Scholar
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    Troncossi, M., Mozaffari-Foumashi, M., Parenti-Castelli, V.: An original classification of rehabilitation hand exoskeletons. J. Robot. Mech. Eng. Res. 1(4), 17–29 (2016)CrossRefGoogle Scholar
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    Abdallah, I.B., Bouteraa, Y., Rekik, C.: Design and development of 3D printed myoelectric robotic exoskeleton for hand rehabilitation. Int. J. Smart Sens. Intell. Syst. 10(2), 341–366 (2017)Google Scholar
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    Foumashi, M., Troncossi, M., Parenti-Castelli, V.: Design of a new hand exo-skeleton for rehabilitation of post-stroke patients. In: Romansy 19-Robot Design, Dynamics and Control, pp. 159–169 (2013)CrossRefGoogle Scholar
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    Yap, H.K., Hoon, J., Nashrallah, F., Goh, J.C.H., Yeow, R.C.H.: A soft exoskeleton for hand assistive and rehabilitation application using pneumatic actuators with variable stiffness. In: 2015 IEEE International Conference on Robotics and Automation, ICRA, Seattle, Washington, USA, pp. 4967–4972 (2015)Google Scholar
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    Arata, J., Ohmoto, K., Gassert, R., Lambercy, O., Fujimoto, H., Wada, I.: A new hand exoskeleton device for rehabilitation using a three-layered sliding spring mechanism. In: 2013 IEEE International Conference on Robotics and Automation, ICRA, Karlsruhe, Germany, pp. 3902–3907 (2013)Google Scholar
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    Leonardis, D., Barsotti, M., Loconsole, C., Solazzi, M., Troncossi, M., Mazzotti, M., Parenti, C.V., Procopio, C., Lamola, G., Chisari, C., Bergamasco, M., Frisoli, A.: An EMG-controlled robotic hand exoskeleton for bilateral rehabilitation. J. Haptics 8(2), 140–151 (2015)CrossRefGoogle Scholar
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    Gulke, J., Watcher, N.J., Geyer, T., Scholl, H., Apic, G., Mentzler, M., et al.: Motion coordination pattern during cylinder grip analyzed with a sensor glove. J. Hand Surg. 35(5), 797 (2010)CrossRefGoogle Scholar
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    Li, J., Wang, S., Zheng, R., Zhang, Y., Chen, Z.: Development of a hand exoskeleton system for index finger rehabilitation. Chin. J. Mech. Eng. 25(2), 223–233 (2012)CrossRefGoogle Scholar

via A New Approach to Design Glove-Like Wearable Hand Exoskeletons for Rehabilitation | SpringerLink

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[Abstract] Adaptive integral terminal sliding mode control for upper-limb rehabilitation exoskeleton

Highlights

    Adaptive integral sliding mode control design for exoskeletons.

    Finite time convergence of the closed-loop system.

    Robustness of the control law with respect to parametric variations and disturbances.

    No requirement of the knowledge of the system bounds.

    Real experiments using an upper limb exoskeleton with and without human subjects.

Abstract

A robust adaptive integral terminal sliding mode control strategy is proposed in this paper to deal with unknown but bounded dynamic uncertainties of a nonlinear system. This method is applied for the control of upper limb exoskeleton in order to achieve passive rehabilitation movements. Indeed, exoskeletons are in direct interaction with the human limb and even if it is possible to identify the nominal dynamics of the exoskeleton, the subject’s limb dynamics remain typically unknown and defer from a person to another. The proposed approach uses only the exoskeleton nominal model while the system upper bounds are adjusted adaptively. No prior knowledge of the exact dynamic model and upper bounds of uncertainties is required. Finite time stability and convergence are proven using Lyapunov theory. Experiments were performed with healthy subjects to evaluate the performance and the efficiency of the proposed controller in tracking trajectories that correspond to passive arm movements.

 

via Adaptive integral terminal sliding mode control for upper-limb rehabilitation exoskeleton – ScienceDirect

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[WEB SITE] Project3 – Flexo-glove

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Project Description

Flexo-glove is a 3D printed soft exoskeleton robotic glove with compact and streamlined design for assistance in activities of daily livings and rehabilitation purposes of patients with hand function impairment.

