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This research presents a novel hand exoskeleton rehabilitation device to facilitate tendon therapy exercises. The exoskeleton is designed to assist fingers flexion and extension motions in a natural manner. The proposed multi-Degree Of Freedom (DOF) system consists of a direct-driven, optimized and underactuated serial linkage mechanism having capa...
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Context 1
... closed-loop position control (Fig. 8) is based on the minimum jerk trajectory generation. Based on desired refer- ence position and position sensed by the motor encoders, the control logic generates Proportional (P), Integrator (I) and Differentiator (D) gain coefficients. After limiting the overall coefficients, the power driver drives the motors of the device. The ...
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... x 1 ( t ) is a particular trajectory starting at time t 1 and ending at time t 2 . The function that most smoothly connects a starting point to a target in a given amount of time has the minimum value of the JCF. Thus by minimizing the area under this curve, a human-like trajectory has been obtained for the proposed exoskeleton device. To execute the control strategy, a distributed control system ( Fig. 7) working in a client-server mode has been implemented. The on-board controller functions as a 'server' while a dedicated laptop serves the role of a 'client'. The realized control system offers the execution of high as well as low level commands. The controller is based on a Freescale DSP (56F807) and is made up of two components (logic and power). The Controller Area Network (CAN) bus is employed to interface the controller with the application running on the laptop. The closed-loop position control (Fig. 8) is based on the minimum jerk trajectory generation. Based on desired reference position and position sensed by the motor encoders, the control logic generates Proportional ( P ), Integrator ( I ) and Differentiator ( D ) gain coef fi cients. After limiting the overall coef fi cients, the power driver drives the motors of the device. The encoder data is sent as a feedback to close the control loop. Using the results obtained both from the optimization procedure and human hand maximum force level measure- ment experiments, the fi rst prototype of the rehabilitation system has been developed. The prototype consists of a linkage mechanism each for thumb and index fi nger. The rehabilitation scheme of the remaining three fi ngers is same as that of index fi nger owing to their similarly. Each fi nger of the device is actuated with a separate DC brush motor (Maxon RE 25). Use of low reduction gearbox for the motor permits back-drivability of each exoskeleton fi nger. The device provides active DOF for fl exion/extension motion while rotation of the motors on ball bearings around the vertical axis permits passive DOF for abduction/adduction motion. The CAD model of the proposed exoskeleton system is illustrated in Fig. 9. Most of the custom designed parts have been fabricated using light aluminum while miniature components (e.g. lockers, pins) are made up of steel. The base of the robot is made up of ABS-plastic for weight reduction. The fabricated prototype of the two- fi ngered robotic system is shown in Fig. 10 while Table 4 summarizes key speci fi cations of the system. A key feature of the presented rehabilitation device concerns the design and control of the direct-driven mechanism. For guidance during rehabilitation or training, the control should have the capability to follow the desired movements or trajectories as dictated by physiotherapists. The device has been subjected to various reference inputs including step, ramp, sinusoidal etc. to investigate the dynamic characteristics of the system and to analyze the control scheme. The capability of control to track these inputs has been observed. Two cases have been considered: (i) Free motion (ii) constrained motion. In the fi rst case, the device moves without encountering any object while in constrained case, a rubber glove packed with sponge has been used to test the device. For each reference input, fi ve sets of readings of the motor encoder data have been recorded. For step input, the duration of the experiment was 3 s. The time course of the active joint angle of the rehabilitation device and the reference input is illustrated in Fig. 11(a) for the free motion case. The joint angle converges to its reference signal (dotted line). The deviation is very small depicting that the joint motion is reproducible. The rise time observed from the averaged data is 0.22 s. For constrained case, step response of the device is shown in Fig. 11(b). In terms of physical values, this plot resembles signi fi cantly with the response illustrated in Fig. 11 (a) implying high reproducibility. The joint angles can closely track the desired signal. The rise time in this case is 0.33 s. This value