Showing papers on "Exoskeleton Device published in 2020"

Improving the energy economy of human running with powered and unpowered ankle exoskeleton assistance

Abstract: Exoskeletons that reduce energetic cost could make recreational running more enjoyable and improve running performance. Although there are many ways to assist runners, the best approaches remain unclear. In our study, we used a tethered ankle exoskeleton emulator to optimize both powered and spring-like exoskeleton characteristics while participants ran on a treadmill. We expected powered conditions to provide large improvements in energy economy and for spring-like patterns to provide smaller benefits achievable with simpler devices. We used human-in-the-loop optimization to attempt to identify the best exoskeleton characteristics for each device type and individual user, allowing for a well-controlled comparison. We found that optimized powered assistance improved energy economy by 24.7 ± 6.9% compared with zero torque and 14.6 ± 7.7% compared with running in normal shoes. Optimized powered torque patterns for individuals varied substantially, but all resulted in relatively high mechanical work input (0.36 ± 0.09 joule kilogram-1 per step) and late timing of peak torque (75.7 ± 5.0% stance). Unexpectedly, spring-like assistance was ineffective, improving energy economy by only 2.1 ± 2.4% compared with zero torque and increasing metabolic rate by 11.1 ± 2.8% compared with control shoes. The energy savings we observed imply that running velocity could be increased by as much as 10% with no added effort for the user and could influence the design of future products.

Industrial exoskeletons: Need for intervention effectiveness research

Abstract: Exoskeleton devices are being introduced across several industry sectors to augment, amplify, or reinforce the performance of a worker's existing body components-primarily the lower back and the upper extremity. Industrial exoskeletons may play a role in reducing work-related musculoskeletal disorders arising from lifting and handling heavy materials or from supporting heavy tools in overhead work. However, wearing an exoskeleton may pose a number of risks that are currently not well-studied. There are only a few studies about the safety and health implications of wearable exoskeletons and most of those studies involve only a small number of participants. Before the widespread implementation of industrial exoskeletons occurs, there is need for prospective interventional studies to evaluate the safety and health effectiveness of exoskeletons across various industry sectors. Developing a research strategy to fill current safety and health knowledge gaps, understanding the benefits, risks, and barriers to adoption of industrial exoskeletons, determining whether exoskeleton can be considered a type of personal protective equipment, and advancing consensus standards that address exoskeleton safety, should be major interests of both the occupational safety and health research and practice communities.

Gait Adaptation Using a Cable-Driven Active Leg Exoskeleton (C-ALEX) With Post-Stroke Participants

Abstract: Individuals with chronic hemiparesis post-stroke exhibit gait impairments that require functional rehabilitation through training. Exoskeletal robotic assistive devices can provide a user with continuous assistance but impose movement restrictions. There are currently devices that allow unrestricted movement but provide assistance only intermittently at specific points of the gait cycle. Our design, a cable-driven active leg exoskeleton (C-ALEX), allows the user both unrestricted movement and continuous force assistance throughout the gait cycle to assist the user in new walking patterns. In this study, we assessed the ability of C-ALEX to induce a change in the walking patterns of ten post-stroke participants using a single-session training protocol. The ability of C-ALEX to accurately provide forces and torques in the desired directions was also evaluated to compare its design performance to traditional rigid-link designs. Participants were able to reach 91% ± 12% of their target step length and 89% ± 13% of their target step height. The achieved step parameters differed significantly from participant baselines ( ${p} ). To quantify the performance, the forces in each cable’s out of the plane movements were evaluated relative to the in-plane desired cable tension magnitudes. This corresponded to an error of under 2Nm in the desired controlled joint torques. This error magnitude is low compared to the system command torques and typical adult biological torques during walking (2–4%). These results point to the utility of using non-restrictive cable-driven architectures in gait retraining, in which future focus can be on rehabilitating gait pathologies seen in stroke survivors.

How to run 50% faster without external energy

Abstract: Technological innovations may enable next-generation running shoes to provide unprecedented mobility. But how could a running shoe increase the speed of motion without providing external energy? We found that the top speed of running may be increased more than 50% using a catapult-like exoskeleton device, which does not provide external energy. Our finding uncovers the hidden potential of human performance augmentation via unpowered robotic exoskeletons. Our result may lead to a new-generation of augmentation devices developed for sports, rescue operations, and law enforcement, where humans could benefit from increased speed of motion.