Specifications:

  • Overall weight of 330g including battery
  • Providing 22N pinch force, 48N power grasp force and object grasp size of up to 81mm in diameter
  • Two control modes: intention-sensing via wireless surface EMG for assistive mode and externally-directed via an accompanying smartphone

Project Details: —> Visit site

My Role:

  • Initiated the project with the idea of using soft 3D printed materials in design of the Flexo-glove inspired by X-Limb
  • Performed feasibility study for using cable-driven mechanism in actuation of rehabilitation glove
  • Leading a group of four mechatronics engineering students to fabricate the prototype and characterise the grip forces

Awards

  • Received Dyason fellowship, $5000 travel fellowship awarded by Melbourne Robotic Lab. to visit Harvard BioRobotics Lab

Related Publications

 A. Mohammadi, J. Lavranos, R. D. Howe, P. Choong and D. Oetomo

  Flexo-glove: A 3D Printed Soft Exoskeleton Robotic Glove for Impaired Hand Rehabilitation and Assistance

  40th International Engineering in Medicine and Biology Conference (EMBC), 2018.

Full Text  PDF 

via Project3 – Flexo-glove

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[WEB SITE] How the National Stroke Association is Advancing Stroke Rehabilitation with Exoskeleton Technology

The National Stroke Association’s mission is to reduce the incidence and The National Stroke Association’s mission is to reduce the incidence and impact of stroke through education and programs focused on prevention, treatment, rehabilitation and support that addresses the needs of stroke survivors, caregivers and healthcare professionals in the stroke community nationwide. The National Stroke Association provides services to more than 90,000 stroke survivors, 30,000 caregivers and 110,000 healthcare professionals in the U.S. and Canada, with the number of individuals benefiting from the National Stroke Association’s services and resources growing every day.

The National Stroke Association and Ekso Bionics have formed an educational partnership dedicated to increasing awareness of and access to advanced stroke rehabilitation exoskeleton technology that enables earlier mobility and restored independence for survivors of stroke.

The partnership between the National Stroke Administration and Ekso Bionics [is] very beneficial, and it’s very appropriate that they use the term “Hope After Stroke” because it’s true. There is hope after the stroke.”

—JESSICA “JESS” MCNAIR, STROKE SURVIVOR

Moving As One for Hope After Stroke

Jessica McNair, Stroke Survivor

An estimated 17 million people around the world experience a strokeeach year. More than 60% of survivors of acute stroke find themselves unable to walk or in need of intervention in walking. Impaired ambulation is greatly associated with fall risks, dependency, limited participation in social activities, and lower quality of life.

However, with the advent of robotic technologies, such as the EksoGT™, the first FDA-cleared exoskeleton device for stroke rehabilitation, the possibility of assisting with ambulation may aid the recovery process by providing earlier mobility and restored independence.

The National Stroke Association and Ekso Bionics educational campaign will include three branches:

National and Regional Push to Elevate Survivor Voices

Showcasing survivors of stroke and their care team in national and regional arenas to highlight the impact of robotic exoskeleton technologies in rehabilitation.

 

Visit Site —> National Stroke Association Partnership | Ekso Bionics

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[REVIEW] Development of Upper Limb Assistive Robotic Devices for Arm Functionality Rehabilitation- Full Text PDF

ABSTRACT

Use of assistive robotic devices and exoskeletons help to achieve the main purpose of
rehabilitation and increased functionality in medical sector. In order to treat patients after stroke or with a condition of myasthenia, physiotherapy is needed for rehabilitating the weakened set of muscles. The exoskeleton devices not only treat the patient well but also help them to relearn the basic movements of the affected limb. They help strengthen the weak part/limb of a person withcondition of partial paralysis / myasthenia with the help of assistive exoskeleton rehabilitation device via training sessions to improve daily primary activities.

I. Introduction

In our country, every year there are almost a million people affected with paralysis and
myasthenia. According to social security disability (S.S.D.) myasthenia is a disability and there is no cure. But it can be treated with medication, physiotherapy and sometimes surgery. To avoid the surgery stage, in this condition the affected patient needs to take specific treatment to give considerable strength to the affected limb. Myasthenia is the state in which abnormal weakening of muscles takes place. It is caused due to severe strokes & accidental nerve damage. In most of the cases severe strokes & nerve damage leads to weakening of arm muscles & it becomes necessary to get expensive physiotherapies in rehabilitation centers or hospitals. Here a particular device that is perfectly designed to impart confidence in the patient to exercise by themselves and
work efficiently to strengthen the muscles of affected limb is beneficial, under the guidance of a physiotherapist. In this paper, we will discuss different devices/exoskeleton which are used for rehabilitation of weak muscles to find the most effective device and ways by which they achieve their objective of strengthening the weakened part or a limb and regain its functionality.

