• 한국운동역학회지
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• 제14권3호
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• pp.17-35
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• 2004

The purpose of this study is to explain developmental process of gait via angle-angle diagram to understand how coordinated relationships and control change with age. Twenty four female children, from one to five years of age were the test subjects for this study, and their results were compared to a control group consisting of twenty one adult females. The Vicon 370 CCD camera, VCR, video timer, monitor, and audio visual mixer was utilized to graph the gait cycle for all test subjects. Both coordinated Intra-limb relationships, and range of motion and timing according to quadrant were explained through the angle angle diagram. Movement in the sagittal plane showed both coordinated relationships and control earlier than movement in the coronal or transverse plane. In the sagittal plane, hip and Knee coordinated relationships developed first (from one year of age.) Coordinated relationships in the Knee and ankle and hip and ankle developed next, respectively. Both hip and ankle and knee and ankle development were inhibited by the inability of children to completely perform plantar flexion during the swing and initial double limb support phases. Children appeared to compensate for this by extending at their hip joint more than adults during the third phase, final double limb support. In many cases the angle angle diagram for children had a similar shape as adult's angle angle diagram. This shows that children can coordinate their movements at an early age. However, the magnitudes and timing of children's angle angle diagrams still varied greatly from adults, even at five years of age. This indicates that even at this age, children still do not possess full control of their movements.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.215-219
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• 2003

In this paper, we generate a trajectory minimized the energy gait of a biped robot for walking a staircase using genetic algorithms and apply to the computed torque controller for the stable dynamic biped locomotion. In the saggital plane, a 6 degree of freedom biped robot that model consists of seven links is used. In order to minimize the total energy efficiency, the Real-Coded Genetic Algorithm (RCGA) is used. Operators of genetic algorithms are composed of a reproduction, crossover and mutation. In order to approximate the walking gait, the each joint angle is defined as a 4-th order polynomial of which coefficients are chromosomes. Constraints are divided into equality and inequality. Firstly, equality constraints consist of position conditions at the end of stride period and each joint angle and angular velocity condition for periodic walking. On the other hand, inequality constraints include the knee joint conditions, the zero moment point conditions for the x-direction and the tip conditions of swing leg during the period of a stride for walking a staircase.

• 재활복지공학회논문지
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• 제7권2호
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• pp.75-84
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• 2013

본 연구에서는 근전도 신호를 이용하여 보행주기에 따른 패턴 및 특징을 시간영역과 주파수영역으로 나누어 분석하였다. 보행주기를 입각기와 유각기로 나누어 평지보행과 계단보행 실험을 실시하여 그 결과를 분석하였으며, 이때 시상면에서의 하퇴부 각도와 대퇴사두근과 대퇴이두근의 근전도 신호를 대상으로 하였다. 하퇴부의 기울기는 모든 보행에서 HS일 때 가장 큰 기울기 값을 나타내었으며, TO일 때 가장 낮은 값을 나타내었다. 시간영역에서의 근전도 분석은 모든 보행에서 보행주기에 따라 IEMG가 일정한 패턴을 보였으며, 보행 종류 및 주기 판단에 가장 용이할 것으로 판단된다. 주파수영역에서의 분석은 시간에 따른 주파수 분석이 가능한 STFT법을 사용하였으며, 기울기센서를 이용하여 보행주기를 구분하고자 하였다. 또한 STFT한 결과를 스펙트럼으로 나타내어 분석하였으며, 모든 보행에서 입각기가 유각기보다 더 높은 주파수를 가지는 것을 확인하였다. 본 연구를 통하여 근전도와 시상면에서의 하퇴부 기울기를 이용하여 보행주기 판단 및 분석의 가능성을 확인하였으며, 이를 활용하면 하지 절단환자의 보행의지를 판단하여 의족제어 및 효율적 재활에 기여할 수 있을 것으로 판단된다.

• 정보처리학회논문지B
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• 제13B권2호
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• pp.187-196
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• 2006