is different from the rise time in the fi rst case due to the rubber elasticity. Exercises using a rehabilitation device essentially include execution of fi nger fl exion-extension cycles. This, in terms of control, means tracking a sinusoidal trajectory. Fig. 12(a) and (b) shows the sinusoidal response of the proposed device in case of free movement and constrained motion respectively. As illustrated, the joint angles can continu- ously track the time-varying reference input in their close proximity. Another experiment addressed the control performance in case of a user wearing the exoskeleton device. In this self- motion control case, the objective was to evaluate the ability of the system in sustaining a constraint. The user varied the applied force while the controller has been set to ensure a constant position. In view of the fact that the proposed rehabilitation device can provide bidirectional forces, a bidirectional constraint was applied. Fig. 13 illustrates the position control response of the system. This paper presents a novel hand exoskeleton based rehabilitation device that is aimed at patients' recovery during post-stroke activities by practicing fi ngers fl exion and extension. Based on the proposed direct-driven under-actuated mechanism, the device design has been supported by optimization results, derivation of design requirements, modeling and control algorithm. Such a mechanism based on the direct transmission of force/torque offers several advantages over tendon-driven systems. The mechanism does not require continuous control of cable tensioning and avoids issues arising because of intrinsic friction. The direct driven devices also exhibit other bene fi ts in terms of wide stiffness range and enhanced force bandwidth as compared with cable based systems because the later act as a stiff spring thus limiting end-effector stiffness. Other features that make the present work distinguishing among existing systems include human hand compatibility, portability, less complexity and easy removal/donning. The proposed rehabilitation device provides adequate force levels for executing ADL. Trying to match the human hand capabilities resulted in a device with natural ROM and force levels (of 45 N) beyond any existing system's capability. Being a portable system, the presented device has a great potential in prosthetics as well as for assistance. The comfort, because of ease in fi tting adjustment and removal, permits the extended use of the system without causing fatigue to the wearer even after long periods (e.g. 1 – 2 h of operation). The pilot study based on series of experiments indicates that the device has the capability to move the fi nger digits and to track various trajectories. Nearly every possible motion trajectory can be followed with adequate accuracy. The device provides position feedback as well as offers monitoring of forces exerted by the wearer during rehabilitation. These feedbacks are quantitative indicators of recovery and can facilitate physical therapy plans. More clinical trials are intended to further access the device performance. With the help of rehabilitation professionals, we are currently developing rehabilitation strategies to test the exoskeleton on patients after meeting medical safety standards. The proposed device is anticipated to have a great potential in rehabilitation of the impaired hand. In addition to rehabilitation, the proposed exoskeleton, owing to its portability, can also fi nd application as an assistive device. Translating the requirement of maximum force strength of a human hand in the device design by appropriate actuator selection resulted in a system exhibiting higher force levels (45 N) beyond any existing rehabilitation device. However, in our daily life, it is quite seldom that we need such huge force levels. To enhance the portability of the exoskeleton, it is simple to substitute the current actuators with smaller ones for reducing weight and size while still providing enough force levels for many of the daily life applications. Future work includes developing strategies to control the exoskeleton through brain signals and to fi nally integrate the device in a wheelchair based robot for outdoor use [40]. Italian Institute of Technology (IIT), University of Genova provided funding and required resources to conduct this research, while COMSATS, Islamabad, Pakistan provided support for preparation of this article. The authors would like to extend their thanks to Dr. Emanuele and therapists at Ospedale San Martino, Genoa for their valuable comments and suggestions. Thanks to University of Genova for providing funding and required resources for this research. Special regards to Dr. Muhammad Fasih Uddin Butt, Director of Modeling and Simulation Lab. at CIIT, Islamabad, Pakistan to provide resources and environment to facilitate the write-up of this manuscript. Based on the determined DH parameters (Table 2) and using the general form of Transformation matrix ...
