• 한국시뮬레이션학회논문지
• /
• 제7권2호
• /
• pp.115-123
• /
• 1998

A simulation is performed to investigate the effect of the pipe supports on the change of the natural frequencies of curved pipe systems containing fluid flow, for different elbow angles and geometry of the pipe systems. Based upon the Hamilton's principle, the equations of motions are derived, and the finite element equation is constructed to solve the corresponding eigenvalue problem. The angles of elbows do not affect the change of the fundamental natural frequency, but affect the change of the third or higher natural frequencies. Without any support, the change of the fundamental natural frequency due to the geometric change is smaller than the change of the second or higher natural frequencies. The more curve parts exist in the pipe system, the less change of lower frequency range, compared with the change of higher frequency range, is observed. Spring supports can be used to reduce the fundamental natural frequency, without change of the second or higher natural frequencies. To avoid resonance, which is critically dangerous from the view point of structural dynamics, the mechanical properties such as stiffness or the location of pipe supports are need to be changed to isolate the natural frequencies from the frequency range of dominant vibration modes.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.842-848
• /
• 2011

The low-floor tram is a kind of railway vehicles which is operated on the street way track. For reducing the radius of curvature of the track, the tram consists of some carbody modules, and the articulation systems connect and support these carbody modules. The kind of articulation systems would be the hinge type and the pitching type. The hinge type articulation could allow only the yawing motion of the carbody modules, and the pitching type articulation could allow the pitching and yawing motions of the carbody modules simultaneously. With these function of the articulation systems, the tram could be operated on the horizontal and vertical curvature of the track. The number of each type of articulation could be decided with the number of carbody modules, and the manufacturer would decided the position of each type of the articulation in the view of the stability of carbody modules in the operation condition.

• 제어로봇시스템학회논문지
• /
• 제17권7호
• /
• pp.697-703
• /
• 2011

This article describes a snake robot with 2-DOF actuator modules. The 2-DOF actuator modules make the snake robot move in the 3D space so that the snake robot can cross obstacles and rough terrain. Each 2-DOF actuator module is designed to have high torque output and an embedded controller. A cross bracket connecting the modules is designed be able to support the weight of two actuator modules. The developed snake robot shows 3-D motions such as side winding, standing/monitoring, and can climb in a narrow pipe with high torque modules. The snake robot moves fast with passive wheels in a plane while crossing obstacles.

• 한국자동차공학회논문집
• /
• 제14권6호
• /
• pp.66-72
• /
• 2006

In this paper, an analytical investigation on the track separation mechanism for tracked excavator was studied. Relative motions of track links, sprocket, idler and support rollers are very important in the driving of an excavator The interference and friction between each components lead to noise and vibration. And also this has a great influence on the life for tracked excavator. RecurDyn program was used for the three dimensional modeling of the track assembly. Investigating the interference between sprocket and track links, the mechanism of the track separation was analyzed.

• ETRI Journal
• /
• 제30권6호
• /
• pp.757-764
• /
• 2008

In this paper, we present a design evaluation system with visualization and interaction of mobile devices using virtual-reality-based prototypes which can be used to easily change design parameters and simulate embedded software. To evaluate and predict affective-engineering-based design preferences for mobile devices under a virtual environment, we have developed a high quality visualization platform which creates images that look similar to real mobile devices in addition to real-time simulation of realistic motions and functions of mobile devices. To support a quantitative usability test scenario for external design shape, we also have built a system which consists of a mixed-reality-based testing platform for measuring hand load.

• 한국소음진동공학회논문집
• /
• 제14권1호
• /
• pp.64-72
• /
• 2004

In this paper. we analyse and present electro-mechanical dynamic characteristics of a micro-machined vibrating silicon ring gyroscope which can measure angular velocities about three orthogonal axes. The ring gyroscope has a ring connected to the gyroscope main body by support-ligaments which are arranged with cyclic symmetry. The natural modes of its vibration can be distinguished into the in-plane motion and the out-of-plane motion which are coupled by the gyro-effect due to the rotation of the gyroscope main body. The motions of the ring are electro-statically derived. sensed and balanced by electrodes. The equations of motion are formulated. The measuring method of angular velocities by force-to-rebalance is presented. The dynamic characteristics of a ring gyroscope are calculated and compared.

• 한국해안해양공학회지
• /
• 제11권4호
• /
• pp.231-237
• /
• 1999

다절점 케이블요소를 이용하여 조류하중을 받는 해양 케이블의 자유진동해석을 수행한다. 등매개 곡선 케이블요소(isoparametric cable element)의 접선강성행렬과 질량행렬을 유도하고, 하중증분법을 이용하여 지점 변위를 일으키고 자중, 부력, 그리고 조류력을 받는 케이블의 초기평형 상태를 결정한다. 초기의 정적평형상태를 기준으로 부가질량을 고려한 해양케이블의 자유진동해석을 수행한다. 수중케이블의 자유진동해석을 통하여 얻은 해석결과와 기존의 문헌의 결과를 비교, 검토함으로써 본 논문에서 제시한 이론 및 해석방법의 타당성을 입증한다.

• 제어로봇시스템학회논문지
• /
• 제10권11호
• /
• pp.1044-1051
• /
• 2004

This paper described a novel locomotion interface that can generate infinite floor for various surface, named as virtual walking machine. This interface allows users to participate in a life-like walking experience in virtual environments, which include various terrains such as plains, slopes and stair ground surfaces. The interface is composed of two three-DOF (X, Y, Yaw) planar devices and two four-DOF (Pitch, Roll, Z, and relative rotation) footpads. The planar devices are driven by AC servomotors for generating fast motions, while the footpad devices are driven by pneumatic actuators for continuous support of human weight. To simulate natural human walking, the locomotion interface design specification are acquired based on gait analysis and each mechanism is optimally designed and manufactured to satisfy the given requirements. The designed locomotion interface allows natural walking(step: 0.8m, height: 20cm, load capability: 100kg, slope:30deg) for various terrains.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.970-976
• /
• 2003

In this paper, we analyse and present electro-mechanical dynamic characteristics of a micro-machined vibrating silicon ring gyroscope which can measure angular velocities about three orthogonal axes. The ring gyroscope has a ring connected to the gyroscope main body by support-ligaments which are arranged with cyclic symmetry. The natural modes of its vibration can be distinguished into the in-plane motion and the out-of-plane motion which are coupled by the gyro-effect due to the notation of the gyroscope main body. The motions of the ring are electro-statically derived, sensed and balanced by electrodes. The equations of motion are formulated. The scheme of angular velocities sensing by force-to-rebalance method is presented. The dynamic characteristics of a ring gyroscope are calculated and compared.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1993년도 봄 학술발표회논문집
• /
• pp.173-180
• /
• 1993

주구조물의 여러층에 지지점을 가지는 부구조물의 응답스펙트럼 해석방법에 대하여 연구하였다. 본 연구에서는 지지점 입력간의 상관관계를 고려할 수 있으며 실무에서 부구조물의 내진설계에 쉽게 적용할 수 있는 다중 응답스펙트럼 해석방법을 제시하였다. 다중 응답스펙트럼과 지지점 입력간의 상관계수는 random vibration 이론을 이용하여 설계지반응웅답스펙트럼으로부터 직접 유도하였다. 예제해석 결과 본 연구에서 제안한 방법은 지지점 입력간의 상관관계를 고려하지 않는 통상의 다중 응답스펙트럼 해석방법보다 정확한 지진응답을 예측함을 알 수 있었다.