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Robotic rehabilitation is a solution for recovery from neuromuscular diseases and supports physical therapists in performing high-intensity and repetitive training activities. The main reason for the limitations of rehabilitation robot utilization is economic factors because rehabilitation robot technology requires high levels of investment and relatively costly routine operation and maintenance. To facilitate widespread adoption of rehabilitation robots, low-cost, highly compliant, and simple-to-operate robotic rehabilitation devices are required. In this study, to introduce a novel alternative solution to the aforementioned problem, a low-cost, highly transparent, single pneumatic artificial muscle (PAM) actuated robotic therapy orthosis that enables the patient to perform all training modalities is introduced. A novel control approach was developed by combining admittance control and inverse-dynamics-based compliant controls. By means of simple counterweight loads and compliant control, quasi-static movement of the orthosis for active exercises is achieved for the full operation range of PAM without any jerky transitions. A new assist-active modality named “Patient Activated Assistance” (PAAM) was introduced, in which the patient was the master, and the exercise was performed as long as the patient was active, avoiding slacking. Assistance was provided by sharing the load force in accordance with the applied gain. The orthosis performance in realizing the training modalities was verified using surface electromyogram (sEMG) measurements. The results demonstrated that the proposed low-cost single-PAM-actuated robotic orthosis could be a solution to robotic rehabilitation demands, especially in low-middle-income countries (LMIC).

IntroductionStroke-related deficits often include motor impairments and gait dysfunction, leading to a limitation of social activities and consequently affecting the quality of life of stroke survivors. Neurorehabilitation takes advantage of the contribution of different techniques in order to achieve more benefits for patients. Robotic devices help to improve the outcomes of physical rehabilitation. Moreover, motor imagery seems to play a role in neurological rehabilitation since it leads to the activation of the same brain areas as actual movements. This study investigates the use of a combined physical and cognitive protocol for gait rehabilitation in stroke patients.MethodsSpecifically, we tested the efficacy of a 5-week training program using a robotic orthosis (P.I.G.R.O.) in conjunction with motor imagery training. Twelve chronic stroke patients participated in the study. We evaluated balance and gait performance before and after the training. Six of them underwent fMRI examination before and after the training to assess the effects of the protocol on brain plasticity mechanisms in motor and imagery tasks.ResultsOur results show that the rehabilitation protocol can effectively improve gait performance and balance and reduce the risk of falls in stroke patients. Furthermore, the fMRI results suggest that rehabilitation is associated with cerebral plastic changes in motor networks.DiscussionThe present findings, if confirmed by future research, have the potential to advance the development of new, more effective rehabilitation approaches for stroke patients, improving their quality of life and reducing the burden of stroke-related disability.

BackgroundThe Lokomat® is a device utilized for gait training in post-stroke patients. Through a systematic review, the objective was to determine whether robot-assisted gait training with the Lokomat® is more effective in enhancing lower extremity rehabilitation in patients with stroke in comparison to conventional physical therapy (CPT).MethodsIn this study, a systematic search was conducted in various databases, including CINAHL, MEDLINE, PubMed, Embase, Cochrane Library, Scopus, Web of Science, and Physiotherapy Evidence Database (PEDro), as well as bibliographies of previous meta-analyses, to identify all randomized controlled trials that investigated the use of Lokomat® devices in adult stroke patients. The study aimed to derive pooled estimates of standardized mean differences for six outcomes, namely, Fugl–Meyer Assessment lower-extremity subscale (FMA-LE), Berg Balance Scale (BBS), gait speed, functional ambulation category scale (FAC), timed up and go (TUG), and functional independence measure (FIM), through random effects meta-analyses.ResultsThe review analyzed 21 studies with a total of 709 participants and found that the use of Lokomat® in stroke patients resulted in favorable outcomes for the recovery of balance as measured by the BBS (mean difference = 2.71, 95% CI 1.39 to 4.03; p < 0.0001). However, the FAC showed that Lokomat® was less effective than the CPT group (mean difference = −0.28, 95% CI −0.45 to 0.11, P = 0.001). There were no significant differences in FMA-LE (mean difference = 1.27, 95% CI −0.88 to 3.42, P = 0.25), gait speed (mean difference = 0.02, 95% CI −0.03 to 0.07, P = 0.44), TUG (mean difference = −0.12, 95% CI −0.71 to 0.46, P = 0.68), or FIM (mean difference = 2.12, 95% CI −2.92 to 7.16, P = 0.41) between the Lokomat® and CPT groups for stroke patients.ConclusionOur results indicate that, with the exception of more notable improvements in balance, robot-assisted gait training utilizing the Lokomat® was not superior to CPT based on the current literature. Considering its ability to reduce therapists' work intensity and burden, the way in which Lokomat® is applied should be strengthened, or future randomized controlled trial studies should use more sensitive assessment criteria.

