• The Journal of Korea Robotics Society
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• v.1 no.1
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• pp.1-8
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• 2006

In this paper, we propose a methodology for classifying types of lower limb disability and their mechanical structure, based on extensive survey of previous developments. We also propose a task-oriented design with human-friendly and energy-efficient assistive system. The result can be used for optimal design of wearable walking-assistive robot considering the type of disability and the content of task.

• Journal of the Ergonomics Society of Korea
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• v.29 no.3
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• pp.357-364
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• 2010

This study proposes a lower-limb exoskeleton system that is controlled by a wearer's muscle activity. This system is designed by following procedure. First, analyze the muscle activation patterns of human leg while walking. Second, select the adequate actuator to support the human walking based on calculation of required force of knee joint for step walking. Third, unit type knee and ankle orthotics are integrated with selected actuator. Finally, using this knee-assistive system (KAS) and developed muscle stiffness sensors (MSS), the muscle activity pattern of the subject is analyzed while he is walking on the stair. This study proposes an operating algorithm of KAS based on command signal of MSS which is generated by motion intent of human. A healthy and normal subject walked while wearing the developed powered-knee exoskeleton on his/her knees, and measured effectively assisted plantar flexor strength of the subject's knees and those neighboring muscles. Finally, capabilities and feasibility of the KAS are evaluated by testing the adapted motor pattern and the EMG signal variance while walking with exoskeleton. These results shows that developed exoskeleton which controlled by muscle activity could help human's walking acceptably.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1379-1380
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• 2010

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.538-546
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• 2015

This paper describes an intelligent ankle assistive robot which provides assistive power to reduce ankle torque based on an analysis of ankle motion and muscle patterns during walking on level and sloped floors. The developed robot can assist ankle muscle power by driving an electric geared motor at the exact timing through the use of an accelerometer that detects gait phase and period, and a potentiometer to measure floor slope angle. A simple muscle assistive link mechanism is proposed to convert the motor torque into the foot assistive force. In particular, this mechanism doesn't restrain the wearer's ankle joint; hence, there is no danger of injury if the motor malfunctions. During walking, the link mechanism pushes down the top of the foot to assist the ankle torque, and it can also lift the foot by inversely driving the linkage, so this robot is useful for foot drop patients. The developed robot and control algorithm are experimentally verified through walking experiments and EMG (Electromyography) measurements.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.4
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• pp.321-328
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• 2016

In this paper, we propose a walk status method which can be fused with conventional walk intention method to improve convenience of an electric assistive walking system for elder people with restricted walking capabilities. The system uses a handlebar as a trigger and regards grabbing a handlebar as expressing will to walk. And the system uses a user's linear velocity and angular velocity as linear velocity and angular velocity of a system, checked by laser range finder. To achieve this, we propose a method to find a virtual central point of a human body by estimating a central point between two legs. The experiments are carried out by comparing user's linear velocity and angular velocity, and system's linear velocity and angular velocity. The results show that the error of linear velocity and angular velocity between a user and a system are 1% and 2.77%, which means the linear velocity and angular velocity of a user can be applied to a system. And it is confirmed that the proposed fusion method can prevent a user from being dragged by an assistive walking system or a malfunction caused by lack of experience

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.223-228
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• 2011

In this paper, we proposed a technique to recognize three states in stance phase of gait cycle. Walking assistive devices are used to help the elderly people walk or to monitor walking behavior of the disabled persons. For the effective assistance, they adopt an intelligent sensor system to understand user's current state in walking. There are three states in stance phase; Loading Response, Midstance, and Terminal Stance. We developed a foot pressure sensor using 24 FSRs (Force Sensing/Sensitive Resistors). The foot pressure patterns were integrated through the interpolation of FSR cell array. The pressure patterns were processed to get the trajectories of COM (Center of Mass). Using the trajectories of COM of foot pressure, we can recognize the three states of stance phase. The experimental results show the effective recognition of stance phase and the possibility of usage on the walking assistive device for better control and/or foot pressure monitoring.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.4 no.1
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• pp.23-28
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• 2010

