Wearable exoskeleton robot design

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2007Includes bibliographical references (leaves: 81-82)Text in English; Abstract: Turkish and Englishxi, 94 leavesIn this thesis study it is intended to design a wearable exoskeleton robot which will replace paralytic or disable people.s legs and provide to walk. The wearable exoskeleton robot will be an intelligent system that fulfill the gait necessities, climb the slopes up and down, and remove the disadvantages of the wheelchairs and mobility aid vehicles. Robot will be a wearable device like a trouser and it will work to carry out daily duties for users. Robot will increase user.s maneuver capabilities and support users. legs and aid walking action for users thanks to 3-one degree of freedom (DOF) joints which are designed for each leg and are powered by DC electric actuators. Design of the wearable exoskeleton robot includes, modeling and designing of the robot using a parametric solid modeling computer program (Solidworks), selection of the most suitable material for the design characters and robot manufacturing processes, strength analysis of the critical part of the robot, mathematical modeling of the system, design and manufacturing of the test machine and finding the most suitable walking combination by investigating degree of freedoms of each joints on the legs. In addition to mechanical design of the wearable exoskeleton robot, an electronic circuit is designed and manufactured in order to control each joint movement order and time in walking action. Moreover, in order to control the robot by the users, a keypad unit is manufactured on the robot and necessity functions are described in the program. As a result of this thesis; a wearable exoskeleton robot is manufactured to be used as a walking assistant

A Review of Lower Limb Exoskeletons

In general, exoskeletons are defined as wearable robotic mechanisms for providing mobility. In the last six decades, many research work have been achieved to enhance the performance of exoskeletons thus developing them to nearly commercialized products. In this paper, a review is made for the lower limb exoskeleton concerning history, classification, selection and development, also a discussion for the most important aspects of comparison between different designs is presented. Further, some concluding remarks are withdrawn which could be useful for future work. Keywords: Exoskeletons, Lower extremity exoskeleton, Wearable robot

Robot-assisted voluntary initiation reduces control-related difficulties of initiating joint movement: A phenomenal questionnaire study on shaping and compensation of forward gait

Humans employ various control strategies to initiate and maintain bodily movement. In case that the normal gait function is impaired, exoskeleton robots provide motor assistance during therapy. While the robotic control system builds on kinematic gait functions, the patient’s voluntary efforts to initiate motion also contribute to the effectiveness of the therapy process. However, it is currently not well understood how voluntary initiation as a subjective capacity affects the physiological level of motor control. In order to understand the functional nexus between voluntary initiation and motor control, we interviewed patients undergoing robotic gait rehabilitation with the HAL exoskeleton robot about their experience and command of voluntarily initiating forward gait while using the HAL system. Their reports provide phenomenal evidence for voluntary initiation as a distinct cognitive act that comes as phenomenal performance. Furthermore, phenomenal evidence about the functional relation of intention and initiation correlates with FIM-M gait scores. Based on the assumption that HAL reduces control-related difficulties of voluntarily initiating joint movement, we identified two cognitive control strategies, shaping and compensation of gait, that imply a heterarchic organization of the human system of action control

Simulation and design of an active orthosis for an incomplete spinal cord injured subject

The dynamic simulation of incomplete spinal cord injured individuals equipped with active orthoses is a challenging problem due to the redundancy of the simultaneous human-orthosis actuation. The objective of this work is two-fold. Firstly, a physiological static optimization approach to solve the muscle-orthosis actuation sharing problem is presented. For this purpose, a biomechanical model based on multibody dynamics techniques is used. The muscles are modeled as Hill-type actuators and the atrophy of denervated muscles is considered by adding stiff and dissipative elements. Secondly, the mechanical design of a new active stance-control knee-ankle-foot orthosis (A-SCKAFO) is addressed. The proposed device consists of a passive joint that constrains ankle plantar flexion, along with a powered knee unit that prevents flexion during stance and controls flexion-extension during swing. The knee actuation is selected based on the results obtained through the optimization approach.Peer ReviewedPostprint (published version

EMG-based motion intention recognition for controlling a powered knee orthosis

Powered assistive devices have been playing a major role in gait rehabilitation. This work aims to develop a user-oriented assistive strategy with an EMG-based control using a powered knee orthosis (PKO) to provide assistive commands according to the user's motion intention tracked by electromyography (EMG) signals. To achieve this goal, the work first comprised the development of a wired EMG acquisition system, the study and implementation of a knee joint torque estimation method, and the development of a real-time controller, which uses the estimated torque as the reference actuator's torque to provide user-oriented assistance in walking. We used a proportional gain method to estimate the knee torque, which required a calibration procedure, allowing to determine the relation between the EMG signal and the actuator's torque. The EMG-based control was validated with two subjects walking in a treadmill. The EMG-based control performed as expected since it proved to be functional and time-effective when assisting the user's movements in walking at different walking speeds. Findings show that the developed assistive strategy can effectively follow the user's motion intention and has the potential for gait rehabilitation of patients with residual muscular strength.This work has been supported in part by the Fundacao para a Ciencia e Tecnologia (FCT) with the Reference Scholarship under Grant SFRH/BD/108309/2015, the reference project UID/EEA/04436/2019, by FEDER funds through the COMPETE 2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) - with the reference Project POCI-01-0145-FEDER-006941; and the LIACC Project UID/CEC/00027/2019; and with national funds from FCT project SmartOs-under Grant NORTE-01-0145-FEDER-030386

