Hand Exoskeleton For Rehabilitation Research Articles

A Review on Soft Exoskeletons for Hand Rehabilitation

Background: How to enhance the quality of life for the elderly has emerged as a key issue in many nations due to the ageing population. Stroke is the most prevalent disease among the elderly; specifically, the hand dysfunction caused by stroke is also a powerful obstacle to the daily life of the elderly. Soft Exoskeletons for Hand Rehabilitation (SEHRs) have become a major trend for the future due to the increasing demand for hand rehabilitation. Objective: To provide a reference for readers in this field by introducing the most recent research developments in the field of SEHR, including their classification and properties. Methods: By reviewing different types of hand rehabilitation exoskeleton research papers and patents, the advantages and disadvantages, differences, and applications of various SEHRs were summarized. Results: According to the driving mode and realizing the function of SEHRs, the structure characteristics of SEHRs are analyzed and compared. The key problems and future development trends of SEHRs were expounded. Conclusion: According to the driving method, the research shows that SEHRs can be divided into Air-Driven Soft Exoskeletons for Hand Rehabilitation (ADSEHRs), Motor-Driven Soft Exoskeletons for Hand Rehabilitation (MDSEHRs), and Hybrid-Driven Soft Exoskeletons for Hand Rehabilitation (HDSEHRs). Future research is required to further optimize the flexibility and adaptability of soft exoskeletons, improve their accuracy and sensitivity, and enhance human-machine interaction with the human hand.

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.

Gear-based Multimodal Underdriven Index Finger Exoskeleton Rehabilitation Device

With the increase of stroke patients, wearable hand rehabilitation exoskeleton devices used to do mechanical rehabilitation training have received attention from researchers. Most of the rigid hand exoskeletons can only perform simple flexion and extension training of the finger as a whole, and not single joint training. Therefore, the subject of this paper is to develop a new multimodal underdriven index finger exoskeleton based on gear drive. The data analysis is compared to achieve the desired specific gesture. This device allows the user to further train the finger and also helps the medical practitioner to better determine the individual joint function of the patient.

Interaction with a Hand Rehabilitation Exoskeleton in EMG-Driven Bilateral Therapy: Influence of Visual Biofeedback on the Users' Performance.

The effectiveness of EMG biofeedback with neurorehabilitation robotic platforms has not been previously addressed. The present work evaluates the influence of an EMG-based visual biofeedback on the user performance when performing EMG-driven bilateral exercises with a robotic hand exoskeleton. Eighteen healthy subjects were asked to perform 1-min randomly generated sequences of hand gestures (rest, open and close) in four different conditions resulting from the combination of using or not (1) EMG-based visual biofeedback and (2) kinesthetic feedback from the exoskeleton movement. The user performance in each test was measured by computing similarity between the target gestures and the recognized user gestures using the L2 distance. Statistically significant differences in the subject performance were found in the type of provided feedback (p-value 0.0124). Pairwise comparisons showed that the L2 distance was statistically significantly lower when only EMG-based visual feedback was present (2.89 ± 0.71) than with the presence of the kinesthetic feedback alone (3.43 ± 0.75, p-value = 0.0412) or the combination of both (3.39 ± 0.70, p-value = 0.0497). Hence, EMG-based visual feedback enables subjects to increase their control over the movement of the robotic platform by assessing their muscle activation in real time. This type of feedback could benefit patients in learning more quickly how to activate robot functions, increasing their motivation towards rehabilitation.

Development and Validation of a System for the Assessment and Recovery of Grip Force Control.

The ability to finely control hand grip forces can be compromised by neuromuscular or musculoskeletal disorders. Therefore, it is recommended to include the training and assessment of grip force control in rehabilitation therapy. The benefits of robot-mediated therapy have been widely reported in the literature, and its combination with virtual reality and biofeedback can improve rehabilitation outcomes. However, the existing systems for hand rehabilitation do not allow both monitoring/training forces exerted by single fingers and providing biofeedback. This paper describes the development of a system for the assessment and recovery of grip force control. An exoskeleton for hand rehabilitation was instrumented to sense grip forces at the fingertips, and two operation modalities are proposed: (i) an active-assisted training to assist the user in reaching target force values and (ii) virtual reality games, in the form of tracking tasks, to train and assess the user's grip force control. For the active-assisted modality, the control of the exoskeleton motors allowed generating additional grip force at the fingertips, confirming the feasibility of this modality. The developed virtual reality games were positively accepted by the volunteers and allowed evaluating the performance of healthy and pathological users.