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[ARTICLE] Pilot testing of the spring operated wearable enhancer for arm rehabilitation (SpringWear) – Full Text

Abstract

Background

Robotic devices for neurorehabilitation of movement impairments in persons with stroke have been studied extensively. However, the vast majority of these devices only allow practice of stereotyped components of simulated functional tasks in the clinic. Previously we developed SpringWear, a wearable, spring operated, upper extremity exoskeleton capable of assisting movements during real-life functional activities, potentially in the home. SpringWear assists shoulder flexion, elbow extension and forearm supination/pronation. The assistance profiles were designed to approximate the torque required to move the joint passively through its range. These three assisted DOF are combined with two passive shoulder DOF, allowing complex multi-joint movement patterns.

Methods

We performed a cross-sectional study to assess changes in movement patterns when assisted by SpringWear. Thirteen persons with chronic stroke performed range of motion (ROM) and functional tasks, including pick and place tasks with various objects. Sensors on the device measured rotation at all 5 DOF and a kinematic model calculated position of the wrist relative to the shoulder. Within subject t-tests were used to determine changes with assistance from SpringWear.

Results

Maximum shoulder flexion, elbow extension and forearm pronation/supination angles increased significantly during both ROM and functional tasks (p < 0.002). Elbow flexion/extension ROM also increased significantly (p < 0.001). When the subjects volitionally held up the arm against gravity, extension at the index finger proximal interphalangeal joint increased significantly (p = 0.033) when assisted by SpringWear. The forward reach workspace increased 19% (p = 0.002). Nine subjects could not complete the functional tasks unassisted and only one showed improvement on task completion with SpringWear.

Conclusions

SpringWear increased the usable workspace during reaching movements, but there was no consistent improvement in the ability to complete functional tasks. Assistance levels at the shoulder were increased only until the shoulder could be voluntarily held at 90 degrees of flexion. A higher level of assistance may have yielded better results. Also combining SpringWear with HandSOME, an exoskeleton for assisting hand opening, may yield the most dramatic improvements in functional task performance. These low-cost devices can potentially reduce effort and improve performance during task practice, increasing adherence to home training programs for rehabilitation.

Background

There are 800,000 new strokes in the United States each year [1]. Many survivors experience debilitating motor impairments in the upper extremity that negatively affect functional capacity and quality of life. Impairments can include weakness [2] and lack of coordination between different muscle groups [3]. Fifty percent of stroke survivors older than 64 have persistent hemiparesis at six months post-stroke and 26% are dependent in activities of daily living (ADL) [1]. Unfortunately, a very high level of upper extremity motor control may be needed before the impaired limb is actually incorporated into ADL. Stroke patients often appear to have adequate movement ability when observed in the laboratory, but don’t use the limb with the expected regularity [4].

Neurorehabilitation of these impairments is possible with task-specific repetitive movement practice that incorporates high repetition, volitional effort, and successful completion of tasks to prevent frustration and maintain motivation [5]. Robotics has been studied extensively as a means of assisting movements with forces applied to the limb, allowing completion of movements that would otherwise be impossible to complete unassisted. A recent meta-analysis of 34 studies including 1160 subjects found that robotic devices produced larger gains in arm function, strength and ADL ability than comparison interventions [6]. However, authors concluded the advantages of robotic therapy may not be clinically relevant. The vast majority of these studies involved patients traveling to the clinic on a regimented schedule to practice components of tasks. Home-based approaches may be more effective in increasing the amount of limb use, in particular devices that can assist movements while subjects perform real-world ADL.

Many robotic treatments involve providing partial support of the arm against gravity to enable practice of reaching within a larger workspace [78]. This approach is motivated by research that has shown that many stroke patients have an abnormal synergy whereby elevation of the shoulder against gravity impairs the ability to extend the elbow [91011]. More recently, work has shown an abnormal coupling of proximal and distal arm muscles, such that activation level of proximal muscles and level of arm support can affect control of hand and wrist muscles [1213]. However current robotic approaches that provide gravity compensation do not allow practice of tasks in real-world environments, such as in the home, while standing or when performing bimanual tasks. Also, the provision of gravity support may not completely overcome distal weakness in elbow extension and forearm supination [14]. Additionally, many robotic paradigms rely on repetitive performance of components of functional tasks, for example, planar reaching movements. This contradicts motor learning studies that suggest retention and generalization of skills requires task variability [151617].

In previous work we developed a wearable passively actuated hand exoskeleton (HandSOME) that increases finger ROM and function [1819]. However, some subjects were found to be inappropriate for HandSOME because of proximal weakness, and while the HandSOME enabled adequate range of motion at the fingers, some subjects had difficulty supinating the forearm enough to properly grasp certain objects. Furthermore, finger extension ability would degrade as the arm was lifted against gravity. This motivated the development of a wearable arm exoskeleton called the spring-operated wearable enhancer (SpringWear). Springs apply an angle-dependent torque to the joints, with the goal of increasing ROM, repertoire of possible movements, task variability and success in completing tasks.

