Exo-Glove Poly III: Grasp Assistance by Modulating Thumb and Finger Motion Sequence with a Single Actuator

In daily living, people grasp an object through the steps of "pre-shaping" and "enclosing," with the thumb playing a crucial role with its multiple degrees of freedom. When assisting individuals with hand impairments using soft wearable robots, it is important to simplify the robot by reducing the number of actuators and to provide different grasping strategies based on various objects being handled. In this article, we propose a tendon-driven soft wearable hand robot, Exo-Glove Poly III, that uses a single actuator for assisting two types of grasping strategies for people with hand impairment. To move the thumb and other fingers with a single actuator, we developed a slack-based sequential mechanism that allows movements to occur at different timings by varying the initial slack lengths of each tendon. Based on our observations of grasping strategies and the proposed novel actuation system, a slack-based sequential actuator (318 g, including electronic circuits) was designed and integrated with the glove (90 g) using a commercial armband to make the system portable. The robotic system was evaluated by a healthy subject, showing how the thumb moves by the tendon routings and how the mechanism works for each grasping strategy.

Exo-Glove Shell: A Hybrid Rigid-Soft Wearable Robot for Thumb Opposition with an Under-Actuated Tendon-Driven System

Usability and functionality are important when designing hand-wearable robots; however, satisfying both indicators remains a challenging issue, even though researchers have made important progress with state-of-the-art robot components. Although hand-wearable robots require sufficient actuators and sensors considering their functionality, these components complicate the robot. Further, robot compliance should be carefully considered because it affects both indicators. For example, a robot's softness makes it compact (improving usability) but also induces inaccurate force transmission (impacting functionality). To address this issue, we present in this paper a tendon-driven, hybrid, hand-wearable robot, named Exo-Glove Shell. The proposed robot assists in three primitive motions (i.e., thumb opposition motion, which is known as one of the most important hand functions, and flexion/extension of the index/middle fingers) while employing only four actuators by using an under-actuation mechanism. The Exo-Glove Shell was designed by combining a soft robotic body with rigid tendon router modules. The use of soft garments enables the robot to be fitted well to users without customization or adjustment of the mechanisms; the metal routers facilitate accurate force transmission. User tests conducted with an individual with a spinal cord injury (SCI) found that the robot could sufficiently and reliably assist in three primitive motions through its four actuators. The research also determined that the robot can assist in various postures with sufficient stability. Based on the grasp stability index proposed in this paper, user stability-when assisted by the proposed robot-was found to be 4.75 times that of an SCI person who did not use the Exo-Glove Shell.

Grasp Force Assistance via Throttle-based Wrist Angle Control on a Robotic Hand Orthosis for C6-C7 Spinal Cord Injury

Individuals with hand paralysis resulting from C6-C7 spinal cord injuries frequently rely on tenodesis for grasping. However, tenodesis generates limited grasping force and demands constant exertion to maintain a grasp, leading to fatigue and sometimes pain. We introduce the MyHand-SCI, a wearable robot that provides grasping assistance through motorized exotendons. Our user-driven device enables independent, ipsilateral operation via a novel Throttle-based Wrist Angle control method, which allows users to maintain grasps without continued wrist extension. A pilot case study with a person with C6 spinal cord injury shows an improvement in functional grasping and grasping force, as well as a preserved ability to modulate grasping force while using our device, thus improving their ability to manipulate everyday objects. This research is a step towards developing effective and intuitive wearable assistive devices for individuals with spinal cord injury.

Expanding functional workspace for people with C5-C7 spinal cord injury with supernumerary dorsal grasping

Spinal cord injuries (SCI) substantially affect sensory, motor, and autonomous functions below the level of injury, reducing the independence and quality of life for affected individuals. Specifically, people with SCI between C5 and C7 cervical levels encounter limitations in voluntary finger and wrist flexion, reducing grasp capability. Compensatory strategies like tenodesis grasp, whereby wrist extension passively closes the fingers, remain; this is effective for small and light objects but insufficient for heavier ones. Typically, wearable assistive exoskeletons are designed to actuate a person's fingers, however, such devices are sensitive to anatomical variability, such as hand size and joint contractures. The Dorsal Grasper is a wearable device designed to address this challenge by leveraging voluntary wrist extension and providing human-robot collaborative grasping capabilities with underactuated supernumerary fingers on the back of the hand. In this study, we introduce kinematic assessment methods that we use to show how the Dorsal Grasper expands the graspable workspace and reduces trunk motion, especially in situations where the use of a wheelchair restricts the individual's posture. Our functionally relevant experiments with multiple SCI participants demonstrate the Dorsal Grasper's potential as a versatile assistive solution for enhancing grasping capability in individuals with distinct SCI profiles.

A magnetically controlled soft robotic glove for hand rehabilitation

For individuals with hand motor function losses, rehabilitation is necessary for regaining strength and range of motion to accomplish daily activities. Typically within a clinical setting, repetitive strength-based and task-specific exercises are prescribed. However, these therapies are generally costly and non-portable, limiting patient accessibility and rendering patient compliance impractical. There is thus a clinical need for a system that is low-cost, portable, and accessible to improve patient compliance and outcomes. This work presents a proof-of-concept magnetically-controlled glove to provide targeted resistance-based rehabilitation for patients with hand motor impairments. The glove is inexpensive, customizable, and portable, allowing for use within a clinic and at home. Customizable resistance is achieved by electropermanent magnets (EPMs), which locally control magnetic attraction of the digits and produce rapid stiffness changes from magnetically induced jamming. Various rehabilitative exercises using the glove are demonstrated and the magnetic fields can be customized to provide necessary resistance.