Introduction: Poliomyelitis has been considered a statutory notifiable infectious disease in Hong Kong since 1948. Approximately 15% to 80% of patients suffer from post-polio syndrome (PPS) with an increased risk of falling and chronic pain. Most of them relied on the use of knee lock-type orthoses as aids. This study aimed to evaluate the effect of using a custom-fit knee robotic orthosis on their gait performance. Materials and Methods: A case series report was used for this study on a group of individuals suffering from chronic PPS who used orthoses and had a history of falling. A knee robotic orthosis was custom-fit for eight sessions of walking practice. Assessments included laboratory gait analysis, functional measures, and subjective ratings of exertional level. Pain responses were recorded to evaluate the effect of using the knee robotic orthosis on participants' gait performance. Results: Five participants completed the study in using the knee robotic orthosis. All achieved reduction in shoulder tilting and trunk swaying movement on walking at the anterior-posterior and the medial-lateral direction. A total of 80% of the study participants achieved reduction in trunk rotation movement, lower-limb circumduction, and hip hiking movement on the affected side on walking. All study participants were able to demonstrate improvement in their gait symmetry after using the knee robotic orthosis as reflected by the symmetric index improvement of kinematics. The rate of perceived exertion and the visual analog scale of pain in all study participants were reported lower when they used the knee robotic orthosis. However, the 10-m walking time achieved was longer. Conclusions: The knee robotic orthosis had a positive effect on remediating the abnormal kinematics of PPS patients using conventional lock-knee orthosis after eight sessions of training practice. Reduction in the limping gait pattern and improvement in gait symmetry was achieved in using a knee robotic orthosis for walking. The chronic pain response and the physical exertional level on walking were also reduced. However, the walking speed achieved was slower. Clinical Relevance: The application of the knee robotic orthosis for walking assist is new to most of the PPS patients. The positive outcomes achieved merit further research for future clinical practice. [ABSTRACT FROM AUTHOR]

This study proposed an open-source myoelectric robotic hand orthosis prototype to support people with neuromuscular disorders in performing activities of daily living (ADLs). A user-tuned methodology was applied, designing the system's usability and ergonomics with recommendations in literature (2017 to 2020), thus calibrating the prototype by user's metrics. It has two modules: transmitter–interpreter system (TIS) and receiver–actuator system (RAS) that performs three hand pose: (i) pulp pinch, (ii) cylindrical grip, and (iii) resting hand. The system uses a linear discriminant analysis (LDA) classifier with real-time disruptive windowing (80 ms) and a majority vote algorithm (n=3) as post-processing. TIS classifies and transmits a hand pose within 300 ms to RAS, which executes the hand pose. The LDA classifier was trained with ten datasets of surface myoelectric signals (sMES) recorded from a healthy volunteer. The system's accuracy reached 90% in real-time tests with three everyday objects. Splints were 3D-printed with resistant material, so the fitting and range of motion were comfortable for the volunteer. The prototype achieved the recommendations in the literature, and it was the orthosis that most fulfilled said requirements compared to state-of-the-art (2017 to 2020) myoelectric robotic hand orthosis. However, it only assists with finger flexion. The open-source format provides other researchers a starting point to develop an orthosis for in-home rehabilitation that actively assists in ADLs. Additionally, production costs for the orthosis are R$856.35, or 2.98% of the cheapest myoelectric hand orthosis available on the market (PowerGrip), both quoted on November 2021. [Display omitted] • Myoelectric robotic hand orthosis developed following an user-tuned methodology. • Ergonomics and system usability are custom made from the user's metrics. • Open-source project with low manufacturing cost compared to commercial models. • Prototype can execute pulp pinch, cylindrical grip and a resting hand state. • Tested using three daily objects with different shapes and weights. [ABSTRACT FROM AUTHOR]

