Exoskeleton For Upper Limb Rehabilitation Research Articles

Multi-Sensor Fusion-Based Mirror Adaptive Assist-as-Needed Control Strategy of a Soft Exoskeleton for Upper Limb Rehabilitation

Multi-Sensor Fusion-Based Mirror Adaptive Assist-as-Needed Control Strategy of a Soft Exoskeleton for Upper Limb Rehabilitation

Robotic digital twin as a training platform for rehabilitation health personnel

In the last twenty years, a trend towards the digitization of products and processes has been generated, so the new concept of health 4.0 promotes the use of simulators and digital twins for the training of health personnel, as well as for the personalized planning of patients rehabilitation treatments. This paper presents a virtual training tool for health personnel, which is based on the prototype of a digital twin of an exoskeleton for upper limb rehabilitation. The device was designed in Solidworks® and later its equivalent model was obtained in Matlab/Simulink® software. Through the latter, the functionality of the device is evaluated through the implementation of different therapeutic routines, which help the physiotherapist to plan and evaluate the performance of each patient’s treatment. In this case, the evaluation of the movements of the upper limb are generated through independent and combined movements of the shoulder,elbow and wrist joints and, as a result, graphs of the movements are obtained, , as well as a virtual representation of the digital twin and the values of the torques in each joint. Finally, a digital tool that allows the digital twin prototype to be configured to conditions similar to those of the real exoskeleton for automation and supervision tasks is obtained.

Assessing the Social and Environmental Impact of Healthcare Technologies: Towards an Extended Social Return on Investment

Stroke is the third leading cause of death and disability overall worldwide. Upper limb impairment is a common consequence for stroke survivors, having negative impact on their quality of life. Robotic rehabilitation, through repetitive and monitored movements, can improve their status. Developed by a team of researchers at Politecnico di Milano, AGREE is an exoskeleton for upper limb rehabilitation at the stage gate between translational research and clinical validation. Since the cost of this device is particularly high, the present study aimed to provide a framework for assessing its value. The Social Return on Investment (SROI) method, able to grasp the economic, social and environmental impact of an activity, was applied, using expert opinions of a pool of clinical engineers and healthcare professionals from different Italian hospitals to obtain information. Environmental impacts were estimated through Life Cycle Assessment in terms of CO2 emissions and incorporated in the analysis. Considering a 5-year period, the SROI for a single exoskeleton was 3.75:1, and the SROI for the number of exoskeletons projected to be sold was 2.868:1, thus resulting largely in value for money. This study provides a model for combining economic, social and environmental outcomes that, besides contributing to theory, could be useful for decision-making.

CLEVERarm: A Lightweight and Compact Exoskeleton for Upper-Limb Rehabilitation

This letter presents the electromechanical design, system architecture, baseline control development, and the preliminary evaluation of a novel upper-limb exoskeleton, named CLEVERarm. The developed system can support the motions of inner shoulder, glenohumeral joint, elbow and wrist’s pronation/supination and flexion/extension. Enhanced portability, design robustness, and ergonomic performance are chosen as the pillars of the design. These qualities are selected due to their importance for enabling exoskeletons’ use outside the clinical and research setting. CLEVERarm’s links are manufactured using carbon-fiber-reinforced 3D-printed plastic to achieve a lightweight and compact design. For design robustness, minimizing maintenance requirements are taken into account in the selection and placement of actuation, sensing and controller components. Finally to realize an ergonomic interaction, inner shoulder motions are supported by a back-drivable motorized design, controlled by an impedance controller. This architecture enables accommodating natural variations in scapulohumeral rhythm among users. The performance of the developed exoskeleton is evaluated using experiments involving healthy subjects. It is shown that despite its lightweight, CLEVERarm is structurally stiff and supports a large subset of the healthy range of motion. Additionally, experimental results confirming the performance of the baseline controller are presented.