The usefulness of assistive soft robotics in the rehabilitation of patients with hand impairment: A systematic review

INTRODUCTION

Loss of hand function causes severe limitations in activity in daily living. The hand-soft robot is one of the methods that has recently been growing to increase the patient's independence. The purpose of the present systematic review was to provide a classification, a comparison, and a design overview of mechanisms and the efficacy of the soft hand robots to help researchers approach this field.

METHODS

The literature research regarding such tools was conducted in PubMed, Google Scholar, Science Direct, and Cochrane Central Register for Controlled Trials. We included peer-reviewed studies that considered a soft robot glove as an assistive device to provide function. The two investigators screened the titles and abstracts, then independently reviewed the full-text articles. Disagreements about inclusion were resolved by consensus or a third reviewer.

RESULTS

A total of 15 articles were identified, describing 210 participants (23 healthy subjects). The tools were in three categories according to their actuation type (pneumatic system, cable-driven, another design). The most critical outcomes in studies included functional tasks (fourteen studies), grip strength (four studies), range of motion (ROM) (five studies), and user satisfaction (five studies).

DISCUSSION

Function and grip parameters are the most common critical parameters for tests of hand robots. Cable-driven transmission and soft pneumatic actuators are the most common choices for the actuation unit. Radder et al. study had the highest grade from other studies. That was the only RCT among studies.

CONCLUSION

Although few soft robotic gloves can be considered ready to reach the market, it seems these tools have the potential to be practical for people with a disability. But, we lack consistent evidence of comparing two or more soft robot gloves on the hand functions. Future research needs to assess the effect of soft robotic gloves on people with hand disorders with more populations.

Hand assistive device with suction cup (HADS) technology for poststroke patients

A stroke is a neurological disease that primarily causes paralysis. Besides paraplegia, all other types of paralysis affect the upper extremity. Advanced technologies, such as wearable devices and rehabilitation regimens, are also being developed to enhance the functional ability of a stroke person to grasp and release daily living objects. In this research, we developed a rehabilitation functional assist device combining a flexion and extension mechanism with suction cup technology (hybrid technology) to help post-stroke patients improve their hand grip strength in day-to-day grasping activities. Ten poststroke hemiplegia patients were studied to test the functional ability of the impaired hand by wearing and not wearing the device. The outcomes were validated by three standard clinical tests, such as the Toronto Rehabilitation Institute - Hand Functional Test (TRI-HFT), the Chedoke Arm Hand Activity Inventory (CAHAI-9), and the Fugl-Meyer Assessment (FMA) with overall score improvements of 14.5 ± 3.8-25 ± 2.2 (p = 0.005), 5.4 ± 2.8-10 ± 1.6 (p = 0.008), and 9.6 ± 2.6-17 ± 2.4 (p = 0.005) respectively. The p-value for each of the three evaluations was less than 0.05, indicating significantly improved results and the average feedback score of the participants was 3.8 out of 5. The proposed device significantly increased impaired hand functionality in post-stroke patients. The subjects could complete some of the grasping tasks that they could not grasp without the device.Clinical trial registrationThe Clinical Trial Registry of India approved the work CTRI/2022/02/040495 described in this manuscript.

Kinematics, dynamics and control of stiffness-tunable soft robots

Modeling and control methods for stiffness-tunable soft robots (STSRs) have received less attention compared to standard soft robots. A major challenge in controlling STSRs is their infinite degrees of freedom, similar to standard soft robots. In this paper, demonstrate a novel STSR by combing a soft-rigid hybrid spine-mimicking actuator with a stiffness-tunable module. Additionally, we introduce a new kinematic and dynamic modeling methodology for the proposed STSR. Based on the STSR characteristics, we model it as a series of PRP segments, each composed of two prismatic joints(P) and one revolute joint(R). This method is simpler, more generalizable, and more computationally efficient than existing approaches. We also design a multi-input multi-output (MIMO) controller that directly adjusts the pressure of the STSR's three pneumatic chambers to precisely control its posture. Both the novel modeling methodology and MIMO control system are implemented and validated on the proposed STSR prototype.

Exo Supportive Devices: Summary of Technical Aspects

Human societies have been trying to mitigate the suffering of individuals with physical impairments, with a special effort in the last century. In the 1950s, a new concept arose, finding similarities between animal exoskeletons, and with the goal of medically aiding human movement (for rehabilitation applications). There have been several studies on using exosuits with this purpose in mind. So, the current review offers a critical perspective and a detailed analysis of the steps and key decisions involved in the conception of an exoskeleton. Choices such as design aspects, base materials (structure), actuators (force and motion), energy sources (actuation), and control systems will be discussed, pointing out their advantages and disadvantages. Moreover, examples of exosuits (full-body, upper-body, and lower-body devices) will be presented and described, including their use cases and outcomes. The future of exoskeletons as possible assisted movement solutions will be discussed-pointing to the best options for rehabilitation.

