• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.490-496
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• 1995

A four-legged mobile robot can move on the plain terrain with mobility and stability, but if there exist any obstacles on the terrain of the motion direction, it takes extra times for a mobile robot to cross those obstacles and the stability should be considered during motion. The main objevtive is the study of a quadruped which can cross obstacles with better mobility, stability and fuel economy than any other wheeled or tracked vehicles. Vertical step, isolated wall and ditch are the basic obstacles and by understanding those three cases perfectly, a quadruped can move on any mixed rough terrain as 4-legged animal moves. Each leg of a determine the crossing capability in a static analysis. A quadruped can be simplified with links and joints. By applying the research method, a quadruped can determine the control procedures as soon as it receives the terrain informations from scanner and finally can be moved as animals move with mobility and stability.

• Physical Therapy Korea
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• v.3 no.1
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• pp.1-11
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• 1996

The purpose of this study was to analyse the subtalar joint movement characteristics in human stance phase. The data of subtalar joint movement patterns are collected by CTA(calcaneus to tibia angle) measurements. CTA is defined as a angle formed between the bisect of the posterior shank and bisect of the posterior heel, as determined by placement of the retroreflective markers. The angle measured in degrees. The participants are 74 healthy individuals (37 men and 37 women) who have no orthopedic and neurological impairment, aged from 19 to 29 years(mean 22.95). Prior to participation, each subjecct informed the procedures of experiment from researcher and assistant researcher. The equipments of this study are walking grid, marking tapes, goniometer, video camera, monitor and ink for foot print are used in the study. In order to determine the statistical significance of result, the paired t-test and Pearson correlation were applied at the 0.05 level of significance. The results were as follows : 1. The reliability of measured CTA value are showed a high correlation, ranged from .86 - .94. 2. The mean value of step width are 7.67cm in men and 6cm in women. So, significant difference between men and women in 0.05 level of significance. 3. There was significant difference between man and women's TOA(toe out angle)(p<0.05). 4. The CTA of female's is more higher than male's one, however not statistical difference between man and women(p>0.05). 5. The CTA is reduced according to increasing TOA(p<0.05).

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.9
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• pp.926-934
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• 2006

This paper proposes intelligent control of a virtual walking machine that can generate infinite floor for various surfaces and can provide proprioceptive feedback of walking to a user. This machine allows users to participate in a life-like walking experience in virtual environments with various terrains. The controller of the machine is implemented hierarchically, at low-level for robust actuator control, at mid-level fur platform control to compensate the external forces by foot contact, and at high-level control for generating walking trajectory. The high level controller is suggested to generate continuous walking on an infinite floor for various terrains. For the high level control, each independent platform follows a man foot during the swing phase, while the other platform moves back during single stance phase. During double limb support, two platforms manipulate neutral positions to compensate the offset errors generated by velocity changes. This control can, therefore, satisfy natural walking conditions in any direction. Transition phase between the swing and the stance phases is detected by using simple switch sensor system, while human foot motions are sensed by careful calibration with a magnetic motion tracker attached to the shoe. Experimental results of walking simulations at level ground, slope, and stairs, show that with the proposed machine, a general person can walk naturally on various terrains with safety and without any considerable disturbances. This interface can be applied to various areas such as VR navigations, rehabilitation, and gait analysis.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.3
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• pp.89-97
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• 2021

PURPOSE: This study examined the effects of coordinative locomotor training on the spine appearance and quality of life of patients with idiopathic scoliosis. METHODS: This study included two patients with idiopathic scoliosis: one with a thoracic and lumbar type scoliosis and the other with thoracic type scoliosis. The study design was a single case study (A-B-A'), with a baseline-intervention/phase-post-intervention. The baseline (A) was designed and measured five times, intervention phase (B) ten times, and post-intervention (A') five times. The coordinative locomotor training program was divided into 10 minutes of warm-up exercise, 30 minutes of the main exercise, and 10 minutes of the finishing exercise, for 50 minutes each time. The primary outcome measurements were measured using the Cobb's angle, Adam's test, and Gait view pro 2.0 to determine the changes in the spine appearance. The secondary outcome measurements were compared before and after using the SRS-22 questionnaire to determine the quality of life of the scoliosis patients. A statistical test analyzed the mean and standard deviation, and the rate of change was presented by a visual analysis method using descriptive statistics and graphs. RESULTS: The findings showed that the spine appearance and quality of life of the two subjects were improved compared to the baseline measurements during the intervention phase, and the improved state was maintained during the post-intervention period. CONCLUSION: These findings indicate that coordinative locomotor training may help improve the spine appearance and quality of life of patients with idiopathic scoliosis.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.17-23
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• 2022

