• 항공우주산업기술동향
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• 제8권2호
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• pp.39-45
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• 2010

질량이 크고 정밀한 정렬이 요구되는 전개형 영상 레이더를 장착하기 위해서는 일반적으로 위성을 수평상태로 놓고 조립을 수행하게 된다. 이는 전개형 안테나의 회전축을 중력축과 일치시키고 전개형 안테나를 중력방향과 반대로 질량을 보상함으로써 무중력 상태를 만들어 회전축에 무리한 힘을 가하지 않기 위함이다. 이러한 전개형 영상 레이더를 장착하기 위해서는 위성이 수평 상태로 놓이더라도 위성체 처짐이 없는 수직상태와 동일한 형상을 만들어 주어야 한다. 처짐이 발생한 위성체에 안테나를 장착하고 수직상태로 변경하면 처짐이 발생한 부분이 강제적으로 원상복귀하려는 힘으로 인해 안테나 정렬이 틀어질 수 있기 때문이다. 본 논문에서는 수평상태에서 위성의 처짐값을 확인하기 위한 방안을 찾고 처짐 보상을 위한 Reaction Force 값을 어떻게 구할 것인지를 보여주고 있다.

• 한국정밀공학회지
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• 제28권11호
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• pp.1323-1329
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• 2011

The purpose of study was to analyze how the visual information affects balance control of individuals during single leg stance. A total of 27 young normal people (20 males and 7 females, age: $13.7{\pm}2.6$, height: $162.3{\pm}13.2$ cm, weight: $53.9{\pm}13.9$ kg) was voluntarily involved in the experiment. The subjects were requested to maintain balance for 20 seconds with eyes both open and closed on a force plate and then foot ground reaction data were collected for that duration. Results showed that mean velocity of COP in closed eyes condition was larger 1.84 times than that of the open-eyes condition and range of vertical angle was increased approximately one degree in the closed eyes condition. To accomplish a balance, the frequency power in mediolateral and anteroposterior components of the foot-ground reaction force was increased by 1.3~1.4 times. Consequently, visual absence during single leg stance can result in critical loss of balance and lead to instability of body control.

• 한국동물위생학회지
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• 제46권2호
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• pp.175-179
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• 2023

This study was conducted to find out the compensation strategy through kinetic gait analysis by comparing dog with congenital luxation of the shoulder joint and normal dog. Ground reaction forces were recorded for all limbs while normal poodle dog and poodle dog with shoulder joint luxation was allowed to walk on an instrumented platform. The dogs were evaluated for maximal vertical force (MVF), body load distribution (BLD), and symmetry index (SI). The MVF was increased in the contralateral forelimb of luxated shoulder joint. The SI was also increased in a dog with dislocated shoulder joints in the forelimbs. For BLD, the maximum load distribution increased centrally, but the total load distribution decreased in the ipsilateral forelimb paw. In contrast, total load distribution was increased in the contralateral forelimb paw. During forelimb lameness, changes in weight-bearing load showed compensatory load redistribution. These biomechanical changes may lead to changes in the musculoskeletal system in a dog with luxated shoulder.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.733-740
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• 2016

To achieve bipedal walking in real human environments, a bipedal robot should be capable of modifiable walking both on uneven terrain with different heights and on flat terrain. In this paper, a novel walking pattern generator based on a 3-D linear inverted pendulum model (LIPM) is proposed to achieve this objective. By adopting a zero moment point (ZMP) variation scheme in real time, it is possible to change the center-of-mass (COM) position and the velocity of the 3-D LIPM throughout the single support phase. Consequently, the proposed method offers the ability to generate a modifiable pattern for walking on uneven terrain without the necessity for any extra footsteps to adjust the COM motion. In addition, a control strategy for bipedal walking on uneven terrain with unknown height is developed. The torques and ground reaction force are measured through force-sensing resisters (FSRs) on each foot and the foot of the robot is modeled as three virtual spring-damper models for the disturbance compensation. The methods for generating the foot and vertical COM of 3-D LIPM trajectories are proposed to achieve modifiable bipedal walking on uneven terrain without any information regarding the height of the terrain. The effectiveness of the proposed method is confirmed through dynamic simulations.

• 대한물리치료과학회지
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• 제9권3호
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• pp.97-106
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• 2002

Purpose. This study was tried to compare the effect of the change in postural deviation caused by the pain side Subjects and Methods. Inpatients and outpatients (n=71) were selected from I hospital who have a musculoskeletal low back pain and shoulder pain without any history of the central nervous system (CNS) lesions, orthopaedic problems of the both lower extremities, or the vestibular and the visual default. For the control group, normal and healthy subjects (n=30) were selected without any history of weight bearing disorders. the weight bearing was rated by the computerized force plate. Results. 1) Postural deviation was not significant difference between patients and control group(p<0.01). But postural deviation in patients was more pronounced than control group. 2) There was significant difference of postural deviation between in patients according to the pain side(p<0.01). When the pain side was on the left side, postural deviation tended to the right. When the pain side was on the right side and vertebral body, postural deviation tended to the left. 3) There was no significant difference of postural deviation between regional pain in shoulder and regional pain in low back(p<0.01). Discussions and Conclusion. As a result, the pain, for sure, affected the good posture and its keeping process directly or/and indirectly. Therefore, as the postural deviation increases, the additional energy consumption increased by the works of the muscles to keep the good posture. Preponderated postural deviation, furthermore, could load too much to the musculoskeletal system, leading to increase the pain. The postural deviation, a result of the pain, can cause a secondary deformity of the distal area as a compensatory reaction, and this compensation actually become a cause of the musculoskeletal symptom back in a cycle. Therefore, the appropriate treatment of the musculoskeletal problem and the education of the posture correction should be given to decrease the pain, preventing the secondary deformities, and increasing muscle energy efficiency of the posture remaining muscles.

• 대한기계학회논문집A
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• 제35권9호
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• pp.1071-1076
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• 2011

본 연구에서는 산업용 다관절 로봇을 이용한 3 차원 곡면가공 방안에 대하여 연구하였다. 가반중량이 큰 산업용 로봇의 경우 반복위치정밀도가 높지 않아 위치오차와 가공 깊이 방향 오차를 발생시키며, 본 연구에서는 레이저 변위센서를 이용하여 이를 보정하는 방법을 제시하였다. 로봇교시포인터의 수를 줄이기 위하여 가공면의 특이점들만을 이용하여 곡면 가공이 가능하도록 로봇 궤적을 생성하는 방안을 연구하였다. 본 연구에서는 실제 산업용 로봇을 이용하여 가공시험을 수행하였다. 회전수, 가공각도, 가공깊이, 가공속도 등의 가공조건을 변경해가며, 표면조도, 실제 가공깊이, 진동 및 소음 발생에 대한 시험을 수행하여 적용 가능한 가공조건을 도출하였다.