Tunable, Textile-Based Joint Impedance Module for Soft Robotic Applications

The design of soft actuators is often focused on achieving target trajectories or delivering specific forces and torques, rather than controlling the impedance of the actuator. This article outlines a new soft, tunable pneumatic impedance module based on an antagonistic actuator setup of textile-based pneumatic actuators intended to deliver bidirectional torques about a joint. Through mechanical programming of the actuators (select tuning of geometric parameters), the baseline torque to angle relationship of the module can be tuned. A high bandwidth fluidic controller that can rapidly modulate the pressure at up to 8 Hz in each antagonistic actuator was also developed to enable tunable impedance modulation. This high bandwidth was achieved through the characterization and modeling of the proportional valves used, derivation of a fluidic model, and derivation of control equations. The resulting impedance module was capable of modulating its stiffness from 0 to 100 Nm/rad, at velocities up to 120°/s and emulating asymmetric and nonlinear stiffness profiles, typical in wearable robotic applications.

MITEx: A Portable Hand Exoskeleton for Assessment and Treatment in Neurological Rehabilitation

This work describes the design and preliminary characterization of a novel portable hand exoskeleton for poststroke rehabilitation. The platform actively mobilizes the index-metacarpophalangeal (I-MCP) joint, and it additionally offers individual rigid support to distal degrees of freedom (DoFs) of the index and thumb. The test-bench characterization proves the capability of the device to render torques at the I-MCP level with high fidelity within frequencies of interest for the application (up to 3 Hz). The introduction of a feed-forward friction compensation at the actuator level lowers the output mechanical stiffness by 32%, contributing to a highly transparent behavior; moreover, the functionality of the platform in rendering different interaction strategies (patient/robot-in-charge) is tested with three healthy subjects, showing the potential of the device to provide assistance as needed.

Bilateral mode exoskeleton for hand rehabilitation with wireless control using 3D printing technology based on IMU sensor

This research aimed to develop an open-source exoskeleton for hand rehabilitation (EHR) device that can be controlled wirelessly in bilateral mode. This design has the advantage of being light and being controlled easily using WiFi-based wireless communication by non-paretic hands. This open-source EHR composed of two parts, namely the master and slave parts, each of which uses a mini ESP32 microcontroller, IMU sensor, and 3D printing. The mean RMSE obtained for all exoskeleton fingers is 9.04°. Since the EHR design is open source, the researchers can create and develop rehabilitation device for the therapeutic process of patients who are paralyzed or partially paralyzed independently using healthy hand.

A Critical Review on Factors Affecting the User Adoption of Wearable and Soft Robotics

In recent years, the advent of soft robotics has changed the landscape of wearable technologies. Soft robots are highly compliant and malleable, thus ensuring safe human-machine interactions. To date, a wide variety of actuation mechanisms have been studied and adopted into a multitude of soft wearables for use in clinical practice, such as assistive devices and rehabilitation modalities. Much research effort has been put into improving their technical performance and establishing the ideal indications for which rigid exoskeletons would play a limited role. However, despite having achieved many feats over the past decade, soft wearable technologies have not been extensively investigated from the perspective of user adoption. Most scholarly reviews of soft wearables have focused on the perspective of service providers such as developers, manufacturers, or clinicians, but few have scrutinized the factors affecting adoption and user experience. Hence, this would pose a good opportunity to gain insight into the current practice of soft robotics from a user's perspective. This review aims to provide a broad overview of the different types of soft wearables and identify the factors that hinder the adoption of soft robotics. In this paper, a systematic literature search using terms such as "soft", "robot", "wearable", and "exoskeleton" was conducted according to PRISMA guidelines to include peer-reviewed publications between 2012 and 2022. The soft robotics were classified according to their actuation mechanisms into motor-driven tendon cables, pneumatics, hydraulics, shape memory alloys, and polyvinyl chloride muscles, and their pros and cons were discussed. The identified factors affecting user adoption include design, availability of materials, durability, modeling and control, artificial intelligence augmentation, standardized evaluation criteria, public perception related to perceived utility, ease of use, and aesthetics. The critical areas for improvement and future research directions to increase adoption of soft wearables have also been highlighted.

Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment

This study proposes a bioinspired exotendon routing configuration for a tendon-based mechanism to provide finger flexion and extension that utilizes a single motor to reduce the complexity of the system. The configuration was primarily inspired by the extrinsic muscle-tendon units of the human musculoskeletal system. The function of the intrinsic muscle-tendon units was partially compensated by adding a minor modification to the configuration of the extrinsic units. The finger kinematics produced by this solution during flexion and extension were experimentally evaluated on an artificial finger and compared to that obtained using the traditional mechanism, where one exotendon was inserted at the distal phalanx. The experiments were conducted on nine healthy subjects who wore a soft exoskeleton glove equipped with the novel tendon mechanism. Contrary to the traditional approach, the proposed mechanism successfully prevented the hyperextension of the distal interphalangeal (DIP) and the metacarpophalangeal (MCP) joints. During flexion, the DIP joint angles produced by the novel mechanism were smaller than the angles generated by the traditional approach for the same proximal interphalangeal (PIP) joint angles. This provided a flexion trajectory closer to the voluntary flexion motion and avoided straining the interphalangeal coupling between the DIP and PIP joints. Finally, the proposed solution generated similar trajectories when applied to a stiff artificial finger (simulating spasticity). The results, therefore, demonstrate that the proposed approach is indeed an effective solution for the envisioned soft hand exoskeleton system.

