• Journal of Biosystems Engineering
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• v.7 no.2
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• pp.8-17
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• 1983

특수(特殊)한 기능(機能)을 수행(遂行)하기 위한 4링크 기구(機構)의 설계(設計)에서는 링크의 연간궤적(連稈軌跡)이 중요(重要)한 설계조건(設計條件)이 된다. 이앙기(移秧機)의 이식기구(移植機構)나 바인던의 방출(放出)암은 모두 4링크 기구(機構)를 이용(利用)하여 작업수행(作業遂行)에 필요(必要)한 연간궤적(連稈軌跡)을 얻고 있는 것이다. 필요(必要)한 연간궤적(連稈軌跡)을 얻기위한 4링크 기구(機構)의 합성(合成)은 도해적(圖解的), 해석적(解析的) 방법(方法)을 통(通)하여 많은 연구(硏究)가 이루어져 왔으며 최근(最近)에는 콤퓨터를 이용(利用)한 기구합성(機構合成)에 대(對)한 연구(硏究)가 활발하게 이루어지고 있다. 본(本) 연구(硏究)에서는 연간궤적상(連稈軌跡上)의 점(點)들을 이용(利用)하여 주어진 연간궤적(連稈軌跡)을 얻기 위한 4링크 기구(機構)의 합성(合成)에 대(對)한 새로운 방법(方法)을 개발(開發)하고 이 방법(方法)을 콤퓨터 프로그래밍하여 주어진 연간궤적(連稈軌跡)과 콤퓨터로 합성(合成)한 4링크 기구(機構)의 연간궤적(連稈軌跡)을 비교(比較)검토 하였다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.216-223
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• 2000

A robot arm with free joints has some advantages over conventional ones. A light weight and low power consumed arm can be made by a reduction of the number of joint actuators. And this arm can easily overcomes actuator failure due to unexpected accident. In general such underactuated arm does not have controllability because of the lack of joint actuators. The two-link arm with a free joint introduced in this paper is also uncontrollable in the sense of linear system theory. However, the linearized system sometimes can not represent the inherent dynamic behavior of the nonlinear system. In this paper the dynamic characteristics of the two-link arm with a free joint in view of global motion including damping and friction effect of the joints is investigated. In the case of considering only the damping effect, the controllable goal positions are confined to a specific trajectories. But in the case of considering the friction effect, the system can be controlled to arbitrary positions using the friction of the free joint as a holding brake. Also numerical example of position control is presented.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.113-130
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• 2002

In this paper, we developed DNL(Dynamic Network Loading) model based on Moving cell theory to analyze the dynamic characteristics of traffic flow in congested network. In this paper vehicles entered into link at same interval would construct one cell, and the cells moved according to Cell following rule. In the past researches relating to DNL model a continuous single link is separated into two sections such as running section and queuing section to describe physical queue so that various dynamic states generated in real link are only simplified by running and queuing state. However, the approach has some difficulties in simulating various dynamic flow characteristics. To overcome these problems, we present Moving cell theory which is developed by combining Car following theory and Lagrangian method mainly using for the analysis of air pollutants dispersion. In Moving cell theory platoons are represented by cells and each cell is processed by Cell following theory. This type of simulation model is firstly presented by Cremer et al(1999). However they did not develop merging and diverging model because their model was applied to basic freeway section. Moreover they set the number of vehicles which can be included in one cell in one interval so this formulation cant apply to signalized intersection in urban network. To solve these difficulties we develop new approach using Moving cell theory and simulate traffic flow dynamics continuously by movement and state transition of the cells. The developed model are played on simple network including merging and diverging section and it shows improved abilities to describe flow dynamics comparing past DNL models.