Citations
... For instance, the Apex Alpha [7] is pneumatic actuated exoskeleton that assist the elbow joints. Other assistive robots like HAL [8], Vanderbilt [9], REX [10], HES Hand [11], ReWalk [12], HandeXos-Beta [13], HandSOME [14], and HexoSYS [15] utilize motors and tendons to aid activities of daily life (ADLs) such as climbing stair, balancing, grasping, pouring liquids, and buttoning. These robots have been proven to be effective in augmenting human strength, and aids in stroke rehabilitation [12]. ...
Soft actuators and robotic devices designed for rehabilitation and assistance are a rapidly growing field of research. Their inherent flexibility enhances comfort and usability without restricting the user’s natural range of motion. However, despite these advantages, there are still several challenges that need to be addressed before these systems can be commercialized. This paper presents a comprehensive review of the latest developments in soft wearable robots, also known as exosuits. Soft exosuits are composed of two main components: actuation mechanisms (how forces/torques are generated) and physical interfaces (how and where the robot is anchored to the body). This paper reviews the advances in these two areas, while categorizing exosuits based on the intended assisted joint, assisted degrees of freedom (DOF), and device type. The systematic literature review follows the PRISMA guidelines to summarize the relevant studies and investigate their related physical interface, actuation mechanism and its design. Several limitations were identified in these areas, and insights into potential future research directions are presented. In the future, the goal should be to develop an untethered assistive device that can provide assistance to multiple joints while having a low form factor, an intuitive and natural interface, and being comfortable for the user.
... Other devices were designed for poststroke patients to aid in hand and ankle movements [34,35]. Also works by Iqbal et al. and Conti et al. focused on hand rehabilitation and assistance [36,37]. However, these studies involve the use of bulky pneumatic pumps to actuate the actuators, which adds extra weight to the devices, potentially affecting their practicality and comfort. ...
Rehabilitation of the upper and lower limbs is crucial for patients recovering from strokes, surgeries, or injuries. Traditional rehabilitation often takes place in hospitals under the guidance of a therapist, which can delay treatment due to various constraints. This paper proposes a soft robotic device designed to aid in the flexion and extension of both the elbow and knee. The device utilizes pneumatic artificial muscles, constructed from an elastomeric bladder with a threaded mesh exterior, as its actuating mechanism. It operates in two distinct modes: a continuous passive mode, where continuous, repetitive flexion, and extension of limbs are carried out, and an active intent-based assisted mode, which detects a patient's movement intention via surface electromyography (sEMG) and subsequently aids in the movement execution. To test the effectiveness of the device, sEMG electrodes were placed on upper and lower limbs of six healthy male subjects, range of motion, and muscle activity were recorded with and without the device. Also NASA task load index (NASA-TLX) was calculated for the usability of the device. The results indicate the required muscle activity and range of motions for both upper and lower limb rehabilitation are effectively generated in both the modes.
... In this context, two main types of actuation can be distinguished: direct drive and geared systems. Direct drive refers to systems where the actuators are directly connected to the structure [22][23][24][25][26][27][28][29][30][31][32], while geared systems use a gear train to connect the actuator to the structure [33][34][35][36][37]. In fewer applications, the two approaches are merged [38]. ...
... These structures can actuate multiple DOFs simultaneously, in a controlled manner, using a single actuator. Based on this concept, different transmission systems can be identified: four-bar linkage mechanisms [23,31,[41][42][43][44], remote center of rotation [22,28,45], serial links mechanisms (suitable if the device needs to fit various users) [24,27,34,36], and matchedaxis mechanical structures [46][47][48]. Each of these proposed solutions allows the actuation of the hand DOFs while maintaining the device's portability and functionality. ...
... DC motors are the most widely used due to their ease of use, backdrivability, and low torques at high speeds. Therefore, these types of motors are accompanied by a gearbox to increase the torque by reducing the motor speed [24,28,[34][35][36]38,46,47,50]. Linear actuators are another type of system employed in rigid hand exoskeleton actuation units [22,23,25,29,32,40,51,52]. ...