A low-cost wearable device for portable sequential compression therapy

In 2020, cardiovascular diseases resulted in 25% of unnatural deaths in the United States. Treatment with long-term administration of medication can adversely affect other organs, and surgeries such as coronary artery grafts are risky. Meanwhile, sequential compression therapy (SCT) offers a low-risk alternative, but is currently expensive and unwieldy, and often requires the patient to be immobilized during administration. Here, we present a low-cost wearable device to administer SCT, constructed using a stacked lamination fabrication approach. Expanding on concepts from the field of soft robotics, textile sheets are thermally bonded to form pneumatic actuators, which are controlled by an inconspicuous and tetherless electronic onboard supply of pressurized air. Our open-source, low-profile, and lightweight (140 g) device costs $62, less than one-third the cost the least expensive alternative and one-half the weight of lightest alternative approved by the US Food and Drug Administration (FDA), presenting the opportunity to more effectively provide SCT to socioeconomically disadvantaged individuals. Furthermore, our textile-stacking method, inspired by conventional fabrication methods from the apparel industry, along with the lightweight fabrics used, allows the device to be worn more comfortably than other SCT devices. By reducing physical and financial encumbrances, the device presented in this work may better enable patients to treat cardiovascular diseases and aid in recovery from cardiac surgeries.

Thumb Stabilization and Assistance in a Robotic Hand Orthosis for Post-Stroke Hemiparesis

We propose a dual-cable method of stabilizing the thumb in the context of a hand orthosis designed for individuals with upper extremity hemiparesis after stroke. This cable network adds opposition/reposition capabilities to the thumb, and increases the likelihood of forming a hand pose that can successfully manipulate objects. In addition to a passive-thumb version (where both cables are of fixed length), our approach also allows for a single-actuator active-thumb version (where the extension cable is actuated while the abductor remains passive), which allows a range of motion intended to facilitate creating and maintaining grasps. We performed experiments with five chronic stroke survivors consisting of unimanual resistive-pull tasks and bimanual twisting tasks with simulated real-world objects; these explored the effects of thumb assistance on grasp stability and functional range of motion. Our results show that both active- and passive-thumb versions achieved similar performance in terms of improving grasp force generation over a no-device baseline, but active thumb stabilization enabled users to maintain grasps for longer durations.

Evaluation of Fiber-Reinforced Modular Soft Actuators for Individualized Soft Rehabilitation Gloves

Applying soft actuators to hand motion assist for rehabilitation has been receiving increasing interest in recent years. Pioneering research efforts have shown the feasibility of soft rehabilitation gloves (SRGs). However, one important and practical issue, the effects of users’ individual differences in finger size and joint stiffness on both bending performance (e.g., Range of motion (ROM) and torque) and the mechanical loads applied to finger joints when the actuators are placed on a patient’s hand, has not been well investigated. Moreover, the design considerations of SRGs for individual users, considering individual differences, have not been addressed. These, along with the inherent safety of soft actuators, should be investigated carefully before the practical use of SRGs. This work aimed to clarify the effects of individual differences on the actuator’s performance through a series of experiments using dummy fingers designed with individualized parameters. Two types of fiber-reinforced soft actuators, the modular type for assisting each joint and conventional (whole-finger assist) type, were designed and compared. It was found that the modular soft actuators respond better to individual differences set in the experiment and exhibit a superior performance to the conventional ones. By suitable connectors and air pressure, the modular soft actuators could cope with the individual differences with minimal effort. The effects of the individualized parameters are discussed, and design considerations are extracted and summarized. This study will play an important role in pushing forward the SRGs to real rehabilitation practice.

Intention Detection Strategies for Robotic Upper-Limb Orthoses: A Scoping Review Considering Usability, Daily Life Application, and User Evaluation

Wearable robotic upper limb orthoses (ULO) are promising tools to assist or enhance the upper-limb function of their users. While the functionality of these devices has continuously increased, the robust and reliable detection of the user's intention to control the available degrees of freedom remains a major challenge and a barrier for acceptance. As the information interface between device and user, the intention detection strategy (IDS) has a crucial impact on the usability of the overall device. Yet, this aspect and the impact it has on the device usability is only rarely evaluated with respect to the context of use of ULO. A scoping literature review was conducted to identify non-invasive IDS applied to ULO that have been evaluated with human participants, with a specific focus on evaluation methods and findings related to functionality and usability and their appropriateness for specific contexts of use in daily life. A total of 93 studies were identified, describing 29 different IDS that are summarized and classified according to a four-level classification scheme. The predominant user input signal associated with the described IDS was electromyography (35.6%), followed by manual triggers such as buttons, touchscreens or joysticks (16.7%), as well as isometric force generated by residual movement in upper-limb segments (15.1%). We identify and discuss the strengths and weaknesses of IDS with respect to specific contexts of use and highlight a trade-off between performance and complexity in selecting an optimal IDS. Investigating evaluation practices to study the usability of IDS, the included studies revealed that, primarily, objective and quantitative usability attributes related to effectiveness or efficiency were assessed. Further, it underlined the lack of a systematic way to determine whether the usability of an IDS is sufficiently high to be appropriate for use in daily life applications. This work highlights the importance of a user- and application-specific selection and evaluation of non-invasive IDS for ULO. For technology developers in the field, it further provides recommendations on the selection process of IDS as well as to the design of corresponding evaluation protocols.

