• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1638-1641
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• 2004

Many walking stands, and assisting tools have been developed for the people with low-limb disability to prevent diseases from bedridden state and to help them walk again. But many of those equipments require user to have some physical strength or balancing ability. In our last research, we developed walking assist system for the people with lower-limb disability. With the system, user can be assisted by actuators, and do not have to worry about falling down. The system adapted the unique closed links structure with four servomotors, three PICs as controller, and four limit switches as HMI (human man interface). We confirmed the adaptability of the system by the experiment. In this research, Muscle Stiffness Sensor was tested as the advanced HMI for walking assist system, and confirmed the adaptability by the experiment. As Muscle Stiffness Sensor can attain the muscle activity, user can interface with any device he want to control. Experimental result with Muscle Stiffness sonsor showed that user could easily control the walking assist system as his will, just by changing his muscle strength.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2248-2253
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• 2005

Although the progress in bipedal walking is impressive in recent years, biped robots still require very high torque and can walk only for a short time interval with their internal batteries. Therefore, further research needs to be carried out to enhance walking efficiency of these robots. In order to achieve this goal, we attempt to imitate human walking with pelvis and waist joint rotations in the frontal plane. In order to investigate the effect of the pelvis and waist joint rotations in the frontal plane motion, we study the frontal plane model with a triangular structure made up of a waist joint and two hip joints. Through simulation, we show that the pelvis rotation can reduce the maximum torque and the control effort, and the waist joint rotation can reduce the trunk sway caused by the pelvis rotation. The combination of these two rotations makes the bipedal walking in the frontal plane more efficient.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.2
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• pp.53-60
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• 2018

PURPOSE: This study aimed to identify the effect of a backward walking exercise using a mirror on balance and gait in patients with stroke. METHODS: Twenty subjects with post-stroke hemiparesis volunteered to participate in this study. The experimental and control groups performed backward walking exercise plus conventional therapy or conventional physical therapy, respectively, for 6 weeks. Assessment instruments included the Berg Balance Scale (BBS), timed up and go test (TUG), and 10-m walking test (10MWT). Evaluation was performed before and after the 6-week training period. We conducted a paired t-test to compare the within-group changes before and after the intervention. An independent t-test was used to compare between-group differences. The statistical significance level was set at ${\alpha}=.05$ for all variables. RESULTS: The experimental group showed a significant within-group change in the BBS, TUG, and 10MWT (p<.05). The control group also showed a significant change (p<.05). A significant difference was observed between the experimental and control groups with regard to changes in the BBS, TUG, and 10MWT results after the interventions (p<.05). CONCLUSION: This study demonstrated that backward walking exercise using a mirror may be valuable for future research. Further studies with a wider range of pathology and longer experiment duration are required to validate the results of the present study.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.1
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• pp.1398-1405
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• 2018

The purpose of this study was to investigate the effect of heel off stairway walking exercise on the increase of muscle activity and balance activity of the ankle joint muscles in university students with functional ankle instability. The conservative treatment for the control group consisted of stairway walking (n=10) and the experimental group consisted of heel off stairway walking (n=11). The therapeutic intervention of the control and experimental groups was performed a total of 12 exercise sessions, 3 times per week for 4 weeks. To compare the two groups, the level of ankle disability was assessed by using the EMG, BT4 and Pedoscan in pre-treatment and post-treatment. Muscle activity increased in both the experimental groups and control groups in each group, however there was no significant difference between the groups. Balance ability did not show any significant difference. This study demonstrates that heel-off stairway walking is effective in significantly increasing muscle activity, however did not significantly improve balance ability.