CardioVR-ReTone—Robotic Exoskeleton for Upper Limb Rehabilitation following Open Heart Surgery: Design, Modelling, and Control

Following cardiac surgery, patients experience difficulties with the rehabilitation process, often finding it difficult, and therefore lack the motivation for rehabilitation activities. As the number of people aged 65 and over will rise by 207 percent globally by 2050, the need for cardiac rehabilitation will significantly increase, as this is the main population to experience heart problems. To address this challenge, this paper proposes a new robotic exoskeleton concept with 12 DoFs (6 DoFs on each arm), with a symmetrical structure for the upper limbs, to be used in the early rehabilitation of cardiac patients after open-heart surgery. The electromechanical design (geometric, kinematic, and dynamic model), the control architecture, and the VR-based operating module of the robotic exoskeleton are presented. To solve the problem of the high degree of complexity regarding the CardioVR-ReTone kinematic and dynamic model, the iterative algorithm, kinetic energy, and generalized forces were used. The results serve as a complete model of the exoskeleton, from a kinematic and dynamic point of view as well as to the selection of the electric motors, control system, and VR motivation model. The validation of the concept was achieved by evaluating the exoskeleton structure from an ergonomic point of view, emphasizing the movements that will be part of the cardiac rehabilitation.

Validation of a Hybrid Exoskeleton for Upper Limb Rehabilitation. A Preliminary Study.

Recovery of therapeutic or functional ambulatory capacity in patients with rotator cuff injury is a primary goal of rehabilitation. Wearable powered exoskeletons allow patients to perform repetitive practice with large movements to maximize recovery, even immediately after the acute event. The aim of this paper is to describe the usability, acceptability and acceptance of a hybrid exoskeleton for upper-limb passive rehabilitation using the System Usability Scale (SUS) questionnaire. This equipment, called ExoFlex, is defined as a hybrid exoskeleton since it is made up of rigid and soft components. The exoskeleton mechanical description is presented along with its control system and the way motion is structured in rehabilitation sessions. Seven patients (six women and one man) have participated in the evaluation of this equipment, which are in the range of 50 to 79 years old. Preliminary evidence of the acceptance and usability by both patients and clinicians are very promising, obtaining an average score of 80.71 in the SUS test, as well as good results in a questionnaire that evaluates the clinicians’ perceived usability of ExoFlex.

Compatibility evaluation of a 4-DOF ergonomic exoskeleton for upper limb rehabilitation

Due to their advantages of high durability, low labor intensiveness and high repeatability, upper limb exoskeletons have become promising tools in stroke rehabilitation. The act of decreasing the undesired interactional loads caused by exoskeleton incompatibility remains an enormous challenge in the design of ergonomic exoskeletons. In this article, a novel 4-DOF upper limb exoskeleton that is kinematically compatible with the upper limb is proposed. A prototype of the proposed exoskeleton was developed. Subsequently, the interaction forces, torques and displacements at the physical human-exoskeleton connection interfaces were detected under static and dynamic modes to quantitatively evaluate the compatibility of the exoskeleton. The results indicated that the proposed exoskeleton can significantly decrease the undesired interactional load at the connective interfaces, and its ergonomic design was found to be effective; thus, this exoskeleton may be used for the rehabilitation of human upper limbs.

Design Methodology for Rehabilitation Robots: Application in an Exoskeleton for Upper Limb Rehabilitation

This article presents a methodology for the design of rehabilitation devices that considers factors involved in a clinical environment. This methodology integrates different disciplines that work together. The methodology is composed by three phases and 13 stages with specific tasks, the first phase includes the clinical context considering the requirements of the patient and therapist during the rehabilitation, the second phase is focused in engineering based on the philosophy of digital twin, and in the third phase is evaluated the device. This article explains the characteristics of the methodology and how it was applied in the design of an exoskeleton for passive rehabilitation of upper limb.

Cable driven exoskeleton for upper-limb rehabilitation: A design review

One of the primary reasons for long-term disabilities in the world is strokes. The causes of these cerebrovascular diseases are various, i.e., high blood pressure, heart disease, etc. For those who survive strokes, this affectation causes loss in the mobility of extremities, requiring the intervention of long sessions with a therapeutic professional to recover the movement of the impair limb. Hence, the investment to threaten this condition is usually high, motivating researchers to implements exoskeletons in the rehabilitation process. Those devices permit the user means to conduct the therapies without the constant supervision of a professional. Furthermore, exoskeletons are capable of maintaining a detailed recording of the forces and movements developed for the patients throughout the session. However, the construction of an exoskeleton is not cheap principally for the actuation systems, especially if the exoskeleton requires the actuator to be placed at the joints of the user; in which, the actuator at a joint would have to withstand the load of the actuator of the following joint and so on.Researchers have addressed this drawback by applying cable transmission systems that allow the exoskeleton to place their actuator at a fixed base, reducing the weight of their design, and decreasing their cost. Thus, this paper reviews the principal models of cable-driven exoskeleton for stroke rehabilitation focusing on the upper-limb. The analysis departs from the study of the anatomy of the arm, including the shoulder, elbow, wrist, fingers, and thumb. Besides, it also includes the mechanical consideration to design a proper exoskeleton. Then, the article presents a compendium of the different transmission systems found in the literature, addressing their advantages, disadvantages and their requirements for the design. Lastly, the paper reviews the cable-driven exoskeleton for stroke rehabilitation of the upper limb. Again, for this analysis, it is included the design consideration of each prototype, focusing on their advantages in terms of anatomical mechanics.