Decoupling Finger Joint Motion in an Exoskeletal Hand: A Design for Robot-Assisted Rehabilitation

Abstract: In this paper, a cable-driven exoskeleton device is developed for stroke patients to enable them to perform passive range of motion exercises and teleoperation rehabilitation of their impaired hands. Each exoskeleton finger is controlled by an actuator via two cables. The motions between the metacarpophalangeal and distal/proximal interphalangeal joints are decoupled, through which the movement pattern is analogous to that observed in the human hand. A dynamic model based on the Lagrange method is derived to estimate how cable tension varies with the angular position of the finger joints. Two discernable phases are observed, each of which reflects the motion of the metacarpophalangeal and distal/proximal interphalangeal joints. The tension profiles of exoskeleton fingers predicted by the Lagrange model are verified through a mechatronic integrated platform. The model can precisely estimate the tensions at different movement velocities, and it shows that the characteristics of two independent phases remain the same even for a variety of movement velocities. The feasibility for measuring resistance when manipulating a patient's finger is demonstrated in human experiments. Specifically, the net force required to move a subject's finger joints can be accounted for by the Lagrange model.

Disturbance Observer-Based Patient-Cooperative Control of a Lower Extremity Rehabilitation Exoskeleton

Abstract: Many patients with stroke are suffering lower limb locomotor dysfunctions all over the world. Body weight supported treadmill training has proven to be an effective post-stroke rehabilitation training method for these people’s recovery. Nowadays, lower extremity rehabilitation exoskeleton composed of a pair of mechanical legs has been introduced into body weight supported treadmill training, which can guide and assist the movements of the patient’s legs. However, active movements of the patient are hardly to be achieved when the rehabilitation exoskeleton is controlled by a commonly utilized position-based passive strategy. Considering the restriction above, a weight supported rehabilitation training exoskeleton device was designed in this paper to ensure the stroke patient can participate in rehabilitation training voluntarily. To realize this goal, a patient-cooperative rehabilitation training strategy based on adaptive impedance control is adopted for the swing phase in the training. Human–exoskeleton interaction torques are evaluated by a backpropagation neural network and a disturbance observer whose stability is proved by Lyapunov’s law. With no additional demand of interaction torque sensors, the complexity of this system is simplified and the cost is reduced. In order to promote the involvement of patient during the rehabilitation training, fuzzy algorithm is used to adjust the impedance parameters according to the human–exoskeleton interaction torques. The effectiveness of the whole rehabilitation control strategy is demonstrated by experimental results.

HandMATE: Wearable Robotic Hand Exoskeleton and Integrated Android App for At Home Stroke Rehabilitation

Abstract: We have developed HandMATE (Hand Movement Assisting Therapy Exoskeleton); a wearable motorized hand exoskeleton for home-based movement therapy following stroke. Each finger and the thumb is powered by a linear actuator which provides flexion and extension assistance. Force sensitive resistors integrated into the design measure grasp and extension initiation force. An assistive therapy mode is based on an admittance control strategy. We evaluated our control system via subject and bench testing. Errors during a grip force tracking task while using the HandMATE were minimal (<1%) and comparable to unassisted healthy hand performance. We also outline a dedicated app we have developed for optimal use of HandMATE at home. The exoskeleton communicates wirelessly with an Android tablet which features guided exercises, therapeutic games and performance feedback. We surveyed 5 chronic stroke patients who used the HandMATE device to further evaluate our system, receiving positive feedback on the exoskeleton and integrated app.

Adapting to the Mechanical Properties and Active Force of an Exoskeleton by Altering Muscle Synergies in Chronic Stroke Survivors

Abstract: Chronic stroke survivors often suffer from gait impairment resistant to intervention. Recent rehabilitation strategies based on gait training with powered exoskeletons appear promising, but whether chronic survivors may benefit from them remains controversial. We evaluated the potential of exoskeletal gait training in restoring normal motor outputs in chronic survivors (N = 10) by recording electromyographic signals (EMGs, 28 muscles both legs) as they adapted to exoskeletal perturbations, and examined whether any EMG alterations after adaptation were underpinned by closer-to-normal muscle synergies. A unilateral ankle-foot orthosis that produced dorsiflexor torque on the paretic leg during swing was tested. Over a single session, subjects walked overground without exoskeleton (FREE), then with the unpowered exoskeleton (OFF), and finally with the powered exoskeleton (ON). Muscle synergies were identified from EMGs using non-negative matrix factorization. During adaptation to OFF, some paretic-side synergies became more dissimilar to their nonparetic-side counterparts. During adaptation to ON, in half of the subjects some paretic-side synergies became closer to their nonparetic references relative to their similarity at FREE as these paretic-side synergies became sparser in muscle components. Across subjects, level of inter-side similarity increase correlated negatively with the degree of gait temporal asymmetry at FREE. Our results demonstrate the possibility that for some survivors, exoskeletal training may promote closer-to-normal muscle synergies. But to fully achieve this, the active force must trigger adaptive processes that offset any undesired synergy changes arising from adaptation to the device’s mechanical properties while also fostering the reemergence of the normal synergies.