Challenges and solutions for application and wider adoption of wearable robots

The science and technology of wearable robots are steadily advancing, and the use of such robots in our everyday life appears to be within reach. Nevertheless, widespread adoption of wearable robots should not be taken for granted, especially since many recent attempts to bring them to real-life applications resulted in mixed outcomes. The aim of this article is to address the current challenges that are limiting the application and wider adoption of wearable robots that are typically worn over the human body. We categorized the challenges into mechanical layout, actuation, sensing, body interface, control, human-robot interfacing and coadaptation, and benchmarking. For each category, we discuss specific challenges and the rationale for why solving them is important, followed by an overview of relevant recent works. We conclude with an opinion that summarizes possible solutions that could contribute to the wider adoption of wearable robots.

Modeling and Evaluation of a Novel Hybrid-Driven Compliant Hand Exoskeleton Based on Human-Machine Coupling Model

This paper presents the modeling design method for a novel hybrid-driven compliant hand exoskeleton based on the human-machine coupling model for the patients who have requirements on training and assisting. Firstly, the human-machine coupling model is established based on the kinematics characteristics of human fingers and the Bernoulli beam formula. On this basis, the variable stiffness flexible hinge (VSFH) is used to drive the finger extension and the cable-driven mechanism is used to implement the movement of the finger flexion. Here, a hand orthosis is designed in the proposed hand exoskeleton to act as the base and maintain the function position of the hand for patients with hand dysfunction. Then, a final design prototype is fabricated to evaluate the proposed modeling method. In the end, a series of experiments based on the prototype is proceeded to evaluate its capabilities on stretching force for extension, bio-imitability, finger flexion capability, and fingertip force. The results show that the prototype has a significant improvement in all aspects of the ability mentioned above, and has good bionics. The proposed design method can be utilized to implement the rapid design of the hybrid-driven compliant hand exoskeleton with the changed requirements. The novel modeling method can be easily applied in personalized design in rehabilitation engineering.

Wearable Robots: An Original Mechatronic Design of a Hand Exoskeleton for Assistive and Rehabilitative Purposes

Robotic devices are being employed in more and more sectors to enhance, streamline, and augment the outcomes of a wide variety of human activities. Wearable robots arise indeed as of-vital-importance tools for telerehabilitation or home assistance targeting people affected by motor disabilities. In particular, the field of “Robotics for Medicine and Healthcare” is attracting growing interest. The development of such devices is a primarily addressed topic since the increasing number of people in need of rehabilitation or assistive therapies (due to population aging) growingly weighs on the healthcare systems of the nation. Besides, the necessity to move to clinics represents an additional logistic burden for patients and their families. Among the various body parts, the hand is specially investigated since it most ensures the independence of an individual, and thus, the restoration of its dexterity is considered a high priority. In this study, the authors present the development of a fully wearable, portable, and tailor-made hand exoskeleton designed for both home assistance and telerehabilitation. Its purpose is either to assist patients during activities of daily living by running a real-time intention detection algorithm or to be used for remotely supervised or unsupervised rehabilitation sessions by performing exercises preset by therapists. Throughout the mechatronic design process, special attention has been paid to the complete wearability and comfort of the system to produce a user-friendly device capable of assisting people in their daily life or enabling recorded home rehabilitation sessions allowing the therapist to monitor the state evolution of the patient. Such a hand exoskeleton system has been designed, manufactured, and preliminarily tested on a subject affected by spinal muscular atrophy, and some results are reported at the end of the article.

A Hand Exoskeleton for Stroke Survivors' Activities of Daily Life. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021;2021:6734-6737. [PMID: 34892653 DOI: 10.1109/embc46164.2021.9629805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Stroke is a leading cause of disability in the U.S. Hand impairment is a common consequence of stroke, potentially impacting all facets of life as the hands are the primary means of interacting with the world. Typically, therapy is the prescribed treatment after stroke. However, a majority of stroke survivors have limited recovery and thus chronic impairment. Assistive, rather than therapeutic, devices may help these individuals restore lost function and improve independence and engagement in society. Current assistive devices, however, typically fail to address the greatest barriers to successful use with stroke survivors. In the hand, weakness and incoordination arise from a seemingly paradoxical combination of limited voluntary activation of muscles and involuntary neuromuscular hyperexcitability. Thus, profound strength deficits can be accompanied by substantial forces opposing the intended movement. The assistive device presented in this paper can provide both sufficient flexion and extension assistance to overcome these barriers. A single actuator for each digit provides flexion or extension assistance through push-pull cables guided along the dorsal side of the hand. User intent can be decoded from Electromyographic (EMG) signals to drive the device throughout the movement. EMG control is customized to the capabilities of each user by examining the voluntary EMG workspace.

Wearable Assistive Robotics: A Perspective on Current Challenges and Future Trends

Wearable assistive robotics is an emerging technology with the potential to assist humans with sensorimotor impairments to perform daily activities. This assistance enables individuals to be physically and socially active, perform activities independently, and recover quality of life. These benefits to society have motivated the study of several robotic approaches, developing systems ranging from rigid to soft robots with single and multimodal sensing, heuristics and machine learning methods, and from manual to autonomous control for assistance of the upper and lower limbs. This type of wearable robotic technology, being in direct contact and interaction with the body, needs to comply with a variety of requirements to make the system and assistance efficient, safe and usable on a daily basis by the individual. This paper presents a brief review of the progress achieved in recent years, the current challenges and trends for the design and deployment of wearable assistive robotics including the clinical and user need, material and sensing technology, machine learning methods for perception and control, adaptability and acceptability, datasets and standards, and translation from lab to the real world.

