• Korean Journal of Applied Biomechanics
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• v.26 no.3
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• pp.303-308
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• 2016

Objective: This study evaluated the vertical and horizontal forces in the frontal plane acting on a pedal due to the vertical alignment of the lower limbs. Method: Seven male subjects (age: $25.3{\pm} 0.8years$, height: $175.4{\pm}4.7cm$, weight: $74.7{\pm}14.2kg$, foot size: $262.9{\pm}7.6mm$) participated in two 2-minute cycle pedaling tests, with the same load and cadence (60 revolutions per minute) across all subjects. The subject's saddle height was determined by the height when the knee was at $25^{\circ}$ flexion when the pedal crank was at the 6 o'clock position (knee angle method). The horizontal force acting on the pedal, vertical force acting on the pedal in the frontal plane, ratio of the two forces, and knee range of motion in the frontal plane were calculated for four pedaling phases (phase 1: $330{\sim}30^{\circ}$, phase 2: $30{\sim}150^{\circ}$, phase 3: $150{\sim}210^{\circ}$, phase 4: $210{\sim}330^{\circ}$) and the complete pedaling cycle. Results: The range of motion of the knee in the frontal plane was decreased, and the ratio of vertical force to horizontal force and overall pedal force in the complete cycle were increased after vertical alignment. Conclusion: The ratio of vertical force to horizontal force in the frontal plane may be used as an injury prevention index of the lower limb.

• Structural Engineering and Mechanics
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• v.16 no.5
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• pp.519-531
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• 2003

Piezoelectric actuators have long been recognised for use in aerospace structures for control of structural shape. This paper looks at active control of the swept shock wave/turbulent boundary layer interaction using smart flap actuators. The actuators are manufactured by bonding piezoelectric material to an inert substrate to control the bleed/suction rate through a plenum chamber. The cavity provides communication of signals across the shock, allowing rapid thickening of the boundary layer approaching the shock, which splits into a series of weaker shocks forming a lambda shock foot, reducing wave drag. Active control allows optimum control of the interaction, as it would be capable of positioning the control region around the original shock position and unimorph tip deflection, hence mass transfer rates. The actuators are modelled using classical composite material mechanics theory, as well as a finite element-modelling program (ANSYS 5.7).

• Journal of the Korean Society for Precision Engineering
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• v.25 no.7
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• pp.79-86
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• 2008

This paper describes the development of wearing intelligent shoe system to measure applied forces and moments (ground reaction forces and moments) on the soles of feet during human walking. In order to walk safely, robot must get the intelligent feet with 6-axis force/moment sensors (Fx sensor (x-direction force sensor), Fy sensor, Fz sensor, Mx sensor (Mx : x-direction moment sensor), My sensor, and Mz sensor) and detect the forces and moments data from the sensors. And the feet must be controlled with the data and controllers. While a human is walking, the forces and moments should be measured and analyzed for robot's intelligent feet. Therefore, the wearing intelligent shoe system should be developed. In this paper, four 6-axis farce/moment sensors and two high speed measuring devices were designed and fabricated, and the wearing intelligent shoe system was made using these. The characteristic tests of the wearing intelligent shoe system were performed, and the forces and moments were detected using it.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.536-539
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• 1997

This paper presents a three dimensional modeling and a trajectory generation for minimized impact walking of the biped robot. Inverse dynamic analysis and forward dynamic analysis are performed considering impact force between the foot and ground for determining the actuator capacity and for simulating the proposed biped walking robot. Double support phase walking is considered for close to human's with adding the kinematic constraints on the one of the single support phase.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1791-1792
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• 2008

휴머노이드 로봇은 기구적으로 불안정성을 내포하고 있기 때문에 이것에 대한 안정화를 하기 위해서 연구자들은 많은 방법을 사용하고 있다. 본 연구자는 실험 계획법(Design of Experiments)을 통해 본 연구자가 개발한 ISHURO-II의 발의 설계를 변경하였다. 퍼지 알고리즘을 이용하여 아랫부분에 장착된 FSR(Force Sensing Resistor)센서에서 ZMP(Zero Moment Point)의 값을 비교하여 더욱 안정된 보행이 가능하도록 하였다. 적용된 안정화 알고리즘의 성능은 VC++ 및 동역학 해석 프로그램을 이용한 시뮬레이션을 통해 검증하였다.