In recent decades, extensive attention has been paid to the study and development of robotic devices specifically designed for hand rehabilitation. Accordingly, a many concepts concerning rigid, soft, and hybrid types have emerged in the literature, with significant ongoing activity being directed towards the development of new solutions. In this context, the paper focuses on the technical features of devices conceived for the robotic rehabilitation of the hand with reference to the three kinds of exoskeleton architecture and the clinical requirements demanded by the target impairment of the end-user. The work proposes a roadmap (i) for both the design and selection of exoskeletons for hand rehabilitation, (ii) to discriminate among the peculiarities of soft, rigid, and hybrid devices, and (iii) with an impairment-oriented rationale. The clinical requirements expected for an exoskeleton are identified by applying a PICO-inspired approach focused on the impairment analysis; the technical features are extracted from a proposed design process for exoskeletons combined with a narrative literature review. A cross-analysis between device families and features is presented to provide a supporting tool for both the design and selection of exoskeletons according to an impairment-oriented rationale.
... A few studies on rigid link-based hand exoskeletons have reported to adopt the base-to-distal mechanism in their design [28]- [31]. Unfortunately, most of them are still in their pilot stage with only F/E motions for two or three fingers [28], [29], [31], or for five fingers with one actuator [30]. Furthermore, none of these designs have yet considered the thumb Ab/Ad motions, which are critically important for hand functions. ...
p>Hand exoskeletons are wearable devices that can provide outer kinematic coupling with human hands and thus assist movement of human fingers. However, conventional rigid hand exoskeletons are characterized by their bulky and complex structures, which are often incompatible with human finger joints and restrict finger’s natural motion. This paper reports an underactuated base-to-distal hand exoskeleton that provides adaptive grasping assistance. An underactuated 8-bar base-to-distal linkage driven by a cable is used to flex and extend fingers and it applies force only to the distal phalanges of fingers, which not only makes the hand exoskeleton adapt to different sizes of fingers but also allows all phalanges to naturally accommodate the geometry of the objects to be grasped. The kinematic model of the 8-bar linkage is derived in order to generate desired hand ges-tures. A five-finger hand exoskeleton with active flexion/extension (F/E) for all fingers and active abduction/adduction (Ab/Ad) for the thumb is assembled and then tested on a healthy subject and a stroke survivor. Experimental results show that the hand exoskeleton can generate sufficient fingertip force for regular tasks. The hand exoskeleton enables the healthy participant and the stroke survivor to achieve 90% and 52% of their passive range of F/E motions respectively. In addition, the stroke survivor can accomplish various training tasks, such as grasping, pinching and writing, with the assistance of the hand exoskeleton. These results demonstrate that the underactuated base-to-distal hand exoskeleton can be an effective device for rehabilitation training or daily-life assistance for patients with a hemiparetic hand.</p
... A few studies on rigid link-based hand exoskeletons have reported to adopt the base-to-distal mechanism in their design [28]- [31]. Unfortunately, most of them are still in their pilot stage with only F/E motions for two or three fingers [28], [29], [31], or for five fingers with one actuator [30]. Furthermore, none of these designs have yet considered the thumb Ab/Ad motions, which are critically important for hand functions. ...