Overall, the goal was to enable effective use of the impaired limb in the home environment, thereby allowing patients a highly variable, but meaningful task practice. SpringWear can also reduce effort in task completion promoting greater adherence to home practice schedules. At the shoulder, SpringWear provides partial gravity compensation, which reduces the muscle forces at the shoulder needed to lift the arm. With proper selection of assistance level, the initiation and control of movements are still under patient control but less effort is needed and a larger ROM can be achieved. At the elbow, patients often can flex the joint, but have limited extension, so extension torques are applied to increase elbow extension range. A similar strategy is used to assist forearm supination/pronation. In order to benefit from SpringWear, patients should have some active movement at the joints, but for profoundly weak patients, this approach will not be effective. In these patients, powered exoskeletons may be needed, since they can move the limb throughout a larger workspace than spring powered devices. However, powered devices are much more expensive and complicated to integrate into a wearable device and compact designs are often high impedance, requiring sensors to infer the patient’s intended movement trajectory, which may be difficult in very low level patients.

In this study, chronic stroke patients performed a number of tasks with and without assistance from the SpringWear, and the kinematics of the movements were compared. If successful, SpringWear combined with HandSOME, may provide an inexpensive home-based intervention for a wide range of severe to moderately impaired stroke patients.

Methods

SpringWear design

An upper limb exoskeleton, in general, needs to be adaptable to different segment lengths and have a high number of DOFs in order to allow realistic movement practice with many anatomical joint axes involved [20]. With five DOFs, SpringWear was designed to provide assistance to forearm supination/pronation, elbow extension, shoulder flexion, while providing passive joints for shoulder horizontal abduction/adduction and internal/external rotation to allow realistic upper limb movements (Fig. 1). The design uses rubber bands or bungee cords as springs to provide the assistance. These profiles can be customized for each subject by adjusting the stiffness of the springs, which is dependent on impairment level.

 

Fig. 1 Full Assembly of SpringWear with back splint. Double-headed arrows represents five degrees of freedom. Assistance was applied at shoulder FE, elbow FE, and supination/pronation

[…]

Continue —> Pilot testing of the spring operated wearable enhancer for arm rehabilitation (SpringWear) | Journal of NeuroEngineering and Rehabilitation | Full Text

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[ARTICLE] Design and Preliminary Feasibility Study of a Soft Robotic Glove for Hand Function Assistance in Stroke Survivors – Full Text

Various robotic exoskeletons have been proposed for hand function assistance during activities of daily living (ADL) of stroke survivors. However, traditional exoskeletons involve the use of complex rigid systems that impede the natural movement of joints, and thus reduce the wearability and cause discomfort to the user. The objective of this paper is to design and evaluate a soft robotic glove that is able to provide hand function assistance using fabric-reinforced soft pneumatic actuators. These actuators are made of silicone rubber which has an elastic modulus similar to human tissues. Thus, they are intrinsically soft and compliant. Upon air pressurization, they are able to support finger range of motion (ROM) and generate the desired actuation of the finger joints. In this work, the soft actuators were characterized in terms of their blocked tip force, normal and frictional grip force outputs. Combining the soft actuators and flexible textile materials, a soft robotic glove was developed for grasping assistance during ADL for stroke survivors. The glove was evaluated on five healthy participants for its assisted ROM and grip strength. Pilot test was performed in two stroke survivors to evaluate the efficacy of the glove in assisting functional grasping activities. Our results demonstrated that the actuators designed in this study could generate desired force output at a low air pressure. The glove had a high kinematic transparency and did not affect the active ROM of the finger joints when it was being worn by the participants. With the assistance of the glove, the participants were able to perform grasping actions with sufficient assisted ROM and grip strength, without any voluntary effort. Additionally, pilot test on stroke survivors demonstrated that the patient’s grasping performance improved with the presence and assistance of the glove. Patient feedback questionnaires also showed high level of patient satisfaction and comfort. In conclusion, this paper has demonstrated the possibility of using soft wearable exoskeletons that are more wearable, lightweight, and suitable to be used on a daily basis for hand function assistance of stroke survivors during activities of daily living.