Rehabilitation robots are designed to help patients improve their recovery from injury by supporting them to perform repetitive and systematic training sessions. These robots are not only able to guide the subjects’ lower-limb to a designate trajectory, but also estimate their disability and adapt the compliance accordingly. In this research, a new control strategy for a high compliant lower-limb rehabilitation orthosis system named AIRGAIT is developed. The AIRGAIT orthosis is powered by pneumatic artificial muscle actuators. The trajectory tracking controller based on a modified computed torque control which employs a fractional derivative is proposed for the tracking purpose. In addition, a new method is proposed for compliance control of the robotic orthosis which results in the successful implementation of the assist-as-needed training strategy. Finally, various subject-based experiments are carried out to verify the effectiveness of the developed control system.

Introduction: Stroke-related deficits often include motor impairments and gait dysfunction, leading to a limitation of social activities and consequently affecting the quality of life of stroke survivors. Neurorehabilitation takes advantage of the contribution of different techniques in order to achieve more benefits for patients. Robotic devices help to improve the outcomes of physical rehabilitation. Moreover, motor imagery seems to play a role in neurological rehabilitation since it leads to the activation of the same brain areas as actual movements. This study investigates the use of a combined physical and cognitive protocol for gait rehabilitation in stroke patients. Methods: Specifically, we tested the efficacy of a 5-week training program using a robotic orthosis (P.I.G.R.O.) in conjunction with motor imagery training. Twelve chronic stroke patients participated in the study. We evaluated balance and gait performance before and after the training. Six of them underwent fMRI examination before and after the training to assess the effects of the protocol on brain plasticity mechanisms in motor and imagery tasks. Results: Our results show that the rehabilitation protocol can effectively improve gait performance and balance and reduce the risk of falls in stroke patients. Furthermore, the fMRI results suggest that rehabilitation is associated with cerebral plastic changes in motor networks. Discussion: The present findings, if confirmed by future research, have the potential to advance the development of new, more effective rehabilitation approaches for stroke patients, improving their quality of life and reducing the burden of stroke-related disability. [ABSTRACT FROM AUTHOR]

Stroke has a considerable incidence in the world population and would cause sequelae in the upper limbs. One way to increase the efficiency in the rehabilitation process of patients with these sequelae is through robot-assisted therapy. The present study developed a portable robotic orthosis called Pinotti Portable Robotic Exoskeleton (PPRE) and validated its functioning in clinical tests. The static and dynamic parts of the device modules are described. Design issues, such as heavyweight and engine positioning, have been optimized. The implementation of control was through a smartphone application that communicates with a microcontroller to perform desired movements. Four individuals with motor impairment of the upper limbs due to stroke performed clinical tests to validate the device. Participants did not mention pain, discomfort, tingling, and paresthesia. The robotic device showed the ability to perform the flexion and extension movements of the fingers and elbow. The PPRE was confirmed to be adequate and functional at different levels of motor impairment assessed. The orthosis presented advantages over the currently existing devices, concerning its biomechanical functioning, portability, comfort, and versatility. Thus, the apparatus has the great innovative potential to become a device for home use, serving as an aid to the therapist and facilitating the rehabilitation of patients after an injury. In a larger sample, future studies are needed to assess the effect of a robotic orthosis on the level of rehabilitation in individuals with upper limb impairment. [ABSTRACT FROM AUTHOR]

A safe interaction is crucial in wearable robotics in general, while in assistive and rehabilitation applications, robots may also be required to minimally perturb physiological movements, ideally acting as perfectly transparent machines. The actuation system plays a central role because the expected performance, in terms of torque, speed and control bandwidth, must not be achieved at the expense of lightness and compactness. Actuators embedding compliant elements, such as series elastic actuators, can be designed to meet the above-mentioned requirements in terms of high energy storing capacity and stability of torque control. A number of series elastic actuators have been proposed over the past 20 years in order to accommodate the needs arising from specific applications. This paper presents a novel series elastic actuator intended for the actuation system of a lower limb wearable robot, recently developed in our lab. The actuator is able to deliver 300 W and has a novel architecture making its centre of mass not co-located with its axis of rotation, for an easier integration into the robotic structure. A custom-made torsion spring with a stiffness of 272.25 N·m·rad– 1 is directly connected to the load. The delivered torque is calculated from the measurement of the spring deflection, through two absolute encoders. Testing on torque measurement accuracy and torque/stiffness control are reported.