Mechanism Design and Performance Analysis of a Wearable Hand Rehabilitation Robot

Hand rehabilitation is critical to the recovery of post-stroke patients. However, designing a modular mechanism of the hand to improve the human-machine compatibility and precision of operation is still a challenge. This paper proposes a new type of hand exoskeleton rehabilitation robot with nine degrees of freedom. With the flexible rods, the passive range of motion for finger adduction/abduction is extended under the premise of independent flexion/extension of the metacarpophalangeal and proximal interphalangeal joint. Based on hand anatomy, the relationship between the offset of the metacarpophalangeal joint and the body height in the process of flexion and extension is discussed, and it is applied to the structure optimization and control system. The genetic algorithm is employed to achieve the size optimization, and the kinematics is analyzed. Finally, a prototype is built and preliminary experiments are carried out, including the range of motion and the grasping ability of the robot. The experimental results show that the robot can realize the patients’ hand rehabilitation function and has certain adaptability.

Data-Driven Predictive Control of Exoskeleton for Hand Rehabilitation with Subspace Identification.

This study proposed a control method, a data-driven predictive control (DDPC), for the hand exoskeleton used for active, passive, and resistive rehabilitation. DDPC is a model-free approach based on past system data. One of the strengths of DDPC is that constraints of states can be added to the controller while performing the controller design. These features of the control algorithm eliminate an essential problem for rehabilitation robots in terms of easy customization and safe repetitive rehabilitation tasks that can be planned within certain constraints. Experiments were carried out with a designed hand rehabilitation system under repetitive and various therapy tasks. Real-time experiment results demonstrate the feasibility and efficiency of the proposed control approach to rehabilitation systems.

Assessment of Soft Actuators for Hand Exoskeletons: Pleated Textile Actuators and Fiber-Reinforced Silicone Actuators.

Soft robotic approaches have been trialed for rehabilitation or assistive hand exoskeletons using silicone or textile actuators because they have more tolerance for alignment with biological joints than rigid exoskeletons. Textile actuators have not been previously evaluated, and this study compares the mechanical properties of textile and silicone actuators used in hand exoskeletons. The physical dimensions, the air pressure required to achieve a full bending motion, and the forces generated at the tip of the actuator were measured and compared. The results showed that the construction method of the silicone actuators is slower than the textile actuators, but it generates better dimensional accuracy. However, the air pressure required for the actuators to generate a full bending motion is significantly lower for textile actuators, and the blocking force generated at that pressure is 35% higher in the textile actuators. There are significant differences across all variables compared, indicating that actuators constructed using pleated textile techniques have greater potential for the construction of an exoskeleton for hand rehabilitation or assistance.

Optoelectronic-Based Pose Sensing for a Hand Rehabilitation Exoskeleton Continuous Structure

Hand exoskeleton pose monitoring is of great importance in the rehabilitation training of stroke patients to ensure precise robotic trajectory control and provide a patient recovery assessment mechanism. In this paper, a low-cost pose sensor unit based on the principle of photoelectric reflection is proposed to measure the pose of a multi-segment continuous structure in a hand rehabilitation exoskeleton. The sensor unit consists of five photosensitive elements that measure the rotation angle of an arrangement of adjacent segments, each integrated with a sensing element, to estimate the actuator’s motion. An accurate device with a user-friendly interface is then designed for calibration of the sensing elements. The experimental results indicate that the sensitivity exceeds 0.047 V/° for the sensing elements, and hysteresis and repeatability errors are less than 1.1% and 1.8%, respectively. A comparison between the proposed sensor output and the results benchmarked by a VICON motion capture system demonstrates that the sensor can measure the bending angle of the multi-segment structure with a mean error of 3.23 degrees.

Development and Test of a Spasm Sensor for Hand Rehabilitation Exoskeleton

Development and Test of a Spasm Sensor for Hand Rehabilitation Exoskeleton

Real time motion intention recognition method with limited number of surface electromyography sensors for A 7-DOF hand/wrist rehabilitation exoskeleton

The functions of human hand are rich, and the motor dysfunction of hand of chronic stroke patients can be alleviated to some extent through active rehabilitation training. Hand rehabilitation exoskeleton can assist patients to do active rehabilitation training. However, how to realize more motion with less surface electromyogrphy (sEMG) sensors, and how to realize the real-time motion intention recognition are two important issues. This paper introduces real-time motion intention recognition method with limited number of sEMG sensors for a 7-DOF wearable hand/wrist rehabilitation exoskeleton to realize the real-time motion intention recognition and rehabilitation training. Root mean square (RMS) and Bens Spiker Algorithm (BSA) features of three-channel sEMG signals are extracted, and they are mapped to seven different intention movements by combining the Bagging method. The finger structure part of the exoskeleton is composed of a rotary-spatial-spatial-rotary (RSSR) mechanism and a double-parallelogram mechanism, which makes the projection center of exoskeleton coincide with the rotation center of the hand joint. The average real-time motion intention recognition accuracy is 95.37 ± 0.97%.