Introduction

The ability to perform basic activities of daily living (ADL) impacts a person’s quality of life and independence (Katz, 1983Andersen et al., 2004). However, an individual’s independence to perform ADLs is jeopardized due to hand motor impairments, which can be observed in patients with neurological disorders such as stroke. In order to improve hand motor functions in terms of strength and range of motion (ROM) (Kutner et al., 2010), stroke survivors undergo rehabilitation programs comprising repetitive practice of simulated ADL tasks (Michaelsen et al., 2006). Normally, patients undergo rehabilitation exercises in a specialized rehabilitation center under the guidance of physiotherapists or occupational therapists. However, due to increasing patient population, it is foreseen that there will be a shortage of physiotherapists to assist in the rehabilitative process. Thus, there will be comparatively less therapy time, which will eventually lead to a slower recovery process for the patients. Over the past decade, technological developments in robotics have facilitated the rehabilitative process and have shown potential to assist patients in their daily life (Maciejasz et al., 2014). One example of such a device is the hand exoskeleton, which is secured around the hand to guide and assist the movement of the encompassed joints. However, due to the complexity of the hand, designing a hand exoskeleton remains a challenging task.

Traditional hand exoskeletons involve the use of rigid linkage-based mechanisms. In this kind of mechanism, rigid components, such as linear actuators, rotary motors, racks, and pinions as well as rigid linkages are normally involved (Worsnopp et al., 2007Rotella et al., 2009Martinez et al., 2010). To assist hand movements that have high degrees of freedom (DOFs), traditional exoskeletons can be incorporated with a substantial number of actuators to achieve the requirement. However, this means that their application is limited due to the increasing bulkiness for higher DOFs. Therefore, these devices are normally restricted in clinical settings and not suitable for performing home therapy. Additionally, their rigidity, weight and constraint on the non-actuated DOFs of the joints pose complications. As a result, the level of comfort and safety of patients is reduced. In view of this, there is an apparent need for the development of exoskeletons that may be used in both clinical and home settings. A lightweight and wearable exoskeleton may allow patients to bring back home to continue daily therapy or to serve as an assistive device for the ADLs.

The development of wearable robotic exoskeletons serves to provide an alternative approach toward addressing this need. Instead of using rigid linkage as an interface between the hand and the actuators, wearable exoskeletons typically utilize flexible materials such as fabric (Sasaki et al., 2004Yap et al., 2016a) and polymer (Kang et al., 2016), driven by compliant actuators such as cables (Sangwook et al., 2014Xiloyannis et al., 2016) and soft inflatable actuators (Polygerinos et al., 2015dYap et al., 2016c). Therefore, they are more compliant and lightweight compared to the rigid linkage-based mechanism. Cable-driven based exoskeletons involve the use of cables that are connected to actuators in the form of electrical motors situated away from the hand (Nilsson et al., 2012Ying and Agrawal, 2012Sangwook et al., 2014Varalta et al., 2014). By providing actuations on both dorsal and palmar sides of the hand, bi-directional cable-driven movements are possible (Kang et al., 2016). These cables mimic the capability of the tendons of the human hand and they are able to transmit the required pulling force to induce finger flexion and extension. However, the friction of the cable, derailment of the tendon, and inaccurate routing of the cable due to different hand dimensions can affect the efficiency of force transmission in the system.

On the other hand, examples of the soft inflatable actuators are McKibben type muscles (Feifei et al., 2006Tadano et al., 2010), sheet-like rubber muscles (Sasaki et al., 2004Kadowaki et al., 2011), and soft elastomeric actuators (Polygerinos et al., 2015b,cYap et al., 2015); amongst which, soft elastomeric actuators have drawn increasing research interest due to their high compliance (Martinez et al., 2013). This approach typically embeds pneumatic chamber networks in elastomeric constructs to achieve different desired motions with pressurized air or water (Martinez et al., 2012). Soft elastomeric actuators are highly customizable. They are able to achieve multiple DOFs and complex motions with a single input, such as fluid pressurization. The design of a wearable hand exoskeleton that utilizes soft elastomeric actuators is usually simple and does not require precise routing for actuation, compared to the cable-driven mechanism. Thus, the design reduces the possibility of misalignment and the setup time. These properties allow the development of hand exoskeletons that are more compliant and wearable, with the ability to provide safe human-robot interaction. Additionally, several studies have demonstrated that compactness and ease of use of an assistive device critically affect its user acceptance (Scherer et al., 20052007). Thus, these exoskeletons provide a greater chance of user acceptance.

Table 1 summarizes the-state-of-art of soft robotic assistive glove driven by inflatable actuators. Several pioneer studies on inflatable assistive glove have been conducted by Sasaki et al. (2004)Kadowaki et al. (2011) and Polygerinos et al. (2015a,b,c). Sasaki et al. have developed a pneumatically actuated power assist glove that utilizes sheet-like curved rubber muscle for hand grasping applications. Polygerinos et al. have designed a hydraulically actuated grip glove that utilizes fiber-reinforced elastomeric actuators that can be mechanically programmed to generate complex motion paths similar to the kinematics of the human finger and thumb. Fiber reinforcement has been proved to be an effective method to constrain the undesired radial expansion of the actuators that does not contribute to effective motion during pressurization. However, this method limits the bending capability of the actuators (Figure S1); as a result, higher pressure is needed to achieve desired bending.