This paper presents newly developed algorithms for automatic adaptation of motion for a robotic rehabilitation device. The algorithms adapt the gait pattern of patients that walk on a treadmill. Three different algorithms were developed. The first one is based on inverse dynamics and online minimization of the human-machine interaction torque. The second one is based on direct dynamics and estimation of the desired variation in the gait-pattern acceleration. The third algorithm is based on impedance control and direct adaptation of the gait pattern angular trajectories. The algorithms were tested and compared in computer simulations and actual experiments on healthy subjects and patients. In simulations, all algorithms have adapted the gait pattern toward the desired one, which led to a greater than 40% reduction of interaction torques. The impedance-control-based algorithm performed best in the experiments. Index Terms--Adaptive control, rehabilitation of locomotion, reference joint-angle trajectory adaptation, treadmill training.

Rehabilitation robots may help the patient improve their recovery by supporting them to perform repetitive, systematic training sessions. Safety and comfortable feeling of the patients who training with robots is an important issue in not only the steady state but also the transient process. In this research, the trajectory tracking control problems of a two-degrees of freedom (2-DOF) robotic orthosis is discussed. The robotic orthosis is powered by pneumatic artificial muscles (PAMs) in an antagonistic configuration. based on a mathematical model, a modified computed torque control scheme is employed to enhance the tracking performance. The effectiveness of the proposed control strategy is verified by the experiments with the participation of different subjects.

The design of a new robotic orthosis to fully assist various overhead operations in the shipbuilding industry is proposed, and a dynamics simulation and an experimental study are conducted to validate the performance of impedance control of the new orthosis. There are considerable payloads from cables and reaction forces from injection parts during the blasting cleaning and painting in the shipbuilding process, and these can lead to work-related musculoskeletal disorders in the shoulder and elbow joints. Thus, in this research, the entire robotic orthosis designed for the dynamics simulation consists of joints with a total of 6 degrees of freedom (DOF): a 2-DOF shoulder, a 1-DOF elbow, and a 3-DOF wrist. The equations of motion of the designed robotic orthosis have been obtained on the basis of a relative-coordinate formulation. The contact force between the robotic orthosis and the human hand, gravitational force, and the control forces were considered as external forces. The results of the dynamics simulation are significant and show that the transient motions of robotic orthosis can be well controlled by using an impedance control scheme, while the compliance control is able to control only the steady-state motions. The control of transient motions is important because any unexpected impact forces or undesired dynamic behaviours in human–robot interactions may negatively affect both the worker's physical conditions and the quality of the work. Thus, in this research, we validate the suitability of the impedance control scheme in the described applications. Moreover, for simplicity of the experimental study and for considering the minimally required DOF in painting and blasting, only 3-DOF motions were considered in the dynamics simulation in this research. Finally, the obtained experimental results fully support the idea that the impedance control scheme is appropriate to control the robotic orthosis for overhead operations requiring a high degree of accuracy. [ABSTRACT FROM PUBLISHER]

This paper introduces a wearable robotic orthosis with spring-assist actuators, which is designed to assist people who have difficulty in walking. The spring-assist actuator consists of an electrical motor and a spring, which are attached to a rotational axis in parallel to each other. The spring-assist actuator is developed based on the analysis on the stiffness of the knee and hip joints during walking. "COWALK-Mobile," which is a wearable robotic orthosis, is developed using the spring-assist actuators to reduce the required motor torque during walking. The COWALK-Mobile has active hip and knee joints and passive ankle joints to provide assistive torque to the wearer. The required joint torque is generated by the spring as well as the electrical motor, which results in a decrease of maximum required torque for the motor. In order to evaluate the performance of the spring-assist actuator, experiments are carried out. The experiments show that the spring-assist actuators reduced the required motor torque during walking.