Research Progress of Exoskeleton for Hand Rehabilitation following stroke

Based on the hand rehabilitation exoskeleton, the research results of three driving modes in recent years, namely cable, connecting rod and pneumatic system, were classified, summarized and analyzed. Through research and analysis, the results of structural dimensions, structural degrees of freedom, drive selection scheme, control strategy and sensor selection scheme which are more suitable for human hand rehabilitation exoskeleton are obtained, which can provide reference for exoskeleton researchers.

Developing a hand sizing system for a hand exoskeleton device based on the Kansei Engineering method

This study aimed to identify the customers’ requirements for a hand rehabilitation exoskeleton device using the Kansei Engineering approach and propose improvements. The Kansei Engineering approach was used to extract the design attributes for a hand rehabilitation exoskeleton device by conducting an in-depth interview with 3 physical therapists. The Kano questionnaire survey investigated 25 participants with hand rehabilitation experience. The Kano classification results found three attractive factors and corresponded it to the design attributes of the evaluation grid method results that were suitable (size), flexible (controllability), and light (weight). The principal component analysis results indicated three components can be considered as the improvement categories; functions, structure-texture, and appearance of the hand exoskeleton device. The new functional and structural designs were proposed in a previous study. This study collects 110 male participants’ hand anthropometric data to establish a hand sizing system as a design improvement (suitable attribute). The 3D and manual measurements were obtained for 63 hand dimensions with an open palm posture. The 14 dorsal length dimensions with three bent finger postures were also manually measured. The results showed that the $${\text{MAD}}_{\text{Precision}}$$ (mean absolute difference) of 3D measurement is smaller than that of manual measurement, indicating better reproducibility of 3D scanning. The $${\text{MAD}}_{\text{Accuracy}}$$ of all dimensions are within the 1 mm of the referenced ISO 20685 criteria. Significant differences were found in the 14 dorsal hand length, showing that databases should explicitly state the aspect (dorsal or palmar) where dimensions have been of measurement. The 77 hand dimensions were taken into consideration to develop a hand sizing system using the clustering results. The two-level self-organizing map method was performed and 3 handshape types and 8 sizes were extracted. The coverage rate of the sizing system was over 85%. These results provide useful information for designing and manufacturing for hand-related products.

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

Study DesignAn 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. IntroductionThe 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 StudyThe purpose of the study was to design, develop, and validate a soft robotic exoskeleton for hand rehabilitation. MethodsA 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. ResultsThe 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. DiscussionThe exoskeleton showed the robust performance of the robot in applying continuous passive motion and bilateral/bimanual therapy. ConclusionsThis soft robotic exoskeleton is promising for assisting in the rehabilitation of the hand.

Variable impedance control of finger exoskeleton for hand rehabilitation following stroke

PurposeThe purpose of this paper is to propose a variable impedance control method of finger exoskeleton for hand rehabilitation using the contact forces between the finger and the exoskeleton, making the output trajectory of finger exoskeleton comply with the natural flexion-extension (NFE) trajectory accurately and adaptively.Design/methodology/approachThis paper presents a variable impedance control method based on fuzzy neural network (FNN). The impedance control system sets the contact forces and joint angles collected by sensors as input. Then it uses the offline-trained FNN system to acquire the impedance parameters in real time, thus realizing tracking the NFE trajectory. K-means clustering method is applied to construct FNN, which can obtain the number of fuzzy rules automatically.FindingsThe results of simulations and experiments both show that the finger exoskeleton has an accurate output trajectory and an adaptive performance on three subjects with different physiological parameters. The variable impedance control system can drive the finger exoskeleton to comply with the NFE trajectory accurately and adaptively using the continuously changing contact forces.Originality/valueThe finger is regarded as a part of the control system to get the contact forces between finger and exoskeleton, and the impedance parameters can be updated in real time to make the output trajectory comply with the NFE trajectory accurately and adaptively during the rehabilitation.