Table 1. Hand assistive exoskeletons driven by inflatable actuators.

This paper presents the design and preliminary feasibility study of a soft robotic glove that utilizes fabric-reinforced soft pneumatic actuators. The intended use of the device is to support the functional tasks during ADLs, such as grasping, for stroke survivors. The objectives of this study were to characterize the soft actuators in terms of their force output and to evaluate the performance of the glove with healthy participants and stroke survivors. The glove was evaluated on five healthy participants in order to determine the ROM of individual finger joints and grip strength achieved with the assistance of the glove. Pilot testing with two stroke survivors was conducted to evaluate the feasibility of the glove in providing grasping assistance for ADL tasks. We hypothesized that with the assistance of the glove, the grasping performance of stroke patients improved.

Specific contributions of this work are listed as follows:

(a) Presented fabric-reinforcement as an alternative method to reinforce soft actuators, which enhanced the bending capability and reduced the required operating pressure of the actuators,

(b) Utilized the inherence compliance of soft actuators and allowed the actuators to achieve multiple motions to support ROM of the human fingers,

(c) Integrated elastic fabric with soft actuators to enhance the extension force for finger extension,

(d) Designed and characterized a soft robotic glove using fabric-reinforced soft actuators with the combination of textile materials, and

(e) Conducted pilot tests with stroke survivors to evaluate the feasibility of the glove in providing functional assistance for ADL tasks.

Design Requirements and Rationale

The design requirements of the glove presented in this paper are similar to those presented by Polygerinos et al. (2015a,b,c) in terms of design considerations, force requirements, and control requirements. For design considerations, weight is the most important design criterion when designing a hand exoskeleton. Previous studies have identified the threshold for acceptable weight of device on the hand, which is in the range of 400–500 g (Aubin et al., 2013Gasser and Goldfarb, 2015). Cable-driven, hydraulic, and pneumatic driven mechanisms are found to be suitable options to meet the criteria. To develop a fully portable system for practical use in home setting, reduction in the weight of the glove as well as the control system is required. The total weight of the control system should not exceed 3 kg (Polygerinos et al., 2015a,b,c). In this work, the criteria for the weight of the glove and control system are defined as: (a) the weight of the glove should be <200 g, and (b) the weight of the control system should be <1.5 kg.

Considering the weight requirement, hydraulic systems are not ideal for this application, as the requirement of a water reservoir for hydraulic control systems and actuation of the actuators with pressurized water will add extra weight to the hand. The second consideration is that the hand exoskeleton should allow fast setup time. Therefore, it is preferable for the hand exoskeleton to fit the hand anatomy rapidly without precise joint alignment. Compared to cable-driven mechanisms, soft pneumatic actuators are found to be more suitable as they allow rapid customization to different finger length. Additionally, they do not require precise joint alignment and cable routing for actuation as the attachment of the soft pneumatic actuators on the glove is usually simple. Therefore, in this work, pneumatic mechanisms were selected. Using pneumatic mechanism, Connelly et al. and Thielbar et al. have developed a pneumatically actuated glove, PneuGlove that is able to provide active extension assistance to each finger while allowing the wearer to flex the finger voluntarily (Connelly et al., 2010Thielbar et al., 2014). The device consists of five air bladders on the palmar side of the glove. Inflation of the air bladders due to air pressurization created an extension force that extends the fingers. However, due to the placement of the air bladders on the palmar side, grasping activities such as palmar and pincer grasps were more difficult. Additionally, this device is limited to stroke survivors who are able to flex their fingers voluntarily.

In this work, the soft robotic glove is designed to provide functional grasping assistance for stroke survivors with muscle weakness and impairments in grasping by promoting finger flexion. While the stroke survivors still preserve the ability to modulate grip force within their limited force range, the grip release (i.e., hand opening) is normally prolonged (Lindberg et al., 2012). Therefore, the glove should assist with grip release by allowing passive finger extension via reinforced elastic components, similar to Saeboflex (Farrell et al., 2007) and HandSOME (Brokaw et al., 2011). The elastic components of these devices pull the fingers to the open hand state due to increased tension during finger flexion. Additionally, the glove should generate the grasping force required to manipulate and counteract the weight of the objects of daily living, which are typically below 1.07 kg (Smaby et al., 2004). Additionally, the actuators in the glove should be controlled individually in order to achieve different grasping configurations required in simulated ADL tasks, such as palmar grasp, pincer grasp, and tripod pinch. For the speed of actuation, the glove should reach full grasping motion in <4 s during simulated ADL tasks and rehabilitation training.

