• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1044-1051
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• 2004

This paper described a novel locomotion interface that can generate infinite floor for various surface, named as virtual walking machine. This interface allows users to participate in a life-like walking experience in virtual environments, which include various terrains such as plains, slopes and stair ground surfaces. The interface is composed of two three-DOF (X, Y, Yaw) planar devices and two four-DOF (Pitch, Roll, Z, and relative rotation) footpads. The planar devices are driven by AC servomotors for generating fast motions, while the footpad devices are driven by pneumatic actuators for continuous support of human weight. To simulate natural human walking, the locomotion interface design specification are acquired based on gait analysis and each mechanism is optimally designed and manufactured to satisfy the given requirements. The designed locomotion interface allows natural walking(step: 0.8m, height: 20cm, load capability: 100kg, slope:30deg) for various terrains.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.373-381
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• 2009

In this paper, a humanoid robot is simulated and implemented to walk up a staircase using the blending polynomial and genetic algorithm. Using recently developed kinematics for a biped robot, four schemes for walking up a staircase are newly proposed and simulated separately. For the two schemes of landing a swaying leg on the upper stair, the joint trajectories of seven motors are particularly optimized to generate an energy-minimal motion with the guarantee of walking stability. The proposed scheme of walking upstair is validated by an experiment with a small humanoid robot.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.825-837
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• 2017

This paper describes a novel type of a walking rehabilitation robot that applies robot technologies to crutches used by patients with walking difficulties in the lower body. The primary features of the developed robot are divided into three parts. First, the developed robot is worn on the patient's chest, as opposed to the conventional elbow crutch that is attached to the forearm; hence, it can effectively disperse the patient's weight throughout the width of the chest, and eliminate the concentrated load at the elbow. Furthermore, it allows free arm motion during walking. Second, the developed robot can recognize the walking intention of the patient from the magnitude and direction of the ground reactive forces. This is done using three-axis force sensors attached to the feet of the robot. Third, the robot can perform a stair walking function, which can change vertical movement trajectories in order to step up and down a single stair according to the floor height. Consequently, we experimentally showed that the developed robot can effectively perform walking rehabilitation assistance by perceiving the walking intention of the patient. Moreover we quantitatively verified muscle power assistance by measuring the electromyography (EMG) signals of the muscles of the lower limb.

• Korean Journal of Applied Biomechanics
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• v.20 no.3
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• pp.267-275
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• 2010

The purpose of this study was to investigate the effects of balance ability improvement exercise program which applied to the elderly people for increasing balance, stability and range of motion. Ten elderly people and ten university students were recruited as the subjects. Kinematic data were collected by seven real-time infrared cameras while subjects walk stair descent as a pre-test. Korean folk dance exercise program was applied to the elderly for 12 weeks. Same experiment on stair descent walk was performed as post-test. Results indicated that CM movement and selected joint angle patterns of elderly group after treatment changed to the similar patterns of young group. However, ankle joint angle and vertical GRF of elderly group after treatment also increased compared to those of the elderly group before treatment. This might be explained by the fact that elderly used a different walking strategy which maximize support base for increasing stability. Overall, these results indicated that the exercise treatment may affect to adapt and improve the gait pattern of stair descent of elderly people.

• 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.

• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.32-39
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• 2021

Objective: The weakness of muscle strength due to stroke affects the posture control and gait in the patients with stroke. Stroke This study examined the effects of the stair climbing training with functional electrical stimulation on muscle strength, dynamic balance, and gait in individuals with chronic stroke. Design: Randomized controlled trial. Methods: Total forty-eight patients were randomly assigned to the 3 groups. Participants randomly divided to stair climbing training with functional electrical stimulation group (SCT+FES group, n=16), stair climbing training group (SCT group, n=16) and control group (n=16). Subjects in the SCT+FES group and SCT group performed stair walking training with and without functional electrical stimulation for 30 minutes, 3 sessions per week for 4 weeks and all subjects received conventional physical therapy for 30 minutes with 5 sessions per week for 4 weeks. Outcome measurements were assessed using the sit-to stand Test for strength, timed up and go test and modified-timed up and go test for dynamic balance, and 10m walk test and GaitRite system for gait. Results: In the SCT+FES group, subjects have been shown the significant increase in lower extremity strength (p<0.05), significantly improve in dynamic balance (p<0.05), and significantly improve in their temporal gait parameter (p<0.05). The SCT+FES group was significantly better than other groups in all parameters (p<0.05). Conclusions: This result suggested that the SCT+FES may be effective strategy to improve muscle strength, dynamic balance, and gait for individuals with chronic stroke.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1059-1060
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• 2008

In this paper, using a genetic algorithm, consisting of six to seven degrees of freedom links, walking robot to up-stair that can walk to optimize energy and stability to generate. Walking robot to up-stairs of the four-step segmentation of the various situations that match the pace and pattern so that it can generate. It also generated using genetic algorithms to test for Matlab into the Robot Simulation of the humanoid experiment was used.

• The Journal of Korean Physical Therapy
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• v.21 no.1
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• pp.35-40
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• 2009

Purpose: The purpose of this study was to investigate change of muscle activities during level walking, stairs and ramp climbing in old adults. Methods: Twelve old adults were recruited and agreed this study. Muscle activity was measured by MP150 system (BIOPAC System Inc., Santa Barbara, USA). Statistical analysis was used one-way ANOVA to know the difference according to gait conditions (level walking, stairs and ramp ascending) Results: In stance phase, muscle activities of low extremities with old adults were generally significant difference in ramp ascending. In swing phase, rectus femoris and biceps femoris activity in old adults generally more increased during stairs ascending and tibialis anterior and gastrocnemius activity in old adults generally increased during ramp ascending. Conclusion: These results indicate that stair and ramp climbing is different muscle recruit pattern to level walking.

• The Journal of Korea Robotics Society
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• v.18 no.2
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• pp.182-188
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• 2023

Due to the acceleration of an aging society, the need for lower limb exoskeletons to assist gait is increasing. And for use in daily life, it is essential to have technology that can accurately estimate gait phase even in the walking environment and walking speed of the wearer that changes frequently. In this paper, we implement an LSTM-based gait phase estimation learning model by collecting gait data according to changes in gait speed in outdoor level ground and stair environments. In addition, the results of the gait phase estimation error for each walking environment were compared after learning for both max hip extension (MHE) and max hip flexion (MHF), which are ground truth criteria in gait phase divided in previous studies. As a result, the average error rate of all walking environments using MHF reference data and MHE reference data was 2.97% and 4.36%, respectively, and the result of using MHF reference data was 1.39% lower than the result of using MHE reference data.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.75-84
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• 2013

In this study, the patterns and characteristics according to gait cycle were analyzed using to EMG signals during walking, and analyzed in the time domain and frequency domain. The experiments was performed divide to level-ground walking and stair walking, and gait cycle was analysis by stance and swing. In the sagittal plane by using the tilt sensor measures the angle of the lower leg, and EMG was measured from the quadriceps and biceps femoris. The tilt of the lower leg was showed the biggest tilt at HS, and showed lowest value at TO. All in walking according to the gait cycle IEMG showed a specific pattern, and is expected useful to determine the gait cycle and kind. In the frequency domain analysis was using STFT on able to frequency analysis according to time, and using the tilt sensor was identify gait cycle. We analyzed also spectrum of the results of the STFT in all gait types, and recognized that stance had broad bandwidth than that of swing. Through this study, it was confirmed the possibility of judgment and analysis of the gait cycle using EMG and the tilt in the sagittal plane of the lower leg. When used it, can improve the quality of life of amputation patients