• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.163-166
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• 2001

It leaves much room for improvement that UTM-01 is of practical use. Therefor we will design of longitudinal pole magnet for UTM-02 system. The design of new magnet is based on light weight for bogie system. The new magnet for UTM-02 was reduced weight of magnet is 18kg per one, then it was ratio lift to weight is 10.13.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.34-36
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• 1999

2 phase 8 pole HB type LPM(linear pulse motor) has the suitable structure for it's microstep drive. Hence, if this LPM will be drived by this method, the limited(mechanically) step resolution can be increased further and vibration and noise can be decreased considerably. But, It is difficult that this LPM was analyzed in detail because of it's complex magnetic circuits to be composed the LF(longitudinal flux) and TF(transverse flux.) path. If LPM was analyzed by the approximate 2D model, we could not be obtained satisfactory result. Therefore, It is necessary to be analyzed the 3D model in detail for the more satisfactory results. In this paper, we obtain 3D flux distribution of the mover using by 3D FEM(finite element method)

• Structural Monitoring and Maintenance
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• 제9권1호
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• pp.29-42
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• 2022

In mountainous areas of China, concrete poles with connectors are widely employed in power transmission due to its convenience of manufacture and transportation. The bearing capacity of the poles must have degenerated over time, and most of the steel connectors have been corroded. Carbon fiber reinforced polymer (CFRP) offers a durable, light-weight alternative in strengthening those poles that have served for many years. In this paper, the bearing capacity and failure mechanism of CFRP sheet strengthened existing reinforced concrete poles with corrosion steel connectors were investigated. Four poles were selected to conduct flexural capacity test. Two poles were strengthened by single-layer longitudinal CFRP sheet, one pole was strengthened by double-layer longitudinal CFRP sheets and the last specimen was not strengthened. Results indicate that the failure is mainly bond failure between concrete and the external CFRP sheet, and the specimens fail in a brittle pattern. The cross-sectional strains of specimens approximately follow the plane section assumption in the early stage of loading, but the strain in the tensile zone no longer conforms to this assumption when the load approaches the failure load. Also, bearing capacity and stiffness of the strengthened specimens are much larger than those without CFRP sheet. The bearing capacity, initial stiffness and elastic-plastic stiffness of specimen strengthened by double-layer CFRP are larger than those strengthened by single-layer CFRP. Weighting the cost-effective effect, it is more economical and reasonable to strengthen with single-layer CFRP sheet. The results can provide a reference to the same type of poles for strengthening design.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2105-2114
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• 2006

In this paper, a simplified model is studied to predict analytically the vibration from the helical gear system due to an axial excitation of helical gears. The simplified model describes gear, shaft, bearing, and housing. In order to obtain the axial force of helical gears, the mesh stiffness is calculated in the load deflection relation. The axial force is obtained from the solution of the equation of motion, using the mesh stiffness. It is used as a longitudinal excitation of the shaft, which in turn drives the gear housing through the bearing. In this study, the shaft is modeled as a rod, while the bearing is modeled as a parallel spring and damper only supporting longitudinal forces. The gear housing is modeled as a clamped circular plate with viscous damping. For the modeling of this system, transfer matrices for the rod and bearing are used, using a spectral method with four pole parameters. The model is validated by finite element analysis. Using the model, parameter studies are carried out. As a result, the linearized dynamic shaft force due to the gear excitation in the frequency domain was proposed. Out-of-plan displacement from the forced vibrating circular plate and the renewed mode normalization constant of the circular plate were also proposed. In order to control the axial vibration of the helical gear system, the plate was more important than the shaft and the bearing. Finally, the effect of the dominant design parameters for the gear system can be investigated by this model.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2002년도 추계학술발표논문집
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• pp.74-80
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• 2002

A mathematical tension model for a moving web in a multi-span web handling system was derived and validated by using a simulator which includes unwinder, driven roller, winder, load cells, controllers, etc. A tension controller was designed to compensate tension disturbances generated by velocity changes of the unwinder and driven roller. From experimental results it was proved that the tension model properly expressed the tension behavior of a moving web for specific conditions. The distributed tension controller designed by using the pole-placement technique compensated the tension disturbances transfered from upsteram tension variation. Interactions between web spans including "tension transfer phenomenon" were clearly confirmed through the study. A mathematical model of lateral motion of a moving web was verified also by using the same experimental apparatus which includes displacement type guidance systems. And a feedforward control strategy was designed for more accurate control of the lateral motion of a moving web, which utilize a measured signal of the lateral displacement of web in a previous span and a more correctly identified mathematical model to estimate the disturbance of lateral motion from the previous span. This approach was turned out to be effective in improving the performance of the guidance system for more wide range disturbances.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.199-203
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• 2004

