• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 춘계학술대회논문집
• /
• pp.313-318
• /
• 2003

The vibration of washing machine at spinning cycle is important problem that affects the performance of a product. In this raper, the inner structure of the washing machine is modeled as a rigid body suspension system and transfer farce caused by rotating unbalance mass is obtained using Newton's the 2nd law. and this model is used to predict the verge of walking instability during the spinning cycle. The walk of the drum washing machine is suggested by calculating the force transmissibility between drum and the cabinet. As calculating the resultant force exerted for cabinet, the friction coefficient of the pad is suggested to avoid the walk. In addition, relation between translational slip and rotational slip is derived and method to avoid the rotational slip is introduced.

• Bulletin of the Korean Chemical Society
• /
• 제17권4호
• /
• pp.365-373
• /
• 1996

Time profile of the transient grating signal induced by a nanosecond pulsed laser excitation of methyl red is investigated in alcohols and toluene at several solvent temperatures. The signal decays biexponentially with well-separated time constants; the faster decay is identified as due to thermal diffusion of the solvents and the slower one as mainly due to translational diffusion of the solute. The measured translational diffusion constants of methyl red in toluene are close to a hydrodynamic prediction with a slip boundary condition while those in alcohols are larger by 30% and increase slightly with the size of alcohols. We compare the results with modified hydrodynamic models.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.2753-2758
• /
• 2003

Tactile sensation is essential for many manipulation and exploration tasks not only in a real environment but also in a virtual environment. In this paper, we discuss a conceptual design of an integrated tactile display system. The system comprises two parts: a 2 DOF force feedback device for kinesthetic display and a tactile feedback device for displaying the normal stimulation to skin and the skin slip/stretch. Psychophysical experiments measure the effects of fingerpad selection, the direction of finger movements and the texture width on tactile sensitivity. We also investigate characteristics of lateral finger movement while subjects perceive different textures. From the experimental results, the principal parameters for designing a tactile display are suggested. A tactile display device is implemented using eight piezoelectric bimorphs and a linear actuator, and is attached to a 2 DOF translational force feedback device to simultaneously simulate texture and stiffness of the object.

• 제어로봇시스템학회논문지
• /
• 제14권11호
• /
• pp.1146-1154
• /
• 2008

This paper presents a method for the acceleration analysis of multi-legged walking robots in consideration of the frictional ground contact. This method is based on both unified dynamic equation for finding the acceleration of a robot's body and constraint equation for satisfying no-slip condition. After the dynamic equation representing relationship between actuator torques and body acceleration, is derived from the force and acceleration relationship between foot and body's gravity center, the constraint equation is formulated to reconfigure the maximum torque boundaries satisfying no-slip condition from given original actuator torque boundaries. From application of the reconfigured torques to the dynamic equation, interested acceleration boundaries are obtained. The approach based on above two equations, is adapted to the changes of degree-of-freedoms of legs as well as friction of ground. And the method provides the maximum translational and rotational acceleration boundaries of body's center that are achievable in every direction without occurring slipping at the contact points or saturating all actuators. Given the torque limits in infinite normsense, the resultant accelerations are derived as a polytope. From the proposed method, we obtained achievable acceleration boundaries of 4-legged and 6-legged walking robot system successfully.

• 제어로봇시스템학회논문지
• /
• 제11권5호
• /
• pp.445-450
• /
• 2005

In this paper, we suggest an integrated tactile display system that provides kinesthetic force, pressure distribution, vibration and slip/stretch. The system consists of two parts: a 2 DOF force feedback device for kinesthetic display and a tactile feedback device for displaying the normal stimulation to the skin and the skin slip/stretch. Psychophysical experiments measure the effects of fingerpad selection, the direction of finger movements and the texture width on tactile sensitivity. We also investigate the characteristics of lateral finger movement while subjects perceive different textures. From the experimental results, the principal parameters for designing a tactile display are suggested. A tactile display device, using eight piezoelectric bimorphs and a linear actuator, Is implemented and attached to a 2 DOF translational force feedback device to simultaneously simulate the texture and stiffness of the object. As a result, we find out that the capability of the suggested device is sufficient to display physical quantities to display the texture.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.383-386
• /
• 2005

An integrated analytical model which should have essential dynamics on the longitudinal railway vehicle is developed. The model consists of translational movement, rotational movement, brake actuator, adhesion force between rail and wheel, and brake friction force between wheel and pad. Thus, during the deceleration for stopping, a feedback controller controlling the brake cylinder pressure is designed to improve ride quality and to release friction problems. Through the developed model, the feasibility of controlling the cylinder pressure is verified for the better performances during braking.

• 한국지반신소재학회논문집
• /
• 제15권4호
• /
• pp.25-32
• /
• 2016

지반공학에서 평면변형율을 가정하는 2차원 사면안정해석은 일반적으로 널리 사용되고 있다. 이 가정은 사면활동이 넓은 영역에 걸쳐서 발생되는 가정이므로 3차원 효과가 무시된다. 대다수 연구에서 2차원해석의 최소안전율값은 3차원해석에 비하여 작게 평가되는 보수적인 결과를 나타낸다. 최근에는 컴퓨터의 소프트웨어와 하드웨어를 포함한 해석방법의 발달로 3차원해석에 대한 요구가 커지고 있다. 본 논문에서는 원호모드, 병진모드사면을 이용하여 유한요소에 의한 2, 3차원해석 및 2차원 한계평형해석을 통하여 수치해석을 실시하였다. 해석결과 매개변수(요소망크기, 체적팽창각(dilatency angle), 경계조건, 응력이력, 모델차원)에 따른 사면안정해석에 미치는 영향을 분석하였다. 해석결과 2차원 해석보다 3차원 해석에 의한 사면의 안전율 값은 항상 크게 평가되며, W 뱡향 경계조건이 롤러지지인 경우, 사면폭에 의한 결과 차이는 없는 것으로 조사되었다.