For the actuators, we have recently developed a new type of soft fabric-reinforced pneumatic actuator with a corrugated top fabric layer (Yap et al., 2016a) that could minimize the excessive budging and provide better bending capability compared to fiber-reinforced soft actuators developed in previous studies (Polygerinos et al., 2015c,d). This corrugated top fabric layer allows a small initial radial expansion to initiate bending and then constrains further undesired radial expansion (Figure 1). The detailed comparison of the fiber-reinforced actuators and fabric-reinforced actuators can be found in the Supplementary Material.

 

 

Figure 1. (A) A fabric-reinforced soft actuators with a corrugated fabric layer and an elastic fabric later [Actuator thickness, T= 12 mm, and length, L = 160 mm (Thumb), 170 mm (Little Finger), 180 mm (Index & Ring Fingers), 185 mm (Middle Finger)]. (B) Upon air pressurization, the corrugated fabric layer unfolds and expands due to the inflation of the embedded pneumatic chamber. Radial budging is constrained when the corrugated fabric layer unfolds fully. The elastic fabric elongates during air pressurization and stores elastic energy. The actuator achieves bending and extending motions at the same time. (C) A bending motion is preferred at the finger joints (II, IV, VI). An extending motion is preferred over the bending motion at the finger segments (I, III, V) and the opisthenar (VII).

Continue —>  Frontiers | Design and Preliminary Feasibility Study of a Soft Robotic Glove for Hand Function Assistance in Stroke Survivors | Neuroscience

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[WEB SITE] Robot-Assisted Therapy: What Is Right for Your Clinic?

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One of the advantages of this gait training system is that it uses end-effector technology to assist patients in stepping, while a therapist provides manual facilitation. (Photo by Kevin Hentz)

by Rebecca Martin, OTR/L, OTD, and Dennis Tom-Wigfield, PT, DPT

Investment in therapeutic technologies spans a continuum from elastic bands that cost a few dollars to room-sized mobility and balance systems that require construction build-outs and additional staff. Inhabiting the middle to upper range of this continuum are robotic devices and associated technology, which have become increasingly popular. Though these advanced technologies deserve a thorough cost-benefit analysis and review of competing products prior to purchase, the payoff they may provide in outcomes and efficiency can make the investment well worth the effort.

Among the facility-based technologies that have grabbed recent headlines, robot-assisted therapy is one that may be attractive to healthcare organizations. Robot-assisted therapy is an efficacious method to remediate disability associated with a wide variety of neurological disorders, most notably stroke and spinal cord injury (SCI). Intensity and repetition has been repeatedly demonstrated to be necessary for central nervous system excitation and associated motor learning.1Massed practice, or high-volume repetition, has been shown to improve muscle strength and voluntary function.2 Robot-assisted therapy has the capacity to provide high numbers of specific movements with support or guidance as necessary, ensuring optimal conditions for motor learning and recovery of function.3 Changes can be observed in as little as 6 weeks and peak around 12 weeks of training.4

Nearly all robotic devices include some sort of computer interface, even a virtual reality component, providing the patient and therapist with real-time feedback to improve performance. Robotic devices also allow for quantitative monitoring; measuring changes in strength, range of motion, and trajectory; and illuminating patient engagement trends, time, and effort.3 As the body of literature expands and supports its use, patients are seeking clinics with these resources. Robotic technology has the potential to align patients’ interests in validated strategies with clinics’ interests in efficiency and payor-supported interventions. Clinics have an opportunity to improve patient outcomes and efficiency with which they reach those outcomes by investing in robotic devices. This investment is not trivial, however, and better understanding of the capacity and scope of different devices will help to make sure that everyone’s resources are utilized appropriately.

Assessment: Get the Complete Picture

Before it begins to investigate and trial devices, a clinic should do a careful self-assessment. Clinics should have a good understanding of their patient factors and needs: demographics, diagnoses, and payor mix. Equally important, clinics should have a good understanding of how much of their own resources—money, time, and space—they have to spend. Although money is often considered to be the limiting factor in the acquisition of technology, time and space deserve equal consideration. Nothing would be worse than investing in the perfect body weight support (BWS) gait trainer, only to find that your ceiling is too low to accommodate it. Similarly, clinics should anticipate that therapists will need time outside patient care to learn the devices and that efficiency will suffer in the early learning phase. Clinics will want to consider existing technology and therapist-driven interventions when deciding on their specific needs. Clinics would benefit from having a clear plan for acquisition and incorporation of robotic technology into existing practices. Acquiring too much technology too quickly is a sure way to reduce integration of devices and waste valuable resources.