Rehabilitation under water is a viable physical rehabilitation option, but it has some limitations in terms of adapting to needs of each patient. In addition, its facility requirements are relatively high. Simulating the fluid environment using a robotic system would enable therapists adjust various parameters so that the therapy is tailored to the patient's unique state. Also, using a robotic system instead might be less costly and easily reachable. In this study, human lower extremity movement in fluids is modeled. This model is verified by comparing computer simulations with the results of previous experimental studies. Then, the model is used to create a control scheme which is implemented on a robotic gait trainer. Output torques are measured to check the effectiveness of the controller in simulating the fluid environment while compensating for weight and friction of the robotic system. Measurements showed that the desired joint torques were achieved and the controller was able to make the orthosis transparent to the patient. A hip extension exercise used in aquatic therapy was performed with the robotic system while varying drag coefficient, fluid density and flow velocity, and the data collected is presented.

Rehabilitation robots are designed to help patients improve their recovery from injury by supporting them to perform repetitive and systematic training sessions. These robots are not only able to guide the subjects’ lower-limb to a designate trajectory, but also estimate their disability and adapt the compliance accordingly. In this research, a new control strategy for a high compliant lower-limb rehabilitation orthosis system named AIRGAIT is developed. The AIRGAIT orthosis is powered by pneumatic artificial muscle actuators. The trajectory tracking controller based on a modified computed torque control which employs a fractional derivative is proposed for the tracking purpose. In addition, a new method is proposed for compliance control of the robotic orthosis which results in the successful implementation of the assist-as-needed training strategy. Finally, various subject-based experiments are carried out to verify the effectiveness of the developed control system. [ABSTRACT FROM AUTHOR]

Neuroplasticity allows the human nervous system to adapt and relearn motor control following stroke. Rehabilitation therapy, which enhances neuroplasticity, can be made more effective if assisted by robotic tools. In this paper, a novel 4-SPS parallel robot has been developed to provide recovery of wrist movements post-stroke. The novel mechanism presented here was inspired by the forearm anatomy and can provide the rotational degrees of freedom required for all wrist movements. The robot design has been discussed in detail along with the necessary constructional, kinematic, and static analyses. The spatial workspace of the robot is estimated considering various dimensional and application-specific constraints besides checking for singular configurations. The wrist robot has been further evaluated using important performance indices such as condition number, actuator forces, and stiffness. The pneumatic artificial muscles exhibit varying stiffness, and therefore, workspace points are reached with different overall stiffness of the robot. It is essential to assess robot workspace points that can be reached with positive forces in actuators while maintaining a positive definite overall stiffness matrix. After the above analysis, design optimization has been carried out using an evolutionary algorithm whereby three critical criteria are optimized simultaneously for optimal wrist robot design. [ABSTRACT FROM AUTHOR]

Mobility options for persons suffering from paraplegia or paraparesis are limited to mainly wheeled devices. There are significant health, psychological, and social consequences related to being confined to a wheelchair. We present the Mina, a robotic orthosis for assisting mobility, which offers a legged mobility option for these persons. Mina is an overground robotic device that is worn on the back and around the legs to provide mobility assistance for people suffering from paraplegia or paraparesis. Mina uses compliant actuation to power the hip and knee joints. For paralyzed users, balance is provided with the assistance of forearm crutches. This paper presents the evaluation of Mina with two paraplegics (SCI ASIA-A). We confirmed that with a few hours of training and practice, Mina is currently able to provide paraplegics walking mobility at speeds of up to 0.20 m/s. We further confirmed that using Mina is not physically taxing and requires little cognitive effort, allowing the user to converse and maintain eye contact while walking., (© 2011 IEEE)