• 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 the Korean Society of Physical Medicine
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• v.14 no.1
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• pp.35-41
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• 2019

PURPOSE: This study examined the effects of a vestibular stimulation training program on the walking ability of chronic stroke patients over a six month period. METHODS: Forty stroke patients were enrolled in this study. The patients were divided randomly into a control group (n=20) and experimental group (n=20). A general exercise program was applied to Group I and vestibular stimulation training was applied to Group II(30 min, three times a week for six weeks). The changes in straight walking ability, curved walking ability, and functional walking ability were measured using a 10 m walking test figure-of-eight-walking test, and dynamic gait index, respectively. The measures before and after the program were compared using a paired t-test for a comparison of each group and an independent t-test for a comparison between groups. RESULTS: The changes in each group were examined according to the measurement period. The Experimental group showed significant functional improvement in all three tests after the vestibular stimulation training program, but the control group did not show significant improvement in any of the tests after the general exercise program. A comparison of the changes between groups revealed the experimental group to show significantly higher improvement than the control group in all tests. CONCLUSION: The vestibular stimulation training program helps improve the gait function of stroke patients. Based on the results of this study, it is expected that various vestibular stimulation training programs will be developed and applied in a range of places.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1081-1087
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• 2006

Generally, biped walking is difficult to control because a biped robot is a nonlinear system with various uncertainties. In this paper, we propose a hybrid sliding-mode control method using a WNN uncertainty observer for stable walking of the 5-link biped robot with model uncertainties and the external disturbance. In our control system, the sliding mode control is used as main controller for the stable walking and a wavelet neural network(WNN) is used as an uncertainty observe. to estimate uncertainties of a biped robot model, and the error compensator is designed to compensate the reconstruction error of the WNN. The weights of WNN are trained by adaptation laws that are induced from the Lyapunov stability theorem. Finally, the effectiveness of the proposed control system is verified through computer simulations.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1495-1499
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• 2003

There is some equipment that helps user to exercise and to walk. But almost all equipments require some physical strength of their muscles. So we developed a system that could assist walking action of the people with lower-limb disability. The system called as walking stand adopted the balancing mechanism which assures the stable walking, and the 4 link-based mechanism that had 2 degrees of freedom on each leg. The walking stand uses four motors and has two sets of the special link-structure to simulate the human walking mechanism. With our system, even serious disabled with lower-limb disability may enjoy walking rehabilitation. And by adjusting the power, it can be used as the walking assistant mechanism instead of conventional wheelchairs. Experiments showed that our walking stand is applicable to the rehabilitation and also to the mobile device in our daily life for those people who do not have enough physical ability to walk by themselves.

• The Journal of Korea Robotics Society
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• v.1 no.2
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• pp.203-211
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• 2006

In this research, a comprehensive study is performed upon the design of a quadruped walking robot. In advance, the walking posture and skeletal configuration of the vertebrate are analyzed to understand quadrupedal locomotion, and the roles of limbs during walking are investigated. From these, it is known that the forelimbs just play the role of supporting their body and help vault forward, while most of the propulsive force is generated by hind limbs. In addition, with the study of the stances on walking and energy efficiency, design criteria and control method for a quadruped walking robot are derived. The proposed controller, though it is simple, provides a useful framework for controlling a quadruped walking robot. In particular, introduciton of a new rhythmic pattern generator relieves the heavy computational burden because it does not need any computation on kinematics. Finally, the proposed method is validated via dynamic simulations and implementing in a quadruped walking robot, called AiDIN(Artificial Digitigrade for Natural Environment).

• Journal of International Academy of Physical Therapy Research
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• v.10 no.4
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• pp.1873-1878
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• 2019

Background: Walking is a complex activity. The main components of walking include balance, coordination, and symmetrical posture. The characteristics of walking patterns of stroke patients include slow walking, measured by gait cycle and walking speed. This is an important factor that reflects post-stroke quality of life and walking ability. Objective: This study aimed to examine the effect of deep lumbar muscle stabilization exercise on the spatiotemporal walking ability of stroke patients. Design: Quasi-experial study Methods: The experiment was conducted 5 times per week for 4 weeks, with 30 minutes per session, on 10 subjects in the experimental group who performed the deep lumbar muscle stabilization exercise and 10 subjects in the control group who performed a regular exercise. Variables that represent the spatiotemporal walking ability (step length, stride length, step rate, and walking speed) were measured using GAITRrite before and after the experiment and were analyzed. Results: There was a significant difference in the pre- and post-exercise spatiotemporal walking ability between the two groups (p<.05). Furthermore, there was a significant difference in the step rate and walking speed between the two groups (p<.05). Conclusions: Deep lumbar muscle stabilization exercise is effective in improving the walking ability of stroke patients. Therefore, its application will help improve the spatiotemporal walking ability of stroke patients.