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

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

Autonomous Assistance-as-Needed Control of a Lower Limb Exoskeleton With Guaranteed Stability

Abstract: The use of exoskeletons for clinical lower-limb stroke rehabilitation offers the potential of improved and customized rehabilitation that reduces the requirements and demands placed on multiple staff members. Initial research with lower-limb exoskeletons show potential to alleviate this problem. Conventional assistance-based exoskeleton devices simply enforce the desired gait trajectory for the patient in order to ensure safety and stability. Unfortunately, if the end-user does not have to work to contribute to successful motion, rehabilitation often does not occur. Recent evidence has suggested that assistance-as-needed control prevents users from slacking, facilitating functional motor recovery. Assistance-as-needed control turns off assistive torques during periods when the patient is able to execute a desired gait pattern but if the patients gait deviates sufficiently from a desired trajectory then assistive torques are generated to compensate for the patients loss of strength. This strategy encourages the patient to contribute effort while still enabling the exoskeleton to guide movements. Assistance-as-needed control inherently leads to aperiodic gait patterns and has accordingly been difficult to employ in lower-limb exoskeletons due to the need to ensure stability. This work demonstrates how virtual constraint control—a method with robust stability properties used in prostheses and assistive exoskeletons control—can be combined with a velocity-modulated deadzone to ensure stability. Simulations suggest that the method can accommodate a large deadzone while remaining stable across a range of unanticipated gait pathologies, as demonstrated using Lorenz mappings that can accommodate the aperiodic nature of the resulting gait.

Soft Exoskeleton Glove for Hand Assistance Based on Human-machine Interaction and Machine Learning

Abstract: This paper proposes a human machine interaction system in the field of stroke rehabilitation, based on the concept of mirror therapy (MT). It aims to improve the hand motor function of stroke patients, enabling a true synchronization between the affected hand and non-affected hand (healthy hand) for the stroke patient. It consists of a soft exoskeleton glove, a surface electromyography (sEMG) signal collecting armband and machine learning (ML) algorithms. The glove is developed by integrating low-power motors to provide force strength for the hand movement. Unlike the rigid exoskeleton devices, the glove is comfortable to wear and lightweight, so it is more suitable for rehabilitation training of stroke patients in daily life. The armband collects the sEMG signals for pattern recognition by the ML algorithms. In the experiment, four subjects perform 10 hand gestures to collect data for model training. A comparison of data preprocessing is conducted to find the optimal data segmentation method and feature vector sets. A series of pattern recognition algorithms are developed and assessed in different aspects, including prediction accuracy, training time and predicting time. All 10 gestures can be recognized in offline mode with an accuracy up to 99.4%. The control of soft exoskeleton glove in real-time manner is also carried out, and the accuracy is 82.2%. The experiment result demonstrates the feasibility of the proposed system. The innovations and limitations of the work are discussed at the end of the paper.

Task-Based Knee Rehabilitation With Assist-as-Needed Control Strategy and Recovery Tracking System

Abstract: This research aims to design and implement a novel task-based knee rehabilitation strategy through kinematic synthesis, assist-as-needed control strategy, and recovery tracking system. Experimental kinematic data collected through motion capture system are utilized as an input to the mechanism synthesis procedure. Parallel mechanisms with single degree-of-freedom are considered to generate the complex three-dimensional (3D) motions of the lower leg. An exact workspace synthesis approach is utilized, in which the implicit description of the workspace is made to be a function of the structural parameters of the serial chains of the parallel mechanism, making it easy to relate those parameters to the desired trajectory from the motion capture. The synthesis procedure resulted an exoskeleton which can guide the complex motion of the human knee without the need of mimicking the joint by the exoskeleton counterpart. This can potentially reduce the improper alignment problems arising due to the constantly varying axis of rotation of human joint, which is often very difficult to predict. An assist-as-needed control and recovery tracking strategy is outlined based on an electromyography (EMG) signals and force sensing resistors (FSRs) mounted on the user and exoskeleton, respectively. The EMG signal is captured from the user leg and FSRs are applied at the attachment area of the exoskeleton and the leg, this helps to get the amount of force applied by the exoskeleton to the leg as well as for the recovery tracking. The assist-as-needed controller eliminates the need of constant supervision, and hence saves time and reduces cost of the rehabilitation process. Similarly, the real-time progress tracking system will motivate and actively engage users

