• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.765-768
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• 1995

A double parallel manipulator has only two or three links in each parallel mechanism. this reduces link interferences so that we expect a large workspace. To prove this property, this paper analyzes the workspace of a double parallel manipulator and compare it with that of a Stewart Platform. the analysis is separately conducted in a positional and an orientational division. For each, we obtain the workspace accrding to the ranges of lengths of links and show the volume in a cartesian coordinate or the angular ranges in yaw and pitch motions.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2001년도 춘계학술대회 논문집
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• pp.15-19
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• 2001

This paper describes effectiveness and characteristics of 3 P(point) task analysis as a new Ergonomic and Kansei design method for extracting user demand especially. The key point in 3 P task analysis is to describe the flow of tasks and extract any problems in each task. A solution of a problem means a user demand. 3 P task analysis cal eliminate an oversight of check items by examining the users' information processing level. The suers' information processing level was divided into the following three stages for problem extraction: acquirement of information ---> understanding and judgment ---> operation. Three stages has fourteenth cues such as difficulty of seeing, no emphasis, mapping for extracting problems. To link analysis results to the formulation of a product concept. I added a column on the right side of the table for writing the requirements (user demand) to resolve the problems extracted from each task. The requirements are extracted by using seventh cues. Finally 3 P task analysis was compared with group interview to make the characteristics of 3 P task analysis, especially extracting user demand, clear.

• Earthquakes and Structures
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• 제10권2호
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• pp.367-388
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• 2016

Eccentrically braced frames (EBFs) represent an attractive lateral load resisting steel system to be used in areas of high seismicity. In order to assess the likely damage for a given intensity of ground shaking, fragility functions can be used to identify the probability of exceeding a certain damage limit-state, given a certain response of a structure. This paper focuses on developing a set of fragility functions for EBF structures, considering that damage can be directly linked to the interstorey drift demand at each storey. This is done by performing a Monte Carlo Simulation of an analytical expression for the drift capacity of an EBF, where each term of the expression relies on either experimental testing results or mechanics-based reasoning. The analysis provides a set of fragility functions that can be used for three damage limit-states: concrete slab repair, damage requiring heat straightening of the link and damage requiring link replacement. Depending on the level of detail known about the EBF structure, in terms of its link section size, link length and storey number within a structure, the resulting fragility function can be refined and its associated dispersion reduced. This is done by using an analytical expression to estimate the median value of interstorey drift, which can be used in conjunction with an informed assumption of dispersion, or alternatively by using a MATLAB based tool that calculates the median and dispersion for each damage limit-state for a given set of user specified inputs about the EBF. However, a set of general fragility functions is also provided to enable quick assessment of the seismic performance of EBF structures at a regional scale.

• Journal of Power Electronics
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• 제11권6호
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• pp.787-792
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• 2011

In this paper, a new three phase soft switching inverter is presented. All of the semiconductor elements of this converter are soft switched. Employing only two auxiliary switches as DC-link switches and a simple control circuit are the advantages of the proposed inverter. The analytical equations and operating modes of the presented inverter are explained in details. The design considerations are presented and the experimental results verify the theoretical analysis.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.205-212
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• 1999

A three dimensional binary parallel robot manipulator uses actuators which have only two stable states and its structure is variable geometry truss. As a result, it has a finite number of states and fault tolerant mechanism because of kinematic redundancy. This kind of robot manipulator has some advantages compared to a traditional one. Feedback control is not required, task repeatability can be very high, and finite state actuators are generally inexpensive. Because the number of states of a binary robot manipulator grows exponentially with the number of actuators it is very difficult to solve and inverse kinematic problem. The goal of this paper is to develop an efficient algorithm to solve an inverse kinematic problem of three dimensional binary parallel robot manipulator using a backbone curve when the number of actuators are too much. We first derive the coordinate transformations associated with a three degree of freedom in-parallel actuated robot manipulator. The backbone curve is generated optimally by considering the maximum roll and pitch angles of the robot manipulator configuration and length of link. Then, the robot manipulator is fitted along the backbone curve with some criterion.

• 한국CDE학회논문집
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• 제15권5호
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• pp.383-392
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• 2010

The purpose of this study is to develop three Judo-doll systems for enhancement of Judo's performance. Traditional Judo training requires a human training partner. Unfortunately it is not always easy to find one. Multifunctional Judo-doll training system has therefore been developed, and is described here. The system consists of a dummy, a power generating mechanism, and kinematic links. The power-generating mechanism generates forces similar to those of a human, by adjusting deadweights and controlling powderbrake's forces. The powderbrake force is controlled by the microprocessor according to the exercise scenario. The kinetic links, which mimic a human training partner's motions, has been developed based on a $Vicon^{TM}$ system's analysis of the movement of human training partners. This mechanism whose name is "L link-wire" consists of L type links, wire, roller, and dead weight. This mechanism generates the force that leads the link to the neutral position regardless the link is pushed or pulled. The lifting mechanism that lifts the doll when the one-armed shoulder throw skill is applied is also developed. A 32-bit microprocessor controls the whole system; it reads the loadcell data, controls the electromagnetic force, and communicates with a PC via Bluetooth. The training history, including loadcell data, date, and training time, is stored in the PC for analysis. This training system can be used to enhance the Judo performance of any self training player.