Lower limb rehabilitation robots based on linkage-based mechanisms have recently drawn significant attention in the field due to their numerous advantages. The control of previously proposed linkage-based gait rehabilitation robotic orthoses has been achieved using constant speed control without consideration for the interaction forces. However, such an approach can be harmful to people with stroke since the level of disability varies among individuals, and it may cause potential injuries when excessive force is applied by the robot. To overcome this limitation and improve the rehabilitation process, it is necessary to recognize the force exerted by the person during walking and adjust the robot's assistive torque accordingly, to provide synchronized motion. Thus, in this work, a human-cooperative approach based on a stiffness control strategy for the six-bar linkage-based gait rehabilitation robot is presented. The proposed methodology can serve as a solid foundation for developing a human-cooperative approach for linkage-based lower limb rehabilitation robotic orthoses. The control was validated and tested with eight healthy human subjects. As a result, customized robotic assistance with this mechanism can be provided during training to meet the individual needs of stroke patients, which can lead to increased engagement and contribution, thus improving treatment outcomes. [ABSTRACT FROM AUTHOR]

Body-weight supported treadmill training following neurological disorders such as stroke and spinal cord injuries (SCI) has become an integral part of rehabilitation for treating gait disorders. Unfortunately techniques for selecting important training parameters, such as walking speed and body-weight support, have not been established. Here we present a 3-D inverse-dynamics based approach for evaluating an individual's ability to ambulate, in terms of evaluating the magnitude and timing of joint moments at the ankle, knee and hip. This technique, which utilizes an instrumented gait robot, allows clinicians and researchers the ability to determine the training parameters in which subjects generate joint moments at the proper phases of the gait cycle which when combined with electromyographic recordings, can help establish and then progress training parameters for individuals on a subject-by-subject basis. We believe that training subjects at their preferred walking speed and body-weight support will lead to higher functional outcomes.

The use of robotic gait training systems has become commonplace world-wide. In particular, the Lokomat robotic orthosis (Hocoma AG, Volketswil, Switzerland) is in use at nearly 75 facilities treating patients with spinal cord injury, stroke, and other neurological impairments. Despite the extensive use of the device, no studies have reported the leg kinematic trajectories while walking in the device. Furthermore, because the subject's legs are not rigidly coupled to the device, there is the potential for significant leg movement inside the device which also has not been reported. Here we report differences in kinematic trajectories between walking in the Lokomat and walking on a treadmill, as well as the relative limb motion within the Lokomat for a single representative subject. Using high-speed motion analysis, it was found that while similar knee and hip angle patterns were produced when walking on the treadmill and while walking in the Lokomat, there were significant differences (p<.0.01) in percent time spent in swing phase, maximum hip and knee flexion, and maximum hip extension. There was also a larger amount of misalignment at the hip (18.2 mm) than at the knees (12 mm) when the joint positions in space were compared.

Neurological diseases - such as spinal cord injury, stroke and traumatic brain injury - frequently result in gait impairment The recovery of the walking ability requires functional training (i.e. walking), as previous research in man and animal has shown. Because the patient usually has reduced voluntary muscle force early after the incident, his/her movements require external support by physical therapists or special robotic devices. The Lokomat is a robotic gait orthosis with electromechanical drives that supports walking on a treadmill with body weight support. Because the movements are performed according to a predefined trajectory, there is no visible cue to the amount the patient is contributing. However, the forces measured within the drives can deliver an estimation of this contribution. Based on these measurements, biofeedback on the patient's gait performance was added as a new feature. The visual display will allow the patient to get direct feedback on his/her efforts, and will allow the therapist to instruct the patient better. We report here that the biofeedback can correctly reflect the activity of a healthy subject, that patients can benefit from the use, and what the patients' opinion is.

Powered lower limb orthoses have been commercially available for patients with Spinal Cord Injuries (SCI) or stroke. However, studies have shown that there are adverse effects on kinematics as well as metabolic energy of the users due to the additional mass of the orthoses to the lower limbs. Since additional metabolic energy required to use the powered orthoses is one of the reasons to avoid using them, it is important to reduce the mass and moment of inertia of the exoskeletons for longer use and better outcomes. In this study, a powered-lower-limb orthosis for stroke patients using a cable-differential mechanism, which is called COWALK-Mobile 2, was proposed. The cable-differential mechanism was utilized to transmit the actuating torques from actuators to the hip and knee joints. The cable-differential mechanism enabled the actuators to be located near the hip, which yields reduced inertia of the device, as well as the loads at the joints to be shared by the actuators, which results in smaller required actuator torque. Optimal radii of the pulleys for the cable-differential mechanism were found for efficient load-sharing during walking. Experimental results with a healthy person walking on a level surface have shown that larger joint torques were generated with smaller actuator torques.