The utilization of an overground robotic exoskeleton for gait training during inpatient rehabilitation-single-center retrospective findings.

Abstract: Overground robotic exoskeleton gait training is increasingly utilized during inpatient rehabilitation yet without clear guidelines. We describe clinical characteristics associated with robotic exoskeleton gait training and examine outcomes of people with spinal cord injury and stroke who completed usual rehabilitation care with or without robotic exoskeleton gait training. Retrospective review of medical records over a 36 months period. Inpatients with spinal cord injury or stroke and ≥1 robotic exoskeleton gait training session were included. After obtaining a complete list of robotic exoskeleton gait training participants, medical records were reviewed for comparable matches as determined by gait functional independence measure score <4, age 18-100 years, meeting exoskeleton manufacturer eligibility criteria, and participating in usual care only. Functional independence measure was collected on all patients. For spinal cord injury, we collected the walking index for spinal cord injury II. For stroke, we collected the Stroke Rehabilitation Assessment of Movement Measure. Fifty-nine people with spinal cord injury (n = 31 robotic exoskeleton gait training; n = 28 usual care) and 96 people post-stroke (n = 44 robotic exoskeleton gait training; n = 52 usual care) comprised the medical record review. Fifty-eight percent of patients with spinal cord injury and 56% of patients post-stroke completed 5+ robotic exoskeleton gait training sessions and were included in analyses. Robotic exoskeleton gait training dosage varied between our patients with spinal cord injury and patients post-stroke. Robotic exoskeleton gait training utilization during inpatient rehabilitation required consideration of unique patient characteristics impacting functional outcomes. Application of robotic exoskeleton gait training across diagnoses may require different approaches during inpatient rehabilitation.

Towards Neuro-Fuzzy Compensated PID Control of Lower Extremity Exoskeleton System for Passive Gait Rehabilitation

Abstract: The objective of this work is to design a neuro-fuzzy compensated PID control for passive gait rehabilitation using a lower extremity exoskeleton system. A prototype of 6-DOFs exoskeleton device is...

Stable Grasp Control With a Robotic Exoskeleton Glove.

Abstract: An exoskeleton robotic glove intended for patients who have suffered paralysis of the hand due to stroke or other factors has been developed and integrated. The robotic glove has the potential to aid patients with grasping objects as part of their daily life activities. Grasp stability was studied and researched by various research groups, but mainly focused on robotic grippers by devising conditions for a stable grasp of objects. Maintaining grasp stability is important so as to reduce the chances of the object slipping and dropping. But there was little focus on the grasp stability of robotic exoskeleton gloves, and most of the research was focused on mechanical design. A robotic exoskeleton glove was developed as well as novel methods to improve the grasp stability. The glove is constructed with rigidly coupled four-bar linkages attached to the finger tips. Each linkage mechanism has one-DOF (degree of freedom) and is actuated by a linear series elastic actuator (SEA). Two methods were developed to satisfy two of the conditions required for a stable grasp. These include deformation prevention of soft objects, and maintaining force and moment equilibrium of the objects being grasped. Simulations were performed to validate the performance of the proposed algorithms. A battery of experiments was performed on the integrated prototype in order to validate the performance of the algorithms developed.

A Novel Design of a Robotic Glove System for Patients With Brachial Plexus Injuries

Abstract: This paper presents the design of an exoskeleton glove system for people who suffer from the brachial plexus injuries in an effort to restore their lost grasping functionality. The robotic system consists of an embedded controller and a portable glove system. The glove system consists of Linear Series Elastic Actuators (SEA), Rotary SEA and optimized finger linkages to provide motion to each finger and a coupled motion of the hand and the wrist. The design is based on various functionality requirements such as being lightweight and portable for activities of daily living, especially for grasping. The contact force at each fingertip and bending angle of each finger are measured for future implementation of intelligent control algorithms for autonomous grasping. To provide better flexibility and comfort for the users, abduction and adduction of each finger as well as flexion of the thumb were taken into consideration in the design. The glove system is adjustable for different hand sizes. The micro-controllers and batteries are integrated on the forearm in order to provide a completely portable design solution.