p>Hand exoskeletons are wearable devices that can provide outer kinematic coupling with human hands and thus assist movement of human fingers. However, conventional rigid hand exoskeletons are characterized by their bulky and complex structures, which are often incompatible with human finger joints and restrict finger’s natural motion. This paper reports an underactuated base-to-distal hand exoskeleton that provides adaptive grasping assistance. An underactuated 8-bar base-to-distal linkage driven by a cable is used to flex and extend fingers and it applies force only to the distal phalanges of fingers, which not only makes the hand exoskeleton adapt to different sizes of fingers but also allows all phalanges to naturally accommodate the geometry of the objects to be grasped. The kinematic model of the 8-bar linkage is derived in order to generate desired hand ges-tures. A five-finger hand exoskeleton with active flexion/extension (F/E) for all fingers and active abduction/adduction (Ab/Ad) for the thumb is assembled and then tested on a healthy subject and a stroke survivor. Experimental results show that the hand exoskeleton can generate sufficient fingertip force for regular tasks. The hand exoskeleton enables the healthy participant and the stroke survivor to achieve 90% and 52% of their passive range of F/E motions respectively. In addition, the stroke survivor can accomplish various training tasks, such as grasping, pinching and writing, with the assistance of the hand exoskeleton. These results demonstrate that the underactuated base-to-distal hand exoskeleton can be an effective device for rehabilitation training or daily-life assistance for patients with a hemiparetic hand.</p
... There has been significant progress in designing and developing robotic hand exoskeletons for rehabilitation, and assistive tasks (more than fifty soft hand exoskeletons have been developed over the past 15 years [12,13,16]). Soft robotics provides potential solutions to address the complex mechanisms, heavy weight, bulky size, high cost, and safety issues involved in conventional (rigid) robots [4,9,13,[17][18][19][20]. Three major groups of soft robotic hand exoskeletons have emerged: (1) fluid-actuated elastomeric/textile-fabric robots (e.g., the pneumatic artificial muscle-based gloves [15,21], Harvard's soft robotic glove [9,22], fabric-based gloves [23-25], elastomeric gloves [26-30]); (2) cable/tendondriven robots (e.g., GraspyGlove [31], and Exo-Glove Poly [32,33]); and (3) hybrid softand-rigid robots (e.g., REHAB Glove developed at UTARI [10,11,14,34], Exo-Glove PM [35] developed at SNU, and SeptaPose Assistive and Rehabilitation (SPAR) developed at Rice University [20] ...
This paper presents a quasi-static model-based control algorithm for controlling the motion of a soft robotic exo-digit with three independent actuation joints physically interacting with the human finger. A quasi-static analytical model of physical interaction between the soft exo-digit and a human finger model was developed. Then, the model was presented as a nonlinear discrete-time multiple-input multiple-output (MIMO) state-space representation for the control system design. Input-output feedback linearization was utilized and a control input was designed to linearize the input-output, where the input is the actuation pressure of an individual soft actuator, and the output is the pose of the human fingertip. The asymptotic stability of the nonlinear discrete-time system for trajectory tracking control is discussed. A soft robotic exoskeleton digit (exo-digit) and a 3D-printed human-finger model integrated with IMU sensors were used for the experimental test setup. An Arduino-based electro-pneumatic control hardware was developed to control the actuation pressure of the soft exo-digit. The effectiveness of the controller was examined through simulation studies and experimental testing for following different pose trajectories corresponding to the human finger pose during the activities of daily living. The model-based controller was able to follow the desired trajectories with a very low average root-mean-square error of 2.27 mm in the x-direction, 2.75 mm in the y-direction, and 3.90 degrees in the orientation of the human finger distal link about the z-axis.
... The movement performed by upper limbs, especially the hand, is more complicated as hand movements, such as grasp or pinch, are mediated by a combination of multiple small-joint movements, including interphalangeal, metacarpophalangeal, intercarpal, radiocarpal, and radioulnar joint [23,24]. Compared to the movement of lower limbs, these upper-limb movements cannot be fully supported by upper-limb robots [25][26][27][28][29], therefore the current upper limb RAT is less effective as compared with lower limb RAT. ...
Background:
Stroke and spinal cord injury are neurological disorders that cause disability and exert tremendous social and economic effects. Robot-assisted training (RAT), which may reduce spasticity, is widely applied in neurorehabilitation. The combined effects of RAT and antispasticity therapies, such as botulinum toxin A injection therapy, on functional recovery remain unclear. This review evaluated the effects of combined therapy on functional recovery and spasticity reduction.
Materials and methods:
Studies evaluating the efficacy of RAT and antispasticity therapy in promoting functional recovery and reducing spasticity were systemically reviewed. Five randomized controlled trials (RCTs) were included. The modified Jadad scale was applied for quality assessment. Functional assessments, such as the Berg Balance Scale, were used to measure the primary outcome. Spasticity assessments, such as the modified Ashworth Scale, were used to measure the secondary outcome.