Pilot Study of a Powered Exoskeleton for Upper Limb Rehabilitation Based on the Wheelchair.

To help hemiplegic patients with stroke to restore impaired or lost upper extremity functionalities efficiently, the design of upper limb rehabilitation robotics which can substitute human practice becomes more important. The aim of this work is to propose a powered exoskeleton for upper limb rehabilitation based on a wheelchair in order to increase the frequency of training and reduce the preparing time per training. This paper firstly analyzes the range of motion (ROM) of the flexion/extension, adduction/abduction, and internal/external of the shoulder joint, the flexion/extension of the elbow joint, the pronation/supination of the forearm, the flexion/extension and ulnar/radial of the wrist joint by measuring the normal people who are sitting on a wheelchair. Then, a six-degree-of-freedom exoskeleton based on a wheelchair is designed according to the defined range of motion. The kinematics model and workspace are analyzed to understand the position of the exoskeleton. In the end, the test of ROM of each joint has been done. The maximum error of measured and desired shoulder flexion and extension joint angle is 14.98%. The maximum error of measured and desired elbow flexion and extension joint angle is 14.56%. It is acceptable for rehabilitation training. Meanwhile, the movement of drinking water can be realized in accordance with the range of motion. It demonstrates that the proposed upper limb exoskeleton can also assist people with upper limb disorder to deal with activities of daily living. The feasibility of the proposed powered exoskeleton for upper limb rehabilitation training and function compensating based on a wheelchair is proved.

An Elbow Exoskeleton for Upper Limb Rehabilitation With Series Elastic Actuator and Cable-Driven Differential

Movement impairments resulting from neurologic injuries, such as stroke, can be treated with robotic exoskeletons that assist with movement retraining. Exoskeleton designs benefit from low impedance and accurate torque control. We designed a 2 degree-of-freedom tethered exoskeleton that can provide independent torque control on elbow flexion/extension and forearm supination/pronation. Two identical series elastic actuators (SEAs) are used to actuate the exoskeleton. The two SEAs are coupled through a novel cable-driven differential. The exoskeleton is compact and lightweight, with a mass of 0.9 kg. Applied RMS torque errors were less than 0.19 Nm. Benchtop tests demonstrated a torque rise time of approximately 0.1 s, a torque control bandwidth of 3.7 Hz and an impedance of less than 0.03 Nm/deg at 1 Hz. The controller can simulate a stable maximum wall stiffness of 0.45 Nm/deg. The overall performance is adequate for robotic therapy applications and the novelty of the design is discussed.

Design and control of an ergonomic robotic shoulder for wearable exoskeleton robot for rehabilitation

In this paper, we present an ergonomic robotic shoulder for upper limb exoskeleton. Most exoskeletons have been designed considering shoulder joint instantaneous center of rotation (ICR)—often termed as the center of glenohumeral joint—as fixed joint. In reality, shoulder joint ICR does move during shoulder abduction–adduction and vertical flexion–extension. The abduction–adduction causes shoulder joint ICR to move in the frontal plane, resulting from a combined motion of shoulder depression–elevation and horizontal translation, while vertical flexion–extension produces a movement of shoulder protraction–retraction. If these additional motions are not compensated in exoskeleton design, they can produce discomfort and/or pain to the robot’s wearer. While in most of the exoskeleton, shoulder joint articulation is considered as a 3-DOFs spherical joint, this research proposes a novel shoulder joint mechanism of robotic exoskeleton with two additional passive DOFs to provide ergonomic shoulder movement. The mechanisms in proposed robotic shoulder comprises of two sliders that allow above-mentioned passive movements of shoulder joint ICR. In this research, we demonstrated that the slider-1 enables shoulder joint ICR to move in the frontal plane with a quarter circular arc of 60 mm during abduction–adduction, while slider-2 allows movement of shoulder protraction–retraction as needed. Proposed mechanism has been designed to be used eventually in a 7 DOF modular robotic exoskeleton for upper limb rehabilitation. We have also applied computed torque control (CTC) to the designed shoulder. The performance of CTC shows stability and effectiveness.