Abstract--Recent studies have confirmed that regular treadmill training can improve walking capabilities in incomplete spinal cord-injured subjects. At the beginning of this training the leg movements of the patients have to be assisted by physiotherapists during gait on the moving treadmill. The physical capabilities and the individual experience of the therapists usually limit this training. A driven gait orthosis (DGO) has been developed that can move the legs of a patient in a physiological way on the moving treadmill. The orthosis is adjustable in size so different patients can use it. Actuators at the knee and hip joints are controlled by a position controller. With the DGO the legs of patients with different degrees of paresis and spasticity could be trained for more than half an hour, and physiological gait patterns were obtained. [ABSTRACT FROM AUTHOR]

Rehabilitation and mobility assistance using robotic orthosis or exoskeletons have shown potential in aiding those with musculoskeletal disorders. Artificial muscles are the main component used to drive robotics and bio-assistive devices. However, current fabrication methods to produce artificial muscles are technically challenging and laborious for medical staff at clinics and hospitals. This study aims to investigate a printhead system for material extrusion of helical polymer artificial muscles. In the proposed system, an internal fluted mandrel within the printhead and a temperature control module were used simultaneously to solidify and stereotype polymer filaments prior to extrusion from the printhead with a helical shape. Numerical simulation was applied to determine the optimal printhead design, as well as analyze the coupling effects and sensitivity of the printhead geometries on artificial muscle fabrication. Based on the simulation analysis, the printhead system was designed, fabricated, and operated to extrude helical filaments using polylactic acid. The diameter, thickness, and pitch of the extruded filaments were compared to the corresponding geometries of the mandrel to validate the fabrication accuracy. Finally, a printed filament was programmed and actuated to test its functionality as a helical artificial muscle. The proposed printhead system not only allows for the stationary extrusion of helical artificial muscles but is also compatible with commercial 3D printers to freeform print helical artificial muscle groups in the future.

Gait modes, such as level walking, stair ascent/descent, and ramp ascent/descent, show different lower-limb kinematic and kinetic characteristics. Therefore, an accurate detection of these modes is critical for a wearable robot to provide appropriate power assistance. In this paper, a fast gait-mode-detection method based on a body sensor system is proposed. A fuzzy logic algorithm is used to estimate the likelihoods of gait modes in real time. Since the proposed fast gait mode detection makes it possible to select appropriate kinematic and kinetic models for each gait mode, assistive torques required for assisting the human motions can be obtained more naturally and immediately. The proposed methods are all verified by experiments with a lower-limb exoskeletal assistive robot with transparent actuation by series elastic actuators, called the exoskeletal robotic orthosis for walking assistance. Four healthy subjects participated in the experiments. All subjects were asked to perform different gait modes using their normal and simulated abnormal gaits, i.e., blocking the knee joint of one leg during walking. Latency and success rate of gait mode detection are selected as performance criteria. The effectiveness of the proposed gait-mode-based assistive strategy is evaluated using electromyography muscular activities. [ABSTRACT FROM AUTHOR]

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Disabilities are a global issue due to the decrease in life quality and mobility of patients, especially people suffering from hand disabilities. This paper presents a review of active hand exoskeleton technologies, over the past decade, for rehabilitation, assistance, augmentation, and haptic devices. Hand exoskeletons are still an active research field due to challenges that engineers face and are trying to solve. Each hand exoskeleton has certain requirements to fulfil to achieve their aims. These requirements have been extracted and categorized into two sections: general and specific, to give a common platform for developing future devices. Since this is still a developing area, the requirements are also shaped according to the advances in the field. Technical challenges, such as size requirements, weight, ergonomics, rehabilitation, actuators, and sensors are all due to the complex anatomy and biomechanics of the hand. The hand is one of the most complex structures in the human body; therefore, to understand certain design approaches, the anatomy and biomechanics of the hand are addressed in this paper. The control of these devices is also an arising challenge due to the implementation of intelligent systems and new rehabilitation techniques. This includes intention detection techniques (electroencephalography (EEG), electromyography (EMG), admittance) and estimating applied assistance. Therefore, this paper summarizes the technology in a systematic approach and reviews the state of the art of active hand exoskeletons with a focus on rehabilitation and assistive devices.