Soft Exoskeletons: Development, Requirements, and Challenges of the Last Decade

In this article, various investigations on soft exoskeletons are presented and their functional and structural characteristics are analyzed. The present work is oriented to the studies of the last decade and covers the upper and lower joints, specifically the shoulder, elbow, wrist, hand, hip, knee, and ankle. Its functionality, applicability, and main characteristics are exposed, such as degrees of freedom, force, actuators, power transmission methods, control systems, and sensors. The purpose of this work is to show the current trend in the development of soft exoskeletons, in addition to specifying the essential characteristics that must be considered in its design and the challenges that its construction implies.

Single limb cable driven wearable robotic device for upper extremity movement support after traumatic brain injury

Introduction

Recently, soft exosuits have been proposed for upper limb movement assistance, most supporting single joint movements. We describe the design of a portable wearable robotic device (WRD), “Armstrong,” able to support three degrees-of-freedom of arm movements, and report on its feasibility for movement support of individuals with hemiparesis after traumatic brain injury (TBI).

Methods

We introduce Armstrong and report on a pilot evaluation with two male individuals post-TBI (T1 and T2) and two healthy individuals. Testing involved elbow flexion/extension with and without robotic-assisted shoulder stabilization; shoulder abduction with and without robotic-assisted elbow stabilization; and assisted shoulder abduction and flexion. Outcome measures included range of motion and root mean square trajectory and velocity errors.

Results

TBI subjects performed active, passive, hybrid and active assistive movements with Armstrong. Subjects showed improvements in movement trajectory and velocity. T1 benefited from hybrid, active, and assistive modes due to upper extremity weakness and muscle tone. T2 benefited from hybrid and assistive modes due to impaired coordination. Healthy subjects performed isolated movements of shoulder and elbow with minimal trajectory and velocity errors.

Conclusions

This study demonstrates the safety and feasibility of Armstrong for upper extremity movement assistance for individuals with TBI, with therapist supervision.

A soft, synergy-based robotic glove for grasping assistance

This paper presents a soft, tendon-driven, robotic glove designed to augment grasp capability and provide rehabilitation assistance for postspinal cord injury patients. The basis of the design is an underactuation approach utilizing postural synergies of the hand to support a large variety of grasps with a single actuator. The glove is lightweight, easy to don, and generates sufficient hand closing force to assist with activities of daily living. Device efficiency was examined through a characterization of the power transmission elements, and output force production was observed to be linear in both cylindrical and pinch grasp configurations. We further show that, as a result of the synergy-inspired actuation strategy, the glove only slightly alters the distribution of forces across the fingers, compared to a natural, unassisted grasping pattern. Finally, a preliminary case study was conducted using a participant suffering from an incomplete spinal cord injury (C7). It was found that through the use of the glove, the participant was able to achieve a 50% performance improvement (from four to six blocks) in a standard Box and Block test.

An Assistive Soft Wrist Exosuit for Flexion Movements With an Ergonomic Reinforced Glove

Soft exosuits are a promising solution for the assistance and augmentation of human motor abilities in the industrial field, where the use of more symbiotic wearable robots can avoid excessive worker fatigue and improve the quality of the work. One of the challenges in the design of soft exosuits is the choice of the right amount of softness to balance load transfer, ergonomics, and weight. This article presents a cable-driven based soft wrist exosuit for flexion assistance with the use of an ergonomic reinforced glove. The flexible and highly compliant three-dimensional (3D)-printed plastic structure that is sewn on the glove allows an optimal force transfer from the remotely located motor to the wrist articulation and to preserve a high level of comfort for the user during assistance. The device is shown to reduce fatigue and the muscular effort required for holding and lifting loads in healthy subjects for weights up to 3 kg.

Remote Actuation Systems for Fully Wearable Assistive Devices: Requirements, Selection, and Optimization for Out-of-the-Lab Application of a Hand Exoskeleton

Wearable robots assist individuals with sensorimotor impairment in daily life, or support industrial workers in physically demanding tasks. In such scenarios, low mass and compact design are crucial factors for device acceptance. Remote actuation systems (RAS) have emerged as a popular approach in wearable robots to reduce perceived weight and increase usability. Different RAS have been presented in the literature to accommodate for a wide range of applications and related design requirements. The push toward use of wearable robotics in out-of-the-lab applications in clinics, home environments, or industry created a shift in requirements for RAS. In this context, high durability, ergonomics, and simple maintenance gain in importance. However, these are only rarely considered and evaluated in research publications, despite being drivers for device abandonment by end-users. In this paper, we summarize existing approaches of RAS for wearable assistive technology in a literature review and compare advantages and disadvantages, focusing on specific evaluation criteria for out-of-the-lab applications to provide guidelines for the selection of RAS. Based on the gained insights, we present the development, optimization, and evaluation of a cable-based RAS for out-of-the-lab applications in a wearable assistive soft hand exoskeleton. The presented RAS features full wearability, high durability, high efficiency, and appealing design while fulfilling ergonomic criteria such as low mass and high wearing comfort. This work aims to support the transfer of RAS for wearable robotics from controlled lab environments to out-of-the-lab applications.