Integrated and Configurable Voice Activation and Speaker Verification System for a Robotic Exoskeleton Glove

Abstract: Efficient human-machine interface (HMI) for exoskeletons remains an active research topic, where sample methods have been proposed including using computer vision, EEG (electroencephalogram), and voice recognition. However, some of these methods lack sufficient accuracy, security, and portability. This paper proposes a HMI referred as integrated trigger-word configurable voice activation and speaker verification system (CVASV). The CVASV system is designed for embedded systems with limited computing power that can be applied to any exoskeleton platform. The CVASV system consists of two main sections, including an API based voice activation section and a deep learning based text-independent voice verification section. These two sections are combined into a system that allows the user to configure the activation trigger-word and verify the user’s command in real-time.

HERCULES: A Three Degree-of-Freedom Pneumatic Upper Limb Exoskeleton for Stroke Rehabilitation *

Abstract: This paper outlines the construction, current state, and future goals of HERCULES, a three degree-of-freedom (DoF) pneumatically actuated exoskeleton for stroke rehabilitation. The exoskeleton arm is capable of joint-angle control at the elbow in flexion and extension, at the shoulder in flexion and extension, and at the shoulder in abduction and adduction. In the near future we plan to embed kinematic synergies into the control system architecture of this arm to gain dexterous and near-natural movements.Clinical Relevance— This device can be used as an upper limb rehabilitation testbed for individuals with complete or partial upper limb paralysis. In the future, this system can be used to train individuals on synergy-based rehabilitation protocols.

A Gait Trajectory Control Scheme Through Successive Approximation Based on Radial Basis Function Neural Networks for the Lower Limb Exoskeleton Robot

Abstract: Stability control is critical to the exoskeleton robot controller design. Considering the complex structural characteristics of lower limb exoskeleton robots, the major challenge of the controller design is the accuracy and uncertainty of the dynamics model. To fill in this research gap, this study proposes successive approximation-based radial basis function (RBF) neural networks (NNs). The proposed model simplifies the lower limb exoskeleton robot as three degrees-of-freedom (3-DOF) model with the human hip joints for adduction/extension, bending/extension, and internal/external rotation. To minimize the gait tracking errors and stabilize the closed-loop system, a gait trajectory-based control and approximation model was proposed in this study. To verify the proposed method, a validation experiment was conducted for typical lower limb motions. The experiment results demonstrated the effectiveness of the proposed method.

Design of Fixations for an Exoskeleton Device with Joint Axis Misalignments

Abstract: This study aims to solve problems caused by misalignments between exoskeleton systems and the human body. Misalignments interfere with the achievement of the wearer’s motion intention by generating unintended interaction forces between the wearer and the exoskeleton system. Therefore, this study attempts to overcome this problem by applying an additional degree of freedom (DOF) to the fixation of the human body. First, we analyzed a system of a human body and exoskeleton connected by serial chains. Second, we derived all possible DOF sets for a 7-DOF exoskeleton system and determined the final DOF set based on practical applicability. Finally, we measured the interaction forces generated during the operation of the exoskeleton system to verify the effects of the fixation mechanism. The significance of the results was confirmed by a t test with a significance level of p ≤ 0.05.

Predictive Human-in-the-Loop Simulations for Assistive Exoskeletons

Abstract: Design and evaluation of exoskeletons is often a time consuming and costly process that involves prototyping, human testing, and multiple design iterations. For active exoskeletons, the primary challenge is to detect the wearer’s movement intent and provide potent assistance, which often requires sophisticated control algorithms. The goal of this study is to integrate human musculoskeletal models with robot modeling and control for virtual human-in-the-loop evaluation of exoskeleton design and control. We present potential strategies for assisting various human motions such as squatting, lifting, walking, and running. Several exoskeleton designs (for back, upper extremity, and lower extremity) and their control methods are evaluated with an integrated human-in-the-loop simulation approach to study their functionalities and biomechanical effects on the wearer’ musculoskeletal system. We hope this simulation paradigm can be utilized for virtual design and evaluation of exoskeletons and pave the way to build or optimize exoskeletons.