• Journal of the Korea Convergence Society
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• v.6 no.1
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• pp.57-63
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• 2015

In this study, the lower arm is connected and fixed at the model of the automotive stabilizer link as the moment is applied. There are models of 1, 2 and 3 as a length control type, a general type and a single body type respectively. These models are investigated by performing the convergence technique through the design and the strength analysis with CATIA and ANSYS. As the maximum equivalent stress of model 3 has the least, model 3 can endure the highest load among three models. As the fatigue analysis, model 3 has the minimum blocks as the frequency of stress state, model 3 becomes also safest among three models. As models of 1, 2 are in the order of the next safety, the number of blocks becomes larger as the frequency of stress state and the instability becomes higher. And it is possible to be grafted onto the convergence technique at design and show the esthetic sense.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.2
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• pp.94-101
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• 1996

The equations of motion for a basic industrial robotic system which has a rigid or a flexible arm are derived by Lagrange's equation, respectively. Especially, for the deflection of the flexible arm, the assumed mode method is employed. These equations are highly nonlinear equations with nonlinear coupling between the variables of motion. In order to design the control law for the rigid-arm robot, Hunt-Su's nonlinear transformation method and Marino's feedback equivalence condition are used with linear quadratic regulator(LQR) theory. The control law for the rigid-arm robot is employed to input the desired path and to provide the required nonlinear transformations for the flexible-arm robot to follow. By using the implicit Euler method to solve the nonlinear equations, the comparison of the motions between the flexible and the rigid robots and the effect of flexibility are examined.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.1
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• pp.144-153
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• 1997

The determination of the direct kinematics of the parallel mechanism is a difficult problem but has to be solved for any practical use. This paper presents the efficient formulation of the direct kinematics for double parallel robot arm. The robot arm consists of two parallel mechanism, which generate positional and orientational motions, respectively. These motions are decoupled by a passive central axis which is composed of four revolute joints and one prismatic joint. For a set of given lengths of linear actuators, the direct kinematics will find the joint displacements of th central axis from geometric constraints in each parallel mechanism. Then the joint displacements will be converted into the position and the orientation of the end effector of the robot arm. The proposed formulation is decoupled and compacted so that it will be implemented as a real-time direct kinematics. With the proposed formulation, we analyze the motion of the double parallel robot and show its characteristics. Specially, we investigate the workspace in terms of positional space as well as orientational space.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.33-43
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• 2002

Travel choice behavior is affected by real-time traffic information. Recently, in urban area, real-time traffic information is provided by several instruments such as transportation broadcasting, internet PC network and variable message sign, etc. Furthermore, it has been increasing for urban travelers to use real-time traffic information provided by several instruments. The purpose of this study is to analyze the effects of advanced traveler information on urban worker's travel choice behavior. Among several Advanced Traveler Information System(ATIS) employed in urban area. This study focuses on examining the effects of transportation broadcasting on urban worker's travel choice behavior. This study attempts to examine traveler's mode change behavior in the pre-trip stage and traveler's route change behavior in the on-route stage. For this study, the survey data collected from Daegu City in 2000 is used. For empirical analysis, several nested logit models are estimated, and among them, the best models are reported in this paper. Furthermore, based on the empirical models estimated for this research, important findings and their policy implications are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.1-8
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• 2008

We propose how to program the off-line buffing robot path along shoes' outsole shape in the footwear buffing process by a 5-axis microscribe system like robot mechanism. The microscribe system we developed consists of a 5-axis robot link with a turn table, a signal processing unit, PC and an application software program. Itmakes a robot path on the shoes' upper in accordance with the movement of a microscribe with many joints. The developed system calculates the encoder pulse values for the microscribe arm's rotation and transmits the angle pulse values to the PC through a processing unit. Denavit-Hartenberg's(D-H) direct kinematics is used to make the global coordinate from microscribe joint one. Problems with the microscribe's kinematics can be solved efficiently and systematically by D-H representation. With the coordinate values calculated by D-H equation, our system can draw a buffing gauge-line on the upper sole. We obtain shoes' outline points, which are 2 outlines coupled with the points and the normal vector based on the points. By applying the system to the buffing robot in a flexible manufacturing system, it can be used effectively to program the path of a real buffing robot.