Objective: The aim of this study was to investigate the effect Tiger-step walking on the movement of the lower extremities during walking. Method: Twenty healthy male adults who had no experience of musculoskeletal injuries on lower extremities in the last six months (age: 26.85 ± 3.28 yrs, height: 174.6 ± 3.72 cm, weight: 73.65 ± 7.48 kg) participated in this study. In this study, 7-segments whole-body model (pelvis, both side of thigh, shank and foot) was used and 29 reflective markers and cluster were attached to the body to identify the segments during the gait. A 3-dimensional motion analysis with 8 infrared cameras and 7 channeled EMG was performed to find the effect of tigerstep on uphill walking. To verify the tigerstep effect, a one-way ANOVA with a repeated measure was used and the statistical significance level was set at α=.05. Results: Firstly, Both Tiger-steps showed a significant increase in stance time and stride length compared with normal walking (p<.05), while both Tiger-steps shown significantly reduced cadence compared to normal walking (p<.05). Secondly, both Tiger-steps revealed significantly increased in hip and ankle joint range of motion compared with normal walking at all planes (p<.05). On the other hand, both Tiger-steps showed significantly increased knee joint range of motion compared with normal walking at the frontal and transverse planes (p<.05). Lastly, Gluteus maximus, biceps femoris, medial gastrocnemius, tibialis anterior of both tiger-step revealed significantly increased muscle activation compared with normal walking in gait cycle and stance phase (p<.05). On the other hand, in swing phase, the muscle activity of the vastus medialis, biceps femoris, tibialis anterior of both tiger-step significantly increased compared with those of normal walking (p <.05). Conclusion: As a result of this study, Tiger step revealed increased in 3d range of motion of lower extremity joints as well as the muscle activities associated with range of motion. These findings were evaluated as an increase in stride length, which is essential for efficient walking. Therefore, the finding of this study prove the effectiveness of the tiger step when walking uphill, and it is thought that it will help develop a more efficient tiger step in the future, which has not been scientifically proven.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.393-399
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• 2015

Objective : This study was conducted with an aim to use it as basic data for developing assistive devices, such as insoles that can suppress the progress of degenerative diseases and strategies, to improve early degenerative diseases by assessing walking characteristics of farm workers who were classified as KL-grade in the perspective of motor mechanics. Method : 38 male and female adults who complained of knee joint pain for more than six months were selected, and they were classified according to KL-grade. KL-grade was assessed by an orthopaedic specialist and an occupational environment health specialist. Filming equipment (FX-1, CASIO, Japan) and a ground reaction force system (AMTI OR6, AMTI, USA) were used to identify ground reaction force characteristics, and WOMAC was used for a pain rating scale. Results : There was a difference between the right and left side (axis-X) according to KL-grade, and when the grade was higher, the internal ground reaction force was also higher. Changes in COP were not affected by KL-grade of the knee joint, but it tended to increase as the grade increased. There were differences in the time required for limb support while walking according to the grades, and when the grade was higher, walking was more inefficient with long braking force and short propulsion forces. Also, pain rating scale, the right and left side, and COP changes while in support phase were related. Conclusion : There was a partial, statically significant difference in KL-grade and ground reaction force occurring during the support phase, and there were differences in ground reaction forces according to the grades of degenerative arthritis in the knee joint, indicating that this study is worthy as basic data for future studies.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.317-325
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• 2011

This study aims to develop the stance-control typed 4-bar linkage orthotic knee joint that replace the locked orthotic knee joint for the disabled with poliomyelitis and muscle weakness of lower limb. Unlike the existing stance-control orthotic knee joint, there are no needs of electric power, connecting circuit, bulky compomnets, etc, because this 4-bar linkage orthotic knee joint is controled by geometric locking. To evaluate the 4-bar linkage orthotic knee joint, a subject participated in this study who has been diagnosed with lower limb poliomyelitis and have used locked type orthotic knee joint. In the results of analysis of subject's gait using 3-dimentional motion analysis system, this 4-bar linkage orthotic knee joint provide the stability during stance phase and knee flexion during swing phase.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.319-341
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• 2016