We previously proposeda power assist robot and conductedexperiments for cervical cord injury(CCI) patients. This paper proposed a new type of robot orthosis by making of their residual function around their shoulder in order to operate the wheelchair. A lock/unlock mechanism on the elbow joint is effectively used to transmit the residual function around the shoulder to the hand. We confirmedthat three patients with CCI could use their residual functionaround their shoulderand operate a wheelchair effectively in outdoor environment like high resistance roads and roads with a slope by measuring velocity of the wheelchair and electromyography of his shoulder muscle.

This paper presents newly developed algorithms for automatic adaptation of motion for a robotic rehabilitation device. The algorithms adapt the gait pattern of patients that walk on a treadmill. Three different algorithms were developed. The first one is based on inverse dynamics and online minimization of the human-machine interaction torque. The second one is based on direct dynamics and estimation of the desired variation in the gait-pattern acceleration. The third algorithm is based on impedance control and direct adaptation of the gait pattern angular trajectories. The algorithms were tested and compared in computer simulations and actual experiments on healthy subjects and patients. In simulations, all algorithms have adapted the gait pattern toward the desired one, which led to a greater than 40% reduction of interaction torques. The impedance-control-based algorithm performed best in the experiments. [ABSTRACT FROM AUTHOR]

Background and Objectives: While body weight support (BWS) intonation is vital during conventional gait training of neurologically challenged subjects, it is important to evaluate its effect during robot assisted gait training. In the present research we have studied the effect of BWS intonation on muscle activities during robotic gait training using dynamic simulations. Methods: Two dimensional (2-D) musculoskeletal model of human gait was developed conjointly with another 2-D model of a robotic orthosis capable of actuating hip, knee and ankle joints simultaneously. The musculoskeletal model consists of eight major muscle groups namely; soleus (SOL), gastrocnemius (GAS), tibialis anterior (TA), hamstrings (HAM), vasti (VAS), gluteus maximus (GLU), uniarticular hip flexors (iliopsoas, IP), and Rectus Femoris (RF). BWS was provided at levels of 0, 20, 40 and 60% during the simulations. In order to obtain a feasible set of muscle activities during subsequent gait cycles, an inverse dynamics algorithm along with a quadratic minimization algorithm was implemented. Results: The dynamic parameters of the robot assisted human gait such as joint angle trajectories, ground contact force (GCF), human limb joint torques and robot induced torques at different levels of BWS were derived. The patterns of muscle activities at variable BWS were derived and analysed. For most part of the gait cycle (GC) the muscle activation patterns are quite similar for all levels of BWS as is apparent from the mean of muscle activities for the complete GC. Conclusions: Effect of BWS variation during robot assisted gait on muscle activities was studied by developing dynamic simulation. It is expected that the proposed dynamic simulation approach will provide important inferences and information about the muscle function variations consequent upon a change in BWS during robot assisted gait. This information shall be quite important while investigating the influence of BWS intonation on neuromuscular parameters of interest during robotic gait training. [ABSTRACT FROM AUTHOR]

It is a common hypothesis in the field of robot-assisted gait rehabilitation that the active involvement and voluntary participation of neurologically impaired subjects in the robotic gait training process may enhance the outcomes of such therapy. An adaptive seamless assist-as-needed (AAN) control scheme was developed for the robotic gait training. The AAN control scheme learns in real time the disability level of human subjects based on the trajectory tracking errors and adapts the robotic assistance accordingly. The overall AAN control architecture works on the basis of a robust adaptive control approach. The performance of seamless AAN control scheme was evaluated during treadmill training with a compliant robotic orthosis having six degrees of freedom. Two experiments, namely, trajectory following experiment and the AAN experiment were carried out to evaluate the performance of seamless adaptive AAN control scheme. It was found that the robotic orthosis is capable of guiding the subjects’ limbs on reference trajectories during the trajectory following experiment. Also, a variation in robotic assistance was recorded during the AAN experiment based on the voluntary participation of human subjects. This work is an advance on the current state of the art in the compliant actuation of robotic gait rehabilitation orthoses in the context of seamless AAN gait training. [ABSTRACT FROM AUTHOR]