Myoelectric untethered robotic glove enhances hand function and performance on daily living tasks after stroke

Introduction

Wearable robots controlled using electromyography could motivate greater use of the affected upper extremity after stroke and enable bimanual activities of daily living to be completed independently.

Methods

We have developed a myoelectric untethered robotic glove (My-HERO) that provides five-finger extension and grip assistance.

Results

The myoelectric controller detected the grip and release intents of the 9 participants after stroke with 84.7% accuracy. While using My-HERO, all 9 participants performed better on the Fugl-Meyer Assessment-Hand (8.4 point increase, scale out of 14, p < 0.01) and the Chedoke Arm and Hand Activity Inventory (8.2 point increase, scale out of 91, p < 0.01). Established criteria for clinically meaningful important differences were surpassed for both the hand function and daily living task assessments. The majority of participants provided satisfaction and usability questionnaire scores above 70%. Seven participants desired to use My-HERO in the clinic and at home during their therapy and daily routines.

Conclusions

People with hand impairment after stroke value that myoelectric untethered robotic gloves enhance their motion and bimanual task performance and motivate them to use their muscles during engaging activities of daily living. They desire to use these gloves daily to enable greater independence and investigate the effects on neuromuscular recovery.

Design of a 3D printed hybrid mechanical structure for a hand exoskeleton

Stroke survivors often have difficulty performing activities of daily living (ADLs) due to hand impairments. Several assistive devices have been developed for stroke survivors to assist them with ADLs but most of these devices are difficult to don and doff for a stroke survivor due to highly flexed postures of the wrist and digits. This paper presents a hybrid 3D printed mechanical structure for an assistive hand exoskeleton created for stroke survivors. The design facilitates donning and doffing of the assistive exoskeleton by enabling an approach entirely from the dorsal side of the hand, thereby allowing the fingers to stay flexed. The design criteria, resulting design and the prototype development are presented. The initial prototype of the structure, using a hybrid combination of rigid and flexible materials, was lightweight (only 185 g), while maintaining a high range of motion. Future directions for further improvements and user studies are described.

Soft Exoskeleton Glove with Human Anatomical Architecture: Production of Dexterous Finger Movements and Skillful Piano Performance

This article developed and assessed a novel soft exoskeleton glove generating dexterous finger joint movements with little constraints on volitional motions. Four pneumatic artificial muscles were attached to each finger, which formed two antagonistic pairs of muscles similar to the human anatomy, and thereby, enabled various postural control of the individual joints. This unique structure provided 20 DOFs with the exoskeleton. A unique adjustable mechanism also allowed for fixing the soft exoskeleton suitable for user's hand shape and size semi-automatically. Our glove generated static force of approximately 8 N at the fingertip, and moved a single finger at approximately 10 Hz and all five digits sequentially at 25 Hz. Through co-contracting the antagonistic muscles, the fingertip force generated by the tapping was increased by 1.5 times. Compared with hard exoskeleton gloves, our soft exoskeleton glove had lower constraints on the volitional finger motions performed by pianists, and also enabled to passively move the fingers quicker. Finally, after the soft exoskeleton passively moved the fingers so as to play a musical excerpt with the piano over a half hour, force variability of the keypresses was reduced when playing even without wearing the glove. Passive movement guidance by the soft exoskeleton may facilitate fine control of sequential force production.

Preliminary Results in Testing of a Novel Asymmetric Underactuated Robotic Hand Exoskeleton for Motor Impairment Rehabilitation

Robotic exoskeletons are a trending topic in both robotics and rehabilitation therapy. The research presented in this paper is a summary of robotic exoskeleton development and testing for a human hand, having application in motor rehabilitation treatment. The mechanical design of the robotic hand exoskeleton implements a novel asymmetric underactuated system and takes into consideration a number of advantages and disadvantages that arose in the literature in previous mechanical design, regarding hand exoskeleton design and also aspects related to the symmetric and asymmetric geometry and behavior of the biological hand. The technology used for the manufacturing and prototyping of the mechanical design is 3D printing. A comprehensive study of the exoskeleton has been done with and without the wearer’s hand in the exoskeleton, where multiple feedback sources are used to determine symmetric and asymmetric behaviors related to torque, position, trajectory, and laws of motion. Observations collected during the experimental testing proved to be valuable information in the field of augmenting the human body with robotic devices.

Preliminary Assessment of a Hand and Arm Exoskeleton for Enabling Bimanual Tasks for Individuals With Hemiparesis

The design and preliminary assessment of a semi-powered hand and arm exoskeleton is described. The exoskeleton is designed to enable bimanual activities of daily living for individuals with chronic, upper-limb hemiparesis resulting from stroke. Specifically, the device augments the user's grasp strength and ability to extend the affected hand for bimanual tasks and supplements wrist and elbow stability while conducting these tasks. The exoskeleton is battery-powered and self-contained with all electronics and power units placed within the device structure. A preliminary assessment of the exoskeleton was performed with three subjects having right-sided upper-limb motor deficit resulting from stroke. For subjects with limited hand and arm functionality, the exoskeleton increased grasp strength and improved the ability to perform representative bimanual tasks.