Objective:This research analyzed the lower-limb motion in kinetic and kinematic way while walking on various terrains to develop Foot-Ground Contact Detection (FGCD) algorithm using the Inertial Measurement Unit (IMU). Background: To estimate the location of human in GPS-denied environments, it is well known that the lower-limb kinematics based on IMU sensors, and pressure insoles are very useful. IMU is mainly used to solve the lower-limb kinematics, and pressure insole are mainly used to detect the foot-ground contacts in stance phase. However, the use of multiple sensors are not desirable in most cases. Therefore, only IMU based FGCD can be an efficient method. Method: Orientation and acceleration of lower-limb of 10 participants were measured using IMU while walking on flat ground, ascending and descending slope and stairs. And the inertial information showing significant changes at the Heel strike (HS), Full contact (FC), Heel off (HO) and Toe off (TO) was analyzed. Results: The results confirm that pitch angle, rate of pitch angle of foot and shank, and acceleration in x, z directions of the foot are useful in detecting the four different contacts in five different walking terrain. Conclusion: IMU based FGCD Algorithm considering all walking terrain possible in daily life was successfully developed based on all IMU output signals showing significant changes at the four steps of stance phase. Application: The information of the contact between foot and ground can be used for solving lower-limb kinematics to estimating an individual's location and walking speed.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.257-263
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• 2015

Objective : The purpose of this study was to investigate the effect of genu valgum on the body mass index, movement of lower limb joints, and ground reaction force. Methods : Gait patterns of 30 college students with genu valgum were analyzed and the static Q angle of the femur was measured for selecting genu valgum of the subjects. To analyze the kinetic changes during walking, the six-camera Vicon MX motion analysis system was used. The subjects were asked to walk 12 meters using the more comfortable walking method for walking. After they walked 12 meters more than 10 times, their most natural walking patterns were chosen three times and analyzed. Results : As a result of measuring a relationship between genu valgum and Q-angle, as the Q-angle increases, it showed a genu valgum also increased. Body Mass Index showed a significant difference between the groups was higher in the genu valgum group.(p<.001). The analysis result showed that genu valgum had a significant effect on the internal rotation moment in the hip joint(p<.05). Also, genu valgum had a significant effect on the internal rotation moment of the knee joint(p<.05). The comparative analysis of the Medial-Lateral ground reaction force in the genu valgum group showed a tendency to increase the medial ground reaction force(p<.05). The vertical ground reaction forces of the middle of the stance phase(Fz0) showed a significant increase in genu valgum group(p<.05), in particular the results showed a decrease in the early stance phase(p<.001). Conclusion : In conclusion, the change in body mass is considered to be made by proactive regular exercise for improvement of the genu valgum. In addition, the prevention of the deformation caused by secondary of the genu valgum in this study may be used as an indicator of the position alignment rehabilitation for structural and functional improvements. Applying a therapeutic exercise program for the next lap will require changes in posture alignment.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.1
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• pp.36-43
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• 2007

Purpose: An objective analysis and observations were to be done on hemiplegia patients that are wearing a walking support device, Stroke shoes. Their improvements in walking pace, the reduction of distance between the two knee joint, the increase of curve angle of the knee joint and their steps and the reduction of ankle joint upon swing phase were analyzed using a 20 walking analyzer. Methods: An examination was carried out to see the patients' communication skill and independent walking and then let them walk with the Stroke shoes on to get results before and after wearing it. Simi Reality Motion Systems GmbH (Germany, 2007) was used to analyze the results regarding knee joint and ankle joint angle changes of sagitta plane and coronal plane, stepping distances, distances between the knees and walking pace. Results: 1. The articulation angle of ankle joint during swing phase decreased and knee joint has shown a statistically significant increase in such value(p<0.05). 2. Only knee joint showed a significant increase in articulation angle during heel strike(p<0.05). 3. Knee joint showed a significant increase in articulation angle during toe off(p<0.05). 4. The distance between the two knees as well as their foot steps significantly decreased compared with when Stroke shoes were not worn(p<0.05). 5. Stroke shoes with FES have shown positive effects on the patients in improving their walking styles overall. (p<0.05). Conclusion: There was an improvement in rotation walking pattern by a reduction in the distance between the knees after wearing Stroke shoes with FES. Plantar flexion reduced that occurred in ankle joint during walking and flexion angle increased in knee joint, both of which improved foot drop which was a major problem in hemiplegia patients. Also it is believed that the device will have some positive influences on knee joint stiffening paralysis to aid in improving inefficient walking phases.