 

Visit Site —> Robot-Assisted Therapy: What Is Right for Your Clinic? – Rehab Managment

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[ARTICLE] Wearable robotic exoskeleton for overground gait training in sub-acute and chronic hemiparetic stroke patients: preliminary results – Full Text PDF

BACKGROUND: Recovery of therapeutic or functional ambulatory capacity in post-stroke patients is a primary goal of rehabilitation. Wearable powered exoskeletons allow patients with gait dysfunctions to perform over-ground gait training, even immediately after the acute event.
AIM: To investigate the feasibility and the clinical effects of an over-ground walking training with a wearable powered exoskeleton in sub-acute and chronic stroke patients.
DESIGN: Prospective, pilot pre-post, open label, non-randomized experimental study.
SETTING: A single neurological rehabilitation center for inpatients and outpatients.
POPULATION: Twenty-three post-stroke patients were enrolled: 12 sub-acute (mean age: 43.8±13.3 years, 5 male and 7 female, 7 right hemiparesis and 5 left hemiparesis) and 11 chronic (mean age: 55.5±15.9 years, 7 male and 4 female, 4 right hemiparesis and 7 left hemiparesis) patients.
METHODS: Patients underwent 12 sessions (60 min/session, 3 times/week) of walking rehabilitation training using Ekso™, a wearable bionic suit that enables individuals with lower extremity disabilities and minimal forearm strength to stand up, sit down and walk over a flat hard surface with a full weight-bearing reciprocal gait. Clinical evaluations were performed at the beginning of the training period (t0), after 6 sessions (t1) and after 12 sessions (t2) and were based on the Ashworth scale, Motricity Index, Trunk Control Test, Functional Ambulation Scale, 10-Meter Walking Test, 6-Minute Walking Test, and Walking Handicap Scale. Wilcoxon’s test (P<0.05) was used to detect significant changes.
RESULTS: Statistically significant improvements were observed at the three assessment periods for both groups in Motricity Index, Functional Ambulation Scale, 10-meter walking test, and 6-minute walking test. Sub-acute patients achieved statistically significant improvement in Trunk Control Test and Walking Handicap Scale at t0-t2. Sub-acute and chronic patient did not achieve significant improvement in Ashworth scale at t0-t2.
CONCLUSIONS: Twelve sessions of over-ground gait training using a powered wearable robotic exoskeleton improved ambulatory functions in sub-acute and chronic post-stroke patients. Large, randomized multicenter studies are needed to confirm these preliminary data.
CLINICAL REHABILITATION IMPACT: To plan a completely new individual tailored robotic rehabilitation strategy after stroke, including task-oriented over-ground gait training.

Full Text PDF

via Wearable robotic exoskeleton for overground gait training in sub-acute and chronic hemiparetic stroke patients: preliminary results – European Journal of Physical and Rehabilitation Medicine 2017 October;53(5):676-84 – Minerva Medica – Journals

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[Abstract] What does best evidence tell us about robotic gait rehabilitation in stroke patients: A systematic review and meta-analysis

Highlights

  • Recovery of walking function is one of the main goals of patients after stroke.
  • RAGT may be considered a valuable tool in improving gait abnormalities.
  • The earlier the gait training starts, the better the motor recovery.

Abstract

Background

Studies about electromechanical-assisted devices proved the validity and effectiveness of these tools in gait rehabilitation, especially if used in association with conventional physiotherapy in stroke patients.

Objective

The aim of this study was to compare the effects of different robotic devices in improving post-stroke gait abnormalities.

Methods

A computerized literature research of articles was conducted in the databases MEDLINE, PEDro, COCHRANE, besides a search for the same items in the Library System of the University of Parma (Italy). We selected 13 randomized controlled trials, and the results were divided into sub-acute stroke patients and chronic stroke patients. We selected studies including at least one of the following test: 10-Meter Walking Test, 6-Minute Walk Test, Timed-Up-and-Go, 5-Meter Walk Test, and Functional Ambulation Categories.

Results

Stroke patients who received physiotherapy treatment in combination with robotic devices, such as Lokomat or Gait Trainer, were more likely to reach better results, compared to patients who receive conventional gait training alone. Moreover, electromechanical-assisted gait training in association with Functional Electrical Stimulations produced more benefits than the only robotic treatment (−0.80 [−1.14; −0.46], p > .05).

Conclusions

The evaluation of the results confirm that the use of robotics can positively affect the outcome of a gait rehabilitation in patients with stroke. The effects of different devices seems to be similar on the most commonly outcome evaluated by this review.

 

via What does best evidence tell us about robotic gait rehabilitation in stroke patients: A systematic review and meta-analysis – Journal of Clinical Neuroscience

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