Results:
Combined therapy improves functional recovery in the lower limbs but does not reduce spasticity in the upper or lower limbs.
Conclusions:
The evidence supports that combined therapy improves lower limb function but does not reduce spasticity. The considerable risk of bias among the included studies and the enrolled patients who did not receive interventions within the golden period of intervention are two major factors that should be considered when interpreting these results. Additional high-quality RCTs are required.
... In both cases the device is used in haptic application that focused on bidirectional force feedback. However, rehabilitation devices require multi DOF for the training of the human hand and exerting forces at the distal phalanx has limited control over the proximal or middle phalanx [7]. The underactuated mechanism which reduces the requirement of actuator attaches the system either at the proximal or middle segment of the finger. ...
This paper outlines a method to design an underactuated, linkage-based hand exoskeleton. A planar 8-link mechanism with phalanges and articulations as part of the kinematic chain is used for each finger. The links are attached to the proximal and distal phalanges. For the thumb, a planar 6-link mechanism directly connected at the distal phalanx is used. The kinematic synthesis of the mechanism based on Burmester Theory was performed with two principal considerations: a. To obtain link lengths that ensured no mechanical interference between the mechanisms and the hand and b. The mechanism ensured that each finger follows the natural trajectory. The mechanism is evaluated by comparing the workspace of the anatomical index finger with that of the hand exoskeleton assisted finger.
... However, the use of an exoskeleton system in therapy is still limited, as only a small subset makes it into clinical testing or practice due to the complexity and resulting in poor usability in a clinical context [5]. Numerous exoskeletons have been developed, often requiring a direct fit to the patient's hand [13][14][15], or providing an adaptive actuation [6,16,17]. Often, these concepts do not provide sufficient sensor applications and lack sufficient force sensing or cannot distinguish between the movements of MCP, PIP, and DIP joints. ...
This paper presents the application of an adaptive exoskeleton for finger rehabilitation.
The system consists of a force-controlled exoskeleton of the finger and wireless coupling to a mobile application for the rehabilitation of complex regional pain syndrome (CRPS) patients. The exoskeleton has sensors for motion detection and force control as well as a wireless communication module. The proposed mobile application allows to interactively control the exoskeleton, store collected patient-specific data, and motivate the patient for therapy by means of gamification. The exoskeleton was applied to three CRPS patients over a period of six weeks. We present the design of the exoskeleton, the mobile application with its game content, and the results of the performed preliminary patient study. The exoskeleton system showed good applicability; recorded data can be used for objective therapy evaluation.
... Furthermore, rehabilitation robotics allows self-treatment with remote supervision of several patients by a single therapist [1,2]. The hands offer autonomy to people's lives by providing physical interaction and grasping capabilities [3]. According to [3], developing countries are home to 80 percent of disabled people. ...
... The hands offer autonomy to people's lives by providing physical interaction and grasping capabilities [3]. According to [3], developing countries are home to 80 percent of disabled people. This is because they are poor countries and have difficulty accessing rehabilitation services. ...
... This is because they are poor countries and have difficulty accessing rehabilitation services. Therefore, these countries need low-cost robotic devices that can help them in the rehabilitation process, which could help people with disabilities, as also stated in [3]. ...
Robot rehabilitation devices are attracting significant research interest, aiming at developing viable solutions for increasing the patient’s quality of life and enhancing clinician’s therapies. This paper outlines the design and implementation of a low-cost robotic system that can assist finger motion rehabilitation by controlling and adapting both the position and velocity of fingers to the users′ needs. The proposed device consists of four slider-crank mechanisms. Each slider-crank is fixed and moves one finger (from the index to the little finger). The finger motion is adjusted through the regulation of a single link length of the mechanism. The trajectory that is generated corresponds to the natural flexion and extension trajectory of each finger. The functionality of this mechanism is validated by experimental image processing. Experimental validation is performed through tests on healthy subjects to demonstrate the feasibility and user-friendliness of the proposed solution.