Switching Operation Modes Algorithm for the Exoskeleton Device

Abstract: Problem statement: For the organization of feedback in the control system of the exoskeleton, information-measuring modules, sensors are essential elements. They allow monitoring the state of the system, to obtain information about the environment, objects of manipulation. Sensors are necessary elements of the master devices that allow evaluating the control signals of the operator. In this paper we propose our algorithm based on mathematical model of human skeletal muscle. Purpose: The movement of the exoskeleton with low speed is necessary to perform any technological operations and it requires increased accuracy of the desired movement. This is especially important when holding or moving heavy cargo or fragile objects. The mode of movement at high speeds allows operator to move quickly the links of the exoskeleton to the desired position in space. This mode is essential for application in situations where frequent changes of direction of movement are taking place and high speeds are required. A feature of this mode is the requirement for a short transition time of the position and speed of the links of the exoskeleton. Results: The algorithm for recognizing the desired action of the operator and selecting the desired mode of operation of the exoskeleton with the adjustment of the characteristics of the task generator was proposed. To obtain reliable experimental data SEMS system was used. The simulation shows that this algorithm improves the quality of control of the exoskeleton drive, using different control formation laws for the corresponding tasks. Practical significance: The field of exoskeleton devices application is determined by the scientific and technical tasks assigned to such systems. The use of exoskeletons is relevant in emergency situations where they are performing tasks related to the movement of heavy loads, ammunition suspension and the implementation of power support while debris removing, repair of agricultural machinery. The carried out researches allows revealing requirements to quality of drive system control of the exoskeleton device applied for any human activity. Various modes of operation of the exoskeleton device were proposed. Each mode should meet the requirements of operations that the operator should perform in the exoskeleton.

Driven type lower limb motion force assisting exoskeleton device

Abstract: The invention discloses a driven type lower limb motion force assisting exoskeleton device. A knee joint force assisting mechanism is included and comprises two knee joint force assisting assemblies,knee joint force assisting assembly thigh connecting discs and shank connecting discs. The thigh connecting discs are provided with first protrusions, and the shank connecting discs are provided withsecond protrusions. A plurality of torsional springs are further included and sleeve the first protrusions and (or) the second protrusions. First limiting protrusions and (or) second limiting protrusions are further included. One ends of the torsional springs serve as fixed ends to be fixed to the thigh connecting discs and (or) the shank connecting discs, the other ends serve as movable ends to abut against the first limiting protrusions and (or) the second limiting protrusions when the relative rotation angle of the thigh connecting discs and the shank connecting discs reaches the set value.By means of the driven type lower limb motion force assisting exoskeleton device, the purposes that assisted force is not provided during walking on the level road, and assisted force is only provided during mountain climbing, stair ascending and descending and other large-angle motions are achieved.

Single Support Phase Gait Kinematics and Kinetics for a Humanoid Lower Limb Exoskeleton

Abstract: The field of assistive robotics has gained increasing importance among robotics and mechatronics researchers in recent years. The use of exoskeleton devices has become popular due to an increase in the number of aged as well as physically weak or injured people and stroke patients. The present work has been initiated, keeping in mind all the challenges faced by them. A 10 Degree of Freedom (DoF) lower-limb exoskeleton device has been considered as the most suitable configuration for an assistive robotic device. At first, a simple 3 DoF two-dimensional bipedal manipulator kinematic and dynamic equations have been derived. This knowledge has been utilized to develop the kinematic model for the Single Support Phase (SSP) of the main exoskeleton system, by dividing it into four parts for ease of tracking the manipulator in real-time, as well as to increase the speed of inverse kinematic calculation. It is essential for a hyper-redundant manipulator. The equations have been validated then with the help of standard software tools (MATLAB Simscape). Finally, human gait biomechanics have been compared with the exoskeleton kinematics and kinetics to validate the simulated observations against analytical values.