대부분의 3차원 캐릭터 애니메이션에서는 모션 캡쳐 장비를 통해서 포착된 동작 데이터를 이용하여 다양한 지형상에서 캐릭터의 이동 동작을 표현한다. 이러한 동작 포착 데이터는 실제 사람과 같이 움직이는 동작들을 자연스럽게 표현할 수 있으나, 만약 다양한 지형에 대해 움직이는 동작을 표현할 경우, 지형의 유형에 따라 모든 동작을 캡쳐하여야 하고, 얻어진 동작 데이터를 다른 유형의 캐릭터에 적용할 경우 동작 데이터를 다시 얻거나 기존 동작 데이터를 재편집해야 하는 어려움이 있다. 따라서 본 연구에서는 평지면, 경사면, 계단면 그리고 굴곡면 등 다양한 지형에서의 적응적인 걷기, 달리기의 이동 동작을 생성하기 위한 통합적 생성 방법을 제안한다. 이 방법에서는 캐릭터의 신장이나 걷는 속도 걸음폭 등의 적은 매개변수들을 사용하여 이동 동작을 생성할 수 있다. 관절들의 위치나 각도는 역운동학(Inverse Kinematics)방법으로 계산하고, 골반과 이동하는 다리의 움직임 궤적 산출은 큐빅 스플라인 곡선을 활용한다. 또한 제안된 방법을 통해서 다양한 실제 캐릭터에 적용하여 이동 동작을 확인한다.

• 디자인학연구
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• 제17권4호
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• pp.141-148
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• 2004

본 논문은 스텝 애니메이션에서 표현되어지는 감성을 정의하고, 스텝 관련 감성 자극 요소들을 추출 측정, 분석하여 스텝의 직관적인 감성 표현을 정량화시키는 것을 목적으로 하고 있다. 실험 방법으로는 스텝 관련 27개의 감성 표현 어휘와 36개의 샘플 스텝 동영상의 상관관계를 설문 조사하였다. 통합된 데이터를 수량화 이론 III류를 이용하여 스텝의 감성적 멘털구조를 2차원 평면화 하였다. 이를 분석한 결과, 감성 스텝은 가로의 자신감 축과 세로의 안정감 축으로 형성되어 있음을 밝혀내었다. 감성 스텝의 2차원 분포도를 분석한 결과, <자신감, 불안감 쪽> 2사분면과 <자신감, 안정감 쪽> 3사분면은 데이터가 풍부한 반면 <소심함, 불안감 쪽> 1사분면과 <소심함, 안정감 쪽> 4사분면의 데이터 분포가 희박함을 보여주었다. 이러한 그래프 분석을 통해 불안감이 느껴지면서 소심한 감성과 안정감이 느껴지는 소심한 캐릭터의 감성은 스텝만으로 표현하기에는 난해한 감성 표현임을 파악할 수 있었다. 감성에 영향을 미치는 스텝의 신체 물리적 요소로는 <스텝의 간격> <스텝의 속도> <골반(Y축)의 움직임 각도> <팔 스윙 폭> <척추(x축)의 움직임 각도> <신체의 기울기> 6가지로 선정하여 분석하였다. 그 결과 <스텝의 속도>와 <신체의 기울기>가 스텝의 감성 자극에 가장 큰 영향을 미치는 요소임을 밝혀낼 수 있었다. 본 연구를 통해 캐릭터의 미묘한 감성 상태를 스텝 애니메이션에 자연스럽게 표현해 내는 과정에 있어 애니메이터들의 주관적인 가성 표현들을 객관화, 정량화시키고자 하였으며 향후 이 데이터들을 활용한 멀티컨텐츠의 적용을 목표로 하고 있다.

• 제어로봇시스템학회논문지
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• 제7권11호
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• pp.904-911
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• 2001

A broomstick swinging biped acrobatic controller is designed and simulated to show capability of the system of controllers: virtual model controller is employed for the robot\`s posture balancing control while a higher level fuzzy controller modulate the one of the virtual model controller\`s parameter for the pendulum swinging motion generation. The robot is of 7 degree-of-freedom, 8-link planar bipedal robot having two slim legs and a body. Each leg consists of a hip joint, a knee joint, an ankle joint and the body has a free joint at the top in the head at which a freely rotating broomstick is attached. We assume that the goal for the acrobat robot is to maintain a body balance in the sagittal plane while swinging up the freely up the freely rotating pendulum. We also assume that the actuators in the joints are all ideal torque generators. The proposed system of controllers satisfies the goal and the simulation results are presented.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1014-1022
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• 2009

A biped robot in locomotion can be regarded to be kinetically redundant in that the link-chain from its foot on the ground to its swing foot has more degrees of freedom that needed to realize stable bipedal locomotion. This paper proposes a new method to generate a trajectory for bipedal locomotion based on this redundancy, which directly generates a locomotion trajectory at the joint level unlike some other methods such as LIPM (linear inverted-pendulum mode) and GCIPM (gravity-compensated inverted-pendulum mode), each of which generates a trajectory of the center of gravity or the hip link under the assumption of the dominance of the hip-link inertia before generating the trajectory of the whole links at the joint level. For the stability of the trajectory generated in the proposed method, a stability condition based on the ZMP (zero-moment point) is used as a constraint as well as other kinetic constraints for bipedal motions. A 6-DOF biped robot is used to show how a stable locomotion trajectory can be generated in the sagittal plane by the proposed method and to demonstrate the feasibility of the proposed method.