Case of patients with weakness in cardiopulmonary system, other ambulatory function is normal, but oxygen supply function is problem. So they need reduce energy consumption for gait by assistance system. In this study, we designed and developed walking assistant device which helps flexion and extension of hip joint for cardiopulmonary patients. There are two motors, each at the left and right side of pelvis, providing torque to the hip joint. The target angle of the flexion and extension in the hip joint is set according to the normal gait. As a result, reduction of energy consumption was 14.8% by gait assistive device.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.553-559
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• 2015

The purpose of this research is to develop a gait assistive device to enhance the gait stability and training efficiency of stroke patients. The configuration of this device is mainly composed of a motored wheel and a single cane whose lower end is attached to a motored wheel frame. A patient can feel haptic information from continuous ground contact from the wheel while walking through the grip handle. In addition, the wheeled cane can avoid using excessive use of the patient's upper limb for weight support and motivate the patient to use a paralyzed lower limb more actively. Moreover, the proposed device can provide intuitive and safe user interaction by integrating a force sensor and a tilt sensor equipped to the cane frame, and a switch sensor at the cane's handle. The admittance control has been implemented for the patient to change the walking speed intuitively by using the interaction forces at the handle. A hemi-paretic stroke patient participated in the walking assistive experiments as a pilot study to verify the effectiveness of the proposed haptic cane system. The results showed that the patient could improve walking speed and muscle activations during walking with a constant speed mode of the haptic cane. Moreover, the patient could maintain the preferred walking speeds and gait stability regardless of the magnitude of resistance forces with the admittance control mode of the haptic cane. The proposed robotic gait assistive device with a simple and intuitive mechanism can provide efficient gait training modes to stroke patients with high possibilities of widespread utilizations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.8
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• pp.837-848
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• 2014

This paper describes the development of a walking assistive robot for effective self-rehabilitation for elderly people facing an inconvenience in walking. The main features of the developed robot are enhanced safety and mobility using the baby walker and electric wheelchair mechanisms and an accurate walking tracking control algorithm using potentiometers and stereo cameras. Specifically, a pelvis supporter is designed to prevent the user from falling down and reduce the burden on their legs, and electric motors are used for easy locomotion with low effort. Next, the walking intention and direction of the user are automatically recognized by using potentiometers attached at the pelvis supporter so that the robot can track the user, and the rapidity and accuracy of the tracking were increased by applying a lower-body motion analysis algorithm with stereo cameras. Finally, the user-tracking performance of the developed robot was experimentally verified through stepwise walking assistance experiments.

• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.152-162
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• 2024

Objective: This study was conducted to analyze the effect of wearable Electromyography-controlled functional electrical stimulation (EMG-controlled FES) System on Gait Function and cardiopulmonary metabolic efficiency during walking in older adults. Design: Cross-section study Methods: Total 22 older adult participants suitable to selection criteria of this study participated in this study. The EMG-controlled FES System, which functions as a wearable physical activity assist FES system was used. All participations performed randomly assigned two conditions (Non-FES assist [NFA], FES assist [FA]) of walking. In all conditions, spatio-temporal parameters and kinematics and kinetics parameters during walking was collected via 3D motion capture system and 6 minutes walking test (6MWT) and metabolic cost during walking and stairs climbing was collected via a portable metabolic device (COSMED K5, COSMED Srl, Roma, Italy). Results: In Spatio-temporal parameters aspects, The EMG-controlled FES system significantly improved gait functions measurements of older adults with sarcopenia at walking in comparison to the NFA condition (P<0.05). Hip, knee and ankle joint range of motion increased at walking in FA condition compared to the NFA condition (P<0.05). In the FA condition, moment and ground reaction force was changed like normal gait during walking of older adults in comparison to the NFA condition (P<0.05). The EMG-controlled FES system significantly reduced net cardiopulmonary metabolic energy cost, net energy expenditure measurement at stairs climbing (P<0.05). Conclusions: This study demonstrated that EMG-controlled FES is a potentially useful gait-assist system for improving gait function by making joint range of motion and moment properly.