• Journal of Industrial Technology
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• v.11
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• pp.65-72
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• 1991

In this paper, a control algorithm is discussed when the quadruped walking robot walks over the unknown soft ground. Firstly, it estimated the relationship between the foot force and the ground sinkage at the leg-placing phase. Secondly, the generated soil property is applied to the leg-supporting phase. If the attitude angle is changed by incorrect ground sinkage compensation, the control algorithm adjusts the attitude angle using simplified orientation orientation matrix.

• Journal of the Korean Applied Science and Technology
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• v.37 no.2
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• pp.232-240
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• 2020

The purpose of this study was to analyze the effect of using standing step condition on biomechanical variables during jab in boxing. For this purpose, eight orthodox type college boxers(age = 20.38±0.52 yrs, height = 172.38±5.80 cm, body mass = 63.45±8.56 kg, career = 6.00±1.07 yrs) who without injury to the musculoskeletal system participated in the experiment over the last year. In order to verify the effect of biomechanical variables using standing step during jab in boxing, the paired t-test (α = .05) statistical method was used. First, W.S(with-step) showed a greater impact force than N.S(non-step), and muscle activity was analyzed to be low. Second, it was analyzed that the pelvis and foot segments move faster because W.S affects the velocity of the anterior segment of the human body. Third, the rotational movement of the pelvis was faster in W.S. Fourth, W.S was analyzed to have greater ground reaction force in the anterior caused by the right and left foot than N.S. Through this, it was found that the use of the standing step during jab increases the ground reaction force the velocity and rotational movement of the human segment. Therefore, it was confirmed that it allowed a faster and more agile movement, and thus produces a greater impact force with relatively less muscle activity. Therefore, in order to effectively deliver a greater impact force to the opponent during the jab, it was effectively analyzed to accompany the standing step.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.447-454
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• 2011

Purpose : The purpose of this study was to identify the effects of circuit class training on the performance of locomotor tasks in chronic stroke. Methods : The study included 45 patients with chronic stroke randomly divided into experimetal group and control group. Both groups participated in exercise classes three times a week for 8weeks. The experimental group had 10 workstation of circuit class designed to improve walking. The control group practiced fitness exercises by equipment in health center. Walking performance was assessed by measuring walking speed(timed 10-meter walk and TUG), GAITRite analysis and peak vertical ground reaction force through the affected foot during walking. Results : The experimental group demonstrated significant improvement(p<.05) compared with the control group in 10-meter walking and vertical ground reaction force after training. The experimental group showed significant improvements in the walking velocity and cadence by GAITRite system(p<.05). Conclusion : Task- oriented circuit class training leads to improvements in locomotor function in chronic stroke. Further studies are necessary to occur in usual environments to improve walking performance.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2271-2274
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• 2005

The desired ZMP is different from the actual ZMP of a humanoid robot during actual walking and stand upright. A humanoid robot must maintain its stable posture although external force is given to the robot. A humanoid robot can know its stability with ZMP. Actual ZMP may be moved out of the foot-print polygons by external disturbance or uneven ground surfaces. If the position of ZMP moves out of stable region, the stability can not be guaranteed. Therefore, The control of the ZMP is necessary. In this paper, ZMP control algorithm is proposed. Herein, the ZMP control uses difference between desired ZMP and actual ZMP. The proposed algorithm gives reaction moment with ankle joint when external force is supplied. 3D simulator shows motion of a humanoid robot and calculated data.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.2
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• pp.39-50
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• 1991

The movement of human beings - walking, running, jumping and climbing, etc. - have long been of scientific interest. In particular, the science of human walking is called gait analysis. Various instruments have been developed to assist in the study of human gait. Recently gait analysis techniques are used in medical research to investigate the abnormalities of pathological gait. In this study, we constructed a comprehensive gait analysis system consisting of a walkway, a force platform, foot-switches and an ExpertVision motion analysis system. Time-distance gait parameters and vector diagrams can be analyzed by a special application program called Force Analysis System(FOANAS). Using quantitative discrimination of this system, the gait characteristic parameters of normal and pathological gait is facilitated.