Design of a portable anthropomimetic upper limb rehabilitation device for patients suffering from neuromuscular disability

Abstract: An upper limb anthropomimetic rehabilitation device has been designed for patients suffering from a neuromuscular disability. The developed device has been designed as a wearable device and attempts to supplement all known functions of the human hand and fingers. The actuation of individual joints of the hand and wrist has been implemented by using DC motors interfaced to a control system. A pulley system was adopted to ensure a low device profile with the aim of maximising functionality in the affected hand. Both actuators and the electronic assembly are sited in the forearm assembly for this purpose. The device is designed to fulfill multiple roles. At its simplest instance, it is designed as a device for providing resistance training in patients suffering from reversible neuromuscular weakness. The device also aims to provide support as an exoskeleton device in patients suffering from partial but permanent neuromuscular weakness. The measurement of finger and wrist bending in axial and radial directions were investigated by an array of potentiometers mounted around the wearable device covering different joints of the fingers and wrist, and were further analyzed to characterize the range of the device. The system is a composite device with diverse functions fulfilling all the requirements of an upperlimb orthotic device. The device is planned to be part of a comprehensive exoskeleton device for quadriparetic patients in the future.

Modeling of a Novel Lower Limb Exoskeleton System for Paraplegic Patients

Abstract: This paper presents the design of a novel low-cost motorized wheelchair exoskeleton device to provide locomotive assistance and physical rehabilitation to paraplegic patients in the age group of 20–75 years. CAD modeling of different parts of the device has been completed using SOLIDWORKS software. Mathematical calculations are performed to estimate the torque requirements to drive rear wheels, and maximum torque requirement at knees in static condition. Static structural analysis of different parts of the mechanism is performed using ANSYS software for optimization and validation of the proposed design. The reduction in the overall mass of the mechanism is achieved by multi-use of actuators, where a single motor has been used for motion at more than one joints in the device. A mechanism is also designed to allow easy switching of power for the motors from one joint to the other. Further, to make the device eligible for use by people of different heights, adjustability in height of the mechanism has been achieved via the use of telescoping link mechanisms for legs of the device. The aim is to come up with a low-cost device which along with fulfilling the mobility requirements stays light, without compromising the strength and motion capabilities of the device.

Research participation for patients with spinal cord injury.

Abstract: As a patient with spinal cord injury, with C1, C2, and C7 fractures with contusion of the medulla oblongata until the C2 vertebra, I have always felt lonely in my search for the right clinical trials in which I could participate. I believe it is important to have the opportunity to discuss treatment options and patients’ priorities on a regular basis with the treating neurologist or rehab ilitation physician. The possibility for research participation should be a normal part of these conversations. The pervasive culture that there will never be a cure for spinal cord injuries must change. I was surprised to read the statement of Tom Shakespeare and Nicholas Watson in The Lancet Neurology that making environments accessible or provid ing appropriate assistive technology would be more effective than trying to fix individuals with spinal cord injury. Assistive devices are a good option in the short term, but a spinal cord injury implies more problems than not being able to move. My assistive devices could not prevent my current need for haemodialysis. There is no cure for spinal cord injuries at the moment, but there is con tinuous progress in research. Although not all patients will be openminded towards research partici pation, all patients should be well informed about the possibilities to partici pate in methodologically sound clinical trials and the potential benefits and harms of clinical trial partici pa tion. We can not change the future with out research. Furthermore, making research parti ci pation discussable within standard consultations could pre vent patients from seeking unproven cell therapies abroad. When I speak to my health-care providers about participation in trials of functional electrical stimulation, a proven therapy to improve cardiovascular health in patients with spinal cord injury, I can perceive their skepticism in their eyes: why would you do this in your situation? But the only response I can think of is, why not? I would like to participate because I want to pre vent secondary complications from my spinal cord injury, I would like the feeling of movement, and I would like the idea of moving forward instead of resigning myself to my destiny. Furthermore, I want to be prepared for future therapies that might eventually restore part of the damage to my spinal cord. In 2018, several papers reported on the effectiveness of epidural stimu lation in patients with spinal cord injury. Although it is too early to integrate epidural stimulation into routine clinical practice, let’s not make the mistake of leaving the ther apy unavailable for a large part of the target population. It would be unethical to first cheer about a possible breakthrough for patients with a spinal cord injury and not make it available to try afterwards. We know it is not a cure, but until there is a cure, there are are many people who would be happy with small improvements. Not only is research participation imp ort ant, but also is the involvement of patients in determining research prior i ties. Benabid and colleagues have dis cussed the clinical application of a four limb exoskeleton controlled by a brain–machine interface. I do not know if there are many tetraplegic patients looking forward to the use of brain implants to control exoskeletons, which could risk their intellect. Braincontrolled exoskeletons are not a real cure in daily life, but they are in the same category as other less risky assistive technologies. Within a context of scarce financial resources, setting the focus on neuroplasticity and regeneration might be a better option.