Design Criteria of Soft Exogloves for Hand Rehabilitation-Assistance Tasks

This paper establishes design criteria for soft exogloves (SEG) to be used as rehabilitation or assistance devices. This research consists in identifying, selecting, and grouping SEG features based on the analysis of 91 systems that have been proposed during the last decade. Thus, function, mobility, and usability criteria are defined and explicitly discussed to highlight SEG design guidelines. Additionally, this study provides a detailed description of each system that was analysed including application, functional task, palm design, actuation type, assistance mode, degrees of freedom (DOF), target fingers, motions, material, weight, force, pressure (only for fluids), control strategy, and assessment. Such characteristics have been reported according to specific design methodologies and operating principles. Technological trends are contemplated in this contribution with emphasis on SEG design opportunity areas. In this review, suggestions, limitations, and implications are also discussed in order to enhance future SEG developments aimed at stroke survivors or people with hand disabilities.

A pilot study on the design and validation of a hybrid exoskeleton robotic device for hand rehabilitation

STUDY DESIGN

An iterative design process was used to obtain design parameters that satisfy both kinematic and dynamic requirements for the hand exoskeleton. This design was validated through experimental studies.

INTRODUCTION

The success of hand rehabilitation after impairments depends on the timing, intensity, repetition, and frequency, as well as task-specific training. Considering the continuing constraints placed on therapist-led rehabilitation and need for better outcomes, robot-assisted rehabilitation has been explored. Soft robotic approaches have been implemented for a hand rehabilitation exoskeleton as they have more tolerance for alignment with biological joints than those of hard exoskeletons.

PURPOSE OF THE STUDY

The purpose of the study was to design, develop, and validate a soft robotic exoskeleton for hand rehabilitation.

METHODS

A motion capture system validated the kinematics of the soft robotic digit attached on top of a human index finger. A pneumatic control system and algorithms were developed to operate the exoskeleton based on three therapeutic modes: continuous passive, active assistive, and active resistive motion. Pilot studies were carried out on one healthy and one poststroke participant using continuous passive motion and bilateral/bimanual therapy modes.

RESULTS

The soft robotic digits were able to produce required range of motion and accommodate for dorsal lengthening, with trajectories of the center of rotation of the soft robotic joints in close agreement with the center of rotation of the human finger joints.

DISCUSSION

The exoskeleton showed the robust performance of the robot in applying continuous passive motion and bilateral/bimanual therapy.

CONCLUSIONS

This soft robotic exoskeleton is promising for assisting in the rehabilitation of the hand.

Hand Extension Robot Orthosis (HERO) Grip Glove: enabling independence amongst persons with severe hand impairments after stroke

BACKGROUND

The Hand Extension Robot Orthosis (HERO) Grip Glove was iteratively designed to meet requests from therapists and persons after a stroke who have severe hand impairment to create a device that extends all five fingers, enhances grip strength and is portable, lightweight, easy to put on, comfortable and affordable.

METHODS

Eleven persons who have minimal or no active finger extension (Chedoke McMaster Stage of Hand 1-4) post-stroke were recruited to evaluate how well they could perform activities of daily living and finger function assessments with and without wearing the HERO Grip Glove.

RESULTS

The 11 participants showed statistically significant improvements (p < 0.01), while wearing the HERO Grip Glove, in the water bottle grasp and manipulation task (increase of 2.3 points, SD 1.2, scored using the Chedoke Hand and Arm Inventory scale from 1 to 7) and in index finger extension (increase of 147o, SD 44) and range of motion (increase of 145o, SD 36). The HERO Grip Glove provided 12.7 N (SD 8.9 N) of grip force and 11.0 N (SD 4.8) of pinch force to their affected hands, which enabled those without grip strength to grasp and manipulate blocks, a fork and a water bottle, as well as write with a pen. The participants were 'more or less satisfied' with the HERO Grip Glove as an assistive device (average of 3.3 out of 5 on the Quebec User Evaluation of Satisfaction with Assistive Technology 2.0 Scale). The highest satisfaction scores were given for safety and security (4.6) and ease of use (3.8) and the lowest satisfaction scores were given for ease of donning (2.3), which required under 5 min with assistance. The most common requests were for greater grip strength and a smaller glove size for small hands.

CONCLUSIONS

The HERO Grip Glove is a safe and effective tool for enabling persons with a stroke that have severe hand impairment to incorporate their affected hand into activities of daily living, which may motivate greater use of the affected upper extremity in daily life to stimulate neuromuscular recovery.

Soft Rehabilitation and Nursing-Care Robots: A Review and Future Outlook

Rehabilitation and nursing-care robots have become one of the prevalent methods for assistant treatment of motor disorder patients in the field of medical rehabilitation. Traditional rehabilitation robots are mostly made of rigid materials, which significantly limits their application for medical rehabilitation and nursing-care. Soft robots show great potential in the field of rehabilitation robots because of their inherent compliance and safety when they interact with humans. In this paper, we conduct a systematic summary and discussion on the soft rehabilitation and nursing-care robots. This study reviews typical mechanical structures, modeling methods, and control strategies of soft rehabilitation and nursing-care robots in recent years. We classify soft rehabilitation and nursing-care robots into two categories according to their actuation technology, one is based on tendon-driven actuation and the other is based on soft intelligent material actuation. Finally, we analyze and discuss the future directions and work about soft rehabilitation and nursing-care robots, which can provide useful guidance and help on the development of advanced soft rehabilitation and nursing-care robots.