A novel hand exoskeleton with series elastic actuation for modulated torque transfer

Among wearable robotic devices, hand exoskeletons present an important and persistent challenge due to the compact dimensions and kinematic complexity of the human hand. To address these challenges, this paper introduces HandeXos-Beta (HX-β), a novel index finger-thumb exoskeleton for hand rehabilitation. The HX-β system features an innovative kinematic architecture that allows independent actuation of thumb flexion/extension and circumduction (opposition), thus enabling a variety of naturalistic and functional grip configurations. Furthermore, HX-β features a novel series-elastic actuators (SEA) architecture that directly measures externally transferred torque in real-time, and thus enables both position- and torque-controlled modes of operation, allowing implementation of both robot-in-charge and user-in-charge exercise paradigms. Finally, HX-β’s adjustable orthosis, passive degrees of freedom, and under-actuated control scheme allow for optimal comfort, robot-user joint alignment, and flexible actuation for users of various hand sizes. In addition to the mechatronic design and resulting functional capabilities of HX-β, this work presents a series of physical performance characterizations, including the position- and torque-control system performance, frequency response, end effector force, and output impedance. By each measure, the HX-β exhibited performance comparable or superior to previously reported hand exoskeletons, including position and torque step response times on the order of 0.3 s, −3 dB cut-off frequencies ranging from approximately 2.5 to 4 Hz, and fingertip output forces on the order of 4 N. During use by a healthy subject in torque-controlled transparent mode, the HX-β orthosis joints exhibited appropriately low output impedance, ranging from 0.42 to −0.042 Nm/rad at 1 Hz, over a range of functional grasps performed at real-life speeds. This combination of lab bench characterizations and functional evaluation provides a comprehensive verification of the design and performance of the HandeXos Beta exoskeleton, and its suitability for clinical application in hand rehabilitation.

Design and Development of a Portable Exoskeleton for Hand Rehabilitation.

Improvement in hand function to promote functional recovery is one of the major goals of stroke rehabilitation. This paper introduces a newly developed exoskeleton for hand rehabilitation with a user-centered design concept, which integrates the requirements of practical use, mechanical structure, and control system. The paper also evaluated the function with two prototypes in a local hospital. Results of functional evaluation showed that significant improvements were found in ARAT (P = 0.014), WMFT (P = 0.020), and FMA_WH (P = 0.021). Increase in the mean values of FMA_SE was observed but without significant difference (P = 0.071). The improvement in ARAT score reflects the motor recovery in hand and finger functions. The increased FMA scores suggest there is a motor improvement in the whole upper limb, and especially in the hand after the training. The product met patients' requirements and has practical significance. It is portable, cost-effective, easy to use and supports multiple control modes to adapt to different rehabilitation phases.

A Novel Variable Stiffness Compliant Finger Exoskeleton for Rehabilitation Based on Electromagnet Control.

In this study, we present the design of a variable stiffness finger exoskeleton for hand rehabilitation, to meet the requirements of different human users and versatile rehabilitation task. This paper describes the design principle and fabrication of the variable stiffness finger exoskeleton which combines a variable stiffness beam and a 3D printed compliant finger exoskeleton. Experimental studies have shown that by using the electromagnetic force, exoskeleton stiffness variation is achievable. Therefore, the proposed variable stiffness finger exoskeleton is capable of adapting the versatile tasks and providing a soft, wearable device for hand rehabilitation of different human users.

Konstrukcja egzoszkieletu wspomagającego rehabilitację ręki

Konstrukcja egzoszkieletu wspomagającego rehabilitację ręki

An index finger exoskeleton with series elastic actuation for rehabilitation: Design, control and performance characterization

Rehabilitation of the hands is critical for the restoration of independence in activities of daily living for individuals exhibiting disabilities of the upper extremities. There is initial evidence that robotic devices with force-control-based strategies can help in effective rehabilitation of human limbs. However, to the best of our knowledge, none of the existing hand exoskeletons allow for accurate force or torque control. In this work, we present a novel index finger exoskeleton with Bowden-cable-based series elastic actuation allowing for bidirectional torque control of the device with high backdrivability and low reflected inertia. We present exoskeleton and finger joint torque controllers along with an optimization-based offline parameter estimator. Finally, we carry out tests with the developed prototype to characterize its kinematics, dynamics, and controller performance. Results show that the device preserves the characteristics of natural motion of finger and can be controlled to achieve both exoskeleton and finger joint torque control. Finally, dynamic transparency tests show that the device can be controlled to offer minimal resistance to finger motion. Beyond the present application of the device as a hand rehabilitation exoskeleton, it has the potential to be used as a haptic device for teleoperation.