• 한국운동역학회지
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• 제19권1호
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• pp.27-36
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• 2009

본 연구에서는 수직점프시 몸통운동의 제약이 수직점프의 수행에 미치는 영향을 알아보기 위해 10명의 성인 남성을 대상으로 몸통을 자유롭게 사용한 일반적인 형태와 몸통동작을 제한한 형태의 수직점프를 비교, 분석하였다. 분석 결과 몸통동작을 제한한 경우 비 제약점프에 비해 10% 정도의 수행 손실이 있었는데, 이는 이지 순간의 중심 높이보다는 이 지속도의 차이에 의해 발생하였다. 몸통의 운동은 엉덩관절의 모멘트 파워를 증가시켜 추진의 초기 시점부터 지면반력의 증가에 기여하였는데 이러한 요인이 수행력 증가의 주요한 요인으로 작용하였다. 반면 몸통운동이 제한된 점프에서는 엉덩관절에서의 역학적 출력의 감소를 보상하는 측면에서 무릎관절의 역할이 증가하였으나 충분치 못하였다. 또한 몸통동작의 제한으로 엉덩관절 무릎관절 발목관절의 순차적인 신전패턴과는 상이하게 추진시점 직후 엉덩관절과 무릎관절이 동시에 신전하는 형태의 점프가 이루어져 협응패턴의 변화가 나타났다. 결국 본 연구의 결과 몸통의 적절한 사용은 수직점프의 수행 향상에 효과적으로 기여하는 것으로 나타났다.

• 산업기술연구
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• 제28권A호
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• pp.167-176
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• 2008

Recently, lots of studies are performed in developing of active orthosis. Exact and simple muscle force estimation is important in developing orthosis which assists muscle force for disabled people or physical laborers. Hill-type muscle model dynamics is common method for estimation of muscle forces. In Hill-type muscle model, we must know muscle length and moment arm which largely affect muscle force. And several methods are proposed to estimate muscle length and moment arm using joint angle. In this study, we compared estimation results of those method with data from body model of opensim to find which method is exact for estimation of muscle length and moment arm.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.130-138
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• 2000

The position of the automobile seat back is very important for the neck injury in the rear-end collisions. The effects of the position have been evaluated experimentally. A sled simulator is utilized with a velocity of 33 km/h. The position is varied by the angle of seat back from 25 to 65 degrees. All the configurations of the seat are fixed except the angle. The neck injuries are calculated by the equations accepted in the industries. Also, the sled tests with other velocities are carried out for the comparison study. Using the results of the test, the effects of seat back strength are discussed to minimize the occupant neck injury in rear end collisions.

• 한국소음진동공학회논문집
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• 제17권10호
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• pp.907-911
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• 2007

Compliance of joints must be considered when we analyze dynamics of a multi-body system. If the virtual model for CAE(computer aided engineering) analysis does not consider compliance, the result of CAE analysis can be very different from the actual experimental result. Especially in a biped walking robot, the robot may lose walking stability due to the compliance in joints of a walking robot. This paper proposed a method applying a compliance of joints in the biped walking robot to a virtual model. Also, through the 3-D displacement measurement using a laser tracker, it was demonstrated that the virtual model considering the joint compliance could effectively simulate the nonlinear motion of the real model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.939-940
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.1007-1008
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.879-880
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• 2008

• 한국운동역학회지
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• 제23권1호
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• pp.63-76
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• 2013

The purpose of this study was to investigate the effects of knee joint muscle fatigue and overweight on the angular displacement and moments of the lower limb joints during landing. Written informed consent forms, which were approved by the human subject research and review committee at Dong-A University, were provided to all subjects. The subjects who participated in this study were divided into 2 groups: a normal weight group and an overweight group, consisting of 15 young women each. The knee joint muscle fatigue during landing was found to increase the dynamic stability by minimizing the movements of the coronal and horizontal planes and maintaining a more neutral position to protect the knee. The effect of body weight during landing was better in the normal weight group than in the overweight group, with the lower limbs performing their shock-absorbing function in an efficient manner through increased sagittal movement. Therefore, accumulated fatigue of knee joint muscles or overweight may be highly correlated with the increase in the incidence of injury during landing after jumping, descending stairs, and downhill walking.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 추계학술대회 논문집
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• pp.235-240
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• 2005

관절형 컨테이너 크레인은 계류 시 Boom이 ㄱ자 형태인 크레인을 말한다. 즉, 계류 시 Inner Boom은 거의 수직이고, Outer Boom은 거의 수평이다. 이 크레인은 보통의 컨테이너 크레인과는 달리 주변 환경의 원인으로 인해 컨테이너 크레인의 고도가 제한될 경우에 사용된다. 관절형 컨테이너 크레인의 높이는 계류 시 70m에 달하기 때문에 바람에 매우 큰 영향을 받게 된다. 이에 따라 풍하중이 컨테이너 크레인에 미치는 영향에 대한 연구의 필요성이 증대되고 있다. 따라서 본 연구에서는 풍하중이 작용할 때, 풍하중의 작용 방향에 따라 컨테이너 크레인의 각 지지점에서 발생하는 반력 분포와 기계실의 위치변화가 관절형 컨테이너의 구조 안정성에 미치는 영향을 유한요소해석을 통해 분석하였다.

• 한국정밀공학회지
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• 제13권2호
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• pp.76-83
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• 1996

We have developed the unconventional robot arm which is composed of the two main parts, one is a ball screw and the other is a robot arm. The dynamic systems of the robot arm and ball screw are unstable systems coupled with each other. The ball screw mechanism is unstable system but controllable system. The robot arm's dynamics is quasi stable system when ball screw's angular position is zero, else, unstable system. Our system has the duality between stability and controllability at the view point of control. This duality causes difficulty to control of the robot arm using normal control law. We have investigated the location of the characteristic roots of the dynamic equation. And we have found out that the best condition for the control of the arm is quasi stable state. In this paper, we have proposed multiple control laws which are consist of three components to guarantee the stability and controllability simultaneously. The computer simulations were carried out based on VSC about the angular position control of the robot arm, and it is confirmed that the good performances could be obtained by using new controller.