In this paper, a simplified model is studied to predict analytically the radiated noise from the helical gear system due to an axial excitation of helical gear. The simplified model describes gear, shaft, bearing, and housing. To obtain the axial force of helical gear, mesh stiffness is calculated in the load deflection relation. The axial force is obtained from the solution of the equation of motion, using the mesh stiffness. It is used as a longitudinal excitation of the shaft, which in turn drives the gear housing through the bearing. In this study, the shaft is modeled as a rod, while the bearing is modeled as a parallel spring and damper only supporting longitudinal forces. The gear housing is modeled as a clamped circular plate with viscous damping. For the modeling of this system, transfer function from the shaft to the clamped plate are used, using a spectral method with four pole parameters. Out-of-plane displacement for the thin circular plate with viscous damping is derived and sound pressure radiated from the plate is also derived. Using the model, parameter studies are carried out.

• 제어로봇시스템학회논문지
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• 제7권1호
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• pp.1162-1170
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• 2001

This paper proposes a practical gain-scheduling control law considering robust stability and performance of Linear Parameter Varying(LPV) systems in the presence of nonlinearities and uncertainties. The proposed method introduces LMI-based pole placement synthesis and also associates with a recently developed fuzzy control system based on Takagei-Sugenos fuzzy model. The sufficient conditions for robust controller design of linearized local dynamics and robust stabilization of fuzzy control systems are reduced to a finite set of Linear Matrix inequalities(LMIs) and solved by using co-evolutionary algorithms. The proposed method is applied to the longitudinal acceleration control of high performance aircraft with linear and nonlinear simulations.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2162-2169
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• 2015

Cruise control is a technology for automatically maintaining a steady speed of vehicle as set by the driver via controlling throttle valve and brake of vehicle. In this paper we investigate cruise controller design method with consideration for distance to vehicle ahead. We employ linear time varying (LTV) model to describe longitudinal vehicle dynamic motion. With this LTV system we approximately model the nonlinear dynamics of vehicle speed by frequent update of the system parameters. In addition we reformulate the LTV system by transforming distance to leading vehicle into variation of system parameters of the model. Note that in conventional control problem formulation this distance is considered as disturbance which should be rejected. Consequently a controller can be designed by pole placement at each instance of parameter update, based on the linear model with the present system parameters. The validity of this design method is examined by simulation study.

• 한국산학기술학회논문지
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• 제17권3호
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• pp.310-316
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• 2016

도전성 평판에 부분적으로 걸쳐 회전하는 축형 동전기 휠을 구동원으로 이용하는 비접촉 반송 시스템을 제안한다. 회전하는 동전기 휠에는 3축력이 발생되는데 이 중 중력방향 힘과 횡방향 힘은 자기안정성을 갖고 있으므로 공간상에서 반송 시스템의 동적 안정성을 확보하기 위해서는 길이 방향 힘만을 제어하는 것으로 충분하다. 동전기 휠은 원주 방향을 따라 주기적으로 반복되는 극성을 갖는 영구자석으로 구성되어있으므로 기본 극의 기하학적 형상이나 극수 등은 안정성 여유에 큰 영향을 미친다. 또한 휠과 전도판간의 중첩된 영역 역시 횡방향으로의 강성을 결정하는 주요 인자이므로 본 논문에서는 안정성을 성능 지표로 휠을 구성하는 주요 설계 변수에 대한 민감도 해석을 수행한다. 얻어진 설계 값을 이용하여 제작된 시스템으로 휠을 포함하는 이동 개체의 수동적인 안정성을 실험적으로 검증한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.481-488
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• 2008

전차선로 상세설계는 평면도(pegging plan) 작업과 장주도 작업으로 분류될 수 있다. 평면도 작업은 선로 방향으로 전주의 위치, 편위, 장력길이 등을 결정하여 설계하는 것이고, 장주도 작업은 전주 위치에서 선로에 직각방향의 도면을 그리는 작업으로, 장주도에서는 전주, 기초, 가동브래킷, 전차선 및 조가선을 포함한 모든 선 등의 위치 및 크기 등을 확인할 수 있고, 장주별 사용된 자재를 표시한다. 본 연구에서는 입력조건 및 선로조건 등에 따라 기존선 180km/h급 전차선로의 장주도를 자동으로 설계할 수 있는 프로그램을 개발하였다. 그리고, 본 프로그램을 통하여 사용한 자재를 장주별 / 섹션별로 관리할 수 있고, 드로퍼 길이를 자동으로 계산할 수 있도록 하였다. 본 프로그램의 입력 및 계산은 C#을 이용하여 MS Excel 2007 기반의 친숙한 구조의 GUI를 개발하였으며, 장주도 출력에는 C#(ObjectARX)를 이용하여 개발하였다.