• 한국정밀공학회지
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• 제23권4호
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• pp.75-82
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• 2006

In this paper, we propose an optimal trajectory for biped robots to move up-and-down stairs using a genetic algorithm and a computed-torque control for biped robots to be dynamically stable. First, a Real-Coded Genetic Algorithm (RCGA) which of operators are composed of reproduction, crossover and mutation is used to minimize the total energy. Constraints are divided into equalities and inequalities: Equality constraints consist of a position condition at the start and end of a step period and repeatability conditions related to each joint angle and angular velocity. Inequality constraints include collision avoidance conditions of a swing leg at the face and edge of a stair, knee joint conditions with respect to the avoidance of the kinematic singularity, and the zero moment point condition with respect to the stability into the going direction. In order to approximate a gait, each joint angle trajectory is defined as a 4-th order polynomial of which coefficients are chromosomes. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot that consists of seven links in the sagittal plane. The trajectory is more efficient than that generated by the modified GCIPM. And various trajectories generated by the proposed GA method are analyzed in a viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.612-620
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• 2006

This paper proposes an optimal trajectory generation method for biped robots for walking up-and-down stairs using a Real-Coded Genetic Algorithm (RCGA). The RCGA is most effective in minimizing the total consumption energy of a multi-dof biped robot. Each joint angle trajectory is defined as a 4-th order polynomial of which the coefficients are chromosomes or design variables to approximate the walking gait. Constraints are divided into equalities and inequalities. First, equality constraints consist of initial conditions and repeatability conditions with respect to each joint angle and angular velocity at the start and end of a stride period. Next, inequality constraints include collision prevention conditions of a swing leg, singular prevention conditions, and stability conditions. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot model that consists of seven links in the sagittal plane. The optimal trajectory is more efficient than that generated by the Modified Gravity-Compensated Inverted Pendulum Mode (MGCIPM). And various trajectories generated by the proposed GA method are analyzed from the viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.

• 대한물리치료과학회지
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• 제10권1호
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• pp.90-101
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• 2003

Gait analysis can provide a better understanding of how the alignment of the lower limb and foot can contribute to force observed at the knee. Anatomic and mechanical factors that affect loading in the knee pint can contribute to pathologic change seen at the knee in degenerative pint disease and should be considered in treatment plan. The purpose of this study is to present the gait analysis data and to determine whether there is any relationships between alignment of the lower limb, foot progression angle and knee pint moments in elderly healthy women with 3-dimensional motion analyzer. The results were as follows; 1. Cadence showed 114.8 steps/min, gait speed showed 1.05 m/s, time per a stride showed 1.06 sec, time per a step showed 0.53 sec, single-supporting phase was 0.41 sec, double-supporting phase was 0.24 sec, stride length was 1.04 m, Step length was 0.56 m. 2. According to the parameters of kinematics, the maximal knee flexion angle through swing phase showed left $46.82^{\circ}$, right $40.19^{\circ}$ and the maximal knee extension angle showed left $-1.32^{\circ}$, right $2.01^{\circ}$. knee varus showed left $26.90^{\circ}$, right $30.93^{\circ}$. 3. Moment, one of kinetic parameters of knee pint the maximal flexion moment showed left 0.363. Nm/kg, right 0.464 Nm/kg and maximal extension moment showed left 0.389 Nm/kg, right 0.463 Nm/kg. The maximal. adduction moment showed left 0.332 Nm/kg, right 0.379 Nm/kg and the maximal internal rotatory moment showed left 0.13 Nm/kg, right 0.140 Nm/kg. 4. On sagittal plane, the maximal power of knee joint showed left 0.571 J/kg, right 0.629 J/kg. On coronal plane, the maximal power of knee joint showed left 0.11 J/kg, right 0.12 J/kg. On transverse plane, the maximal power of knee joint showed left 0.058 J/kg, right 0.072 J/kg. 5. The subject who had varus alignment of the lower extremity had statistically higher in knee adduction moment in mid stance phase. 6. The subject who had large foot progression angle had statistically lower in knee adduction moment in late stance phase. A relationship was observed between the alignment of the lower extremity and the adduction moment of the knee joint during stance phase. Hence, we need some research to figure, out the change of adduction moment according to the sort of knee joint osteoarthritis and the normal geriatrics as well. And we also require more effective, specific therapeutic program by making use of those background of researches.