Servo-assisted Control of a 7-DOF Exoskeleton for Upper Limb Rehabilitation

This paper reviews the research on upper limb exoskeleton for hemiplegia rehabilitation. Under the condition of rehabilitation training for mild patients in the workspace of 7-DOF exoskeleton with uncertain trajectory, a control algorithm used for motion detection is carried. In this algorithm, the patient’s operation can be detected by real-time data collected by F/T (Force/Torque) sensors and encoders, so that quantitative assistance will be supplied by exoskeleton according to the patient’s motion intention. Finally, the joint simulation of ADAMS and MATLAB proves the accuracy of trajectory tracking and the feasibility of the control strategy is verified by the experiment on 3-DOF translational manipulator platform.

Experimental Evaluation of a Mixed Controller That Amplifies Spatial Errors and Reduces Timing Errors

Research on motor learning suggests that training with haptic guidance enhances learning of the timing components of motor tasks, whereas error amplification is better for learning the spatial components. We present a novel mixed guidance controller that combines haptic guidance and error amplification to simultaneously promote learning of the timing and spatial components of complex motor tasks. The controller is realized using a force field around the desired position. This force field has a stable manifold tangential to the trajectory that guides subjects in velocity related aspects. The force field has an unstable manifold perpendicular to the trajectory, which amplifies the perpendicular (spatial) error. We also designed a controller that applies randomly-varying, unpredictable disturbing forces to enhance the subjects’ active participation by pushing them away from their “comfort zone.” We conducted an experiment with thirty-two healthy subjects to evaluate the impact of four different training strategies on motor skill learning and self-reported motivation: i) No haptics, ii) mixed guidance, iii) perpendicular error amplification and tangential haptic guidance provided in sequential order, and iv) randomly-varying disturbing forces. Subjects trained two motor tasks using ARMin IV, a robotic exoskeleton for upper limb rehabilitation: Follow circles with an ellipsoidal speed profile, and move along a 3D line following a complex speed profile. Mixed guidance showed no detectable learning advantages over the other groups. Results suggest that the effectiveness of the training strategies depends on the subjects’ initial skill level. Mixed guidance seemed to benefit subjects who performed the circle task with smaller errors during baseline (i.e. initially more skilled subjects), while training with no haptics was more beneficial for subjects who created larger errors (i.e. less skilled subjects). Therefore, perhaps the high functional difficulty of the tasks limited the potential benefit of mixed guidance. Adding random disturbing forces during training reduced the learning effect size compared to no haptics. The unanticipated forces also decreased the subjects’ feelings of competence while did not increase their effort and interest. Further studies with mildly affected neurologically patients employing easier tasks need to be performed in order to evaluate the applicability of our approaches in rehabilitation.

Prototype Construction of the Wearable Soft Orthotic Exoskeleton for Upper Limb Rehabilitation of Post-Stroke Patients

Prototype Construction of the Wearable Soft Orthotic Exoskeleton for Upper Limb Rehabilitation of Post-Stroke Patients

Design of a Rotational Hydroelastic Actuator for a Powered Exoskeleton for Upper Limb Rehabilitation

The goal of this study was to validate the suitability of a novel rotational hydroelastic actuator (rHEA) for use in our new rehabilitation exoskeleton for the upper limbs, the Limpact. The rHEA consists of a rotational hydraulic actuator and a custom-designed symmetric torsion spring in a series-elastic configuration. For rehabilitation therapy and impairment quantification, both compliant impedance control and stiff admittance control modes are possible. In the validation experiments, the torque bandwidth of the rHEA was limited to 18 Hz for a desired 20 N m reference signal (multisine, constant spectrum) due the transport delays in the long flexible tubes between the valve and cylinder. These transport delays also required changes to existing theoretical models to better fit the models on the measured frequency response functions. The (theoretical) measurable torque resolution was better than 0.01 N m and the (validated) delivered torque resolution below 1 N m. After the validation experiments, further iterative improvements resulted in a spring design capable of a maximum output torque of 50 N m with an intrinsic stiffness of 150 N . m/rad and a slightly higher bandwidth. With the design locked, the maximum measurable isometric torque is 100 N m. In conclusion, the rHEA is suitable for upper limb rehabilitation therapy as it matches the desired performance.