Feasibility and efficacy of incorporating an exoskeleton in gait training during subacute stroke rehabilitation

Introduction: Hemiparesis is the most common acute manifestation of stroke and often has a strong negative impact on walking ability leaving one third of patients dependent in walking activities outside one’s home. Improved methods for training of gait during stroke rehabilitation could tackle the challenge of achieving independent walking and promote better outcomes. Several studies have explored the value of introducing electromechanical gait machines in stroke rehabilitation to enhance gait training. One example is the exoskeleton Hybrid Assistive Limb (HAL). The HAL system has been found feasible to use during rehabilitation in the chronic stage after stroke, however knowledge of the feasibility in the subacute stage after stroke and its efficacy compared to evidence-based conventional gait training is still limited. Aim: The overall aim of this thesis was to evaluate the safety and feasibility of HAL for gait training in the subacute stage after stroke and the effect of HAL training on functioning, disability and health compared to conventional gait training, as part of an inpatient rehabilitation program in patients with severe limitations in walking in the subacute stage after stroke. Methods: This thesis contains two studies where one is a safety and feasibility study (Study I) and one is a prospective, randomized, open labeled, blinded evaluation study (Study II). In Study I, eight patients performed HAL training 5 days/week. The number of training sessions were adjusted individually and varied from 6 to 31 (median 16). Safety and feasibility aspects of the training were evaluated as well as clinical outcomes on functioning and disability (e.g. independence in walking, walking speed, balance, movement functions and activities of daily living), assessed before and after the intervention period. In Study II, 32 patients were randomized to either conventional training only or HAL training in addition to the conventional training, 4 days per week for 4 weeks. Within and between- group differences in independence in walking, walking speed/endurance, balance, movement functions and activities of daily living were investigated before and after the intervention period, as well as 6 months post stroke. In addition, gait pattern functions were evaluated after the intervention in a three-dimensional gait laboratory. At 6 months post stroke self- perceived aspects on functioning disability and health were assessed and subsequently correlated to the clinical assessments. Results: In Study I HAL was found to be safe and feasible for gait training after stroke in patients with hemiparesis, unable to walk independently, undergoing an inpatient rehabilitation program. All patients improved in walking independence and speed, movement function, and activities of daily living during the intervention period. In addition, it was found that patients walked long distances during the HAL sessions, suggesting that HAL training may be an effective method to enhance gait training during rehabilitation of patients in the subacute stage after stroke. In Study II substantial but equal improvements in the clinically evaluated outcomes in the two intervention groups were found. At six months post stroke, two thirds of patients were independent in walking, and a younger age but not intervention group served as the best predictor. Gait patterns were similarly impaired in both groups and in line with previous reports on gait patterns post stroke. Further, self-perceived ratings on functioning, disability and health were explained by the ability to perform self-care activities and not by intervention group. Conclusion: To incorporate gait training with HAL is safe and feasible during inpatient rehabilitation in the subacute stage after stroke and may be a way to increase the dose (i.e. number of steps) in gait training in the subacute stage after stroke. Among these included younger patients with hemiparesis and severe limitations in walking in the subacute stage after stroke, substantial improvements in body function and activity as well as equally impaired gait patterns were observed both after incorporated HAL training and after conventional gait training only, but without between-group differences. In future studies, potential beneficial effects on cardiovascular, respiratory, and metabolic functions should be addressed. Further, as the stroke population is heterogeneous, potential subgroups of patients who may benefit the most from electromechanically-assisted gait training should be identified

Immediate Effect of Elastic Taping Application on Gait Functional Ability in Patients with Stroke

Background: The typical consequence of a stroke is the limitation in walking ability. In stroke patients, there is a disruption of mobilization, including walking. Stroke patients exhibit abnormal walking patterns as compensation for muscular weakness. Elastic taping known to increase functional movement through increased muscle strength In addition; elastic taping helps maintain muscle coordination of agonists, synergists, and antagonists. Objective: Determine the immediate effect of elastic tape on the gait functional ability in post stroke patient with ankle dorsiflexor muscle weakness. Method: This research is an experimental pre-post study. The total subjects are 11 patients with hemiparesis following stroke. The gait speed, step length and stride length measured by gait analysis lab with CMAX gait software, before and after the elastic tape application for 30 minutes. Leukotape K® was applied with facilitation technique on the anterior tibial and extensor digitorum longus, from the origin to the insertion with 100% of stretch. Result: The gait speed and step length on healthy side after 30 minutes elastic tape increased when compared with the pre-application value (p>0.05). Conclusion: There is an increment of gait speed and step length on healthy side in post-stroke patients with ankle dorsiflexor weakness after 30 minutes elastic taping application. Elastic taping may be beneficial in treating gait functional disturbances in post-stroke patients