• 한국정밀공학회지
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• 제18권11호
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• pp.138-147
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• 2001

Alignment systems are frequently used under various semiconductor manufacturing environment. Particularly in PDP(Plasma Display Panel) manufacturing process, the alignment system is applied to the combining and sealing processes of the upper and lower glass panels of PDP, where these processes are performed in the vacuum chamber of high vacuum and high temperature. In this paper, the XYΘ-alignment stage is developed to align PDP panels. Because of high vacuum and high temperature environment, the alignment chamber has been designed to isolate the inner part of the alignment chamber from the outer environment of high vacuum and high temperature, in which every part of the alignment stage is inserted. As it is difficult to attach feedback sensors to the alignment stage in the alignment chamber, the alignment stage is implemented with the open loop algorithm, where the parallel link structure has been designed using step-motors and ball-screws for structural simplicity. The kinematic analysis is performed to drive the parallel link structure, based on the experiments of actuation-compensation of the alignment stage. For the error compensation, the hyperpatch model has been used to model the errors. From the experiments, the positional accuracy of the alignment stage can be improved significantly.

• 소음진동
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• 제9권6호
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• pp.1259-1266
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• 1999

본 연구의 목적은 유연성 궤도 모델을 개발하여 고기동성 궤도차량의 다물체 동역학 해석에 응용하는 것이다. 유연성 궤도 모델을 개발하는데는 대체로 두 가지 어려운 문제가 따른다. 첫째로, 해의 안정성을 유지하기 위해 적분구간이 충분히 작아야 한다는 것이다. 즉, 궤도 링크 사이의 유연성 조인트 모델과 충격적인 접촉력에 따른 고진동 입력을 처리해야 한다. 둘째로, 3차원 다물체 궤도차량 모델에 대한 수 많은 운동 방정식을 풀어야 한다는 것이다. 따라서 궤도차량을 샤시와 궤도 부시스템으로 나누고 회귀적인 방법을 사용하여 운동방정식의 수를 최소화하였다. 본 연구에서 개발된 방법을 검증하기 위하여 차량의 가속, 고속주행, 제동, 선회 등의 시뮬레이션을 수행하였다.

• Journal of Biosystems Engineering
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• 제9권2호
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• pp.48-57
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• 1984

To analyze the grain transport velocity, which is valuable for optimizing the separation losses, an oscillating appratus for sieve was designed. The grain transport velocity was measured in each combination of three amplitude levels, three rpm levels and four projection angle levels. To analyze the grain transport velocity theortically, two computer programs were developed. And the results from experiment and theoretical analysis were compared. 1. The grain transport velocity was increased with the projection angle of oscillating sieve. Especially when the projection angle is higher than $45^{\circ}$ the grain transport velocity on the flat-plate was not increased but on the racked surface was increased persistently. 2. The grain transport velocity was increased linearly with the frequency of oscillating motion. The speed of driving link must be higher than 350 rpm at 24mm amplitude, 250 rpm at 36 mm amplitude to transport the grain efficiently. 3. The grain transport velocity was increased with the amplitude of oscillating motion. But if the amplitude was smaller than interval of racks, the grain on the racked surface was not transported, even though the projection angle or the speed of revolutionary link was increased. 4. The transport characteristics of a grain varied with the amplitude and projection angle. Especially in the range of 1.5 < K < 2.3 at $45^{\circ}$ projection angle the transportation of grain was successful and the grain motion consisted of sliding movement (forward, backward) and jumping movement, which is considered recommendable for separating process of a combine sieve. 5. The results from theoretical analysis were approximately in accord with that from experiment.

• Journal of Power Electronics
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• 제18권6호
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• pp.1819-1829
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• 2018

A three-phase, three-switch, and three-level boost-type PWM rectifier (Vienna rectifier) is proposed as an active front-end power factor correction (PFC) rectifier for telecom loads. The proposed active front-end PFC rectifier system is modeled by the switching cycle average model. The relation between duty ratios and DC link capacitor voltages is derived in terms of the system input currents. Furthermore, the feasible switching states are identified and applied to the proposed system to reduce the switching stress and DC ripples. A detailed equivalent circuit analysis of the proposed front-end PFC rectifier is conducted, and its performance is verified through simulations in MATLAB. Simulation results are verified using an experimental setup of an active front-end PFC rectifier that was developed in the laboratory. Simulation and experimental results demonstrate the improved power quality parameters that are in accordance with the IEEE and IEC standards.