• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.122-124
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• 2003

This paper deals with the magnetic field analysis and compution of cogging torque using an analytical method in high speed brushless motor/generator. The magnetic field is analyzed by solving space harmonics field analysis due to magnetizing distribution and the cogging torque is analyzed by combining field analysis with relative permeance.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.11-15
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• 2014

Magnet gear transfers a high speed torque of the driving side to a low speed following side. Of course, the torque is amplified as much as a ratio between pole number of magnet gears constituting both sides through ferromagnet modulator. However, the parameters of the overall magnetic system influence the transmitting torque strongly. They include a pole number of permanent magnet, magnet thickness, reducing ratio, harmonic modulator thickness, and open ratio etc. In this paper, the influences of the parameters are analyzed using finite element method tool. By comparison, a desirable design specification is proposed, including a recommended modulator pattern.

• Design & Manufacturing
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• 제12권2호
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• pp.11-15
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• 2018

In this study, we proposed three analysis methods to calculate the flatness of torque-angle sensors (TAS). We introduced two statistical and one geometrical methods in evaluating the precision of the flat plane in the axis direction for TAS. To verified the results, we fabricated TAS and a reference sample using a injection molding machine, mold, polyester as a raw material. We measured ($x_i$, $y_i$) position using 3D contact automated system and applied three analysis methods developed for TAS and a reference sample to see the feasibility. While each analysis method has its own pros and cons, the analysis using the shortest optimal distance was the most precise technique for the flatness evaluation of TAS components.

• 한국산업융합학회 논문집
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• 제24권4_1호
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• pp.397-409
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• 2021

This study proposes a new approach to implimentation of robust control and torque control response analysis based on monitoring simulator for smart factory. According to the physical properties of a flexible manipulator, a two time-scale approach, namely, singular perturbation ap proach, is further utilized for thorough analysis and general controller design. It is shown that asymptotic motional tracking can be effectively achieved, whereas the force regulation errors can be made arbitrarily small. For demonstration of the proposed technology performance, experiments of a eight joint flexible manipulator are performed for the proposed control method, and the reliability of proposed control results are illustrated based on monitoring simulator.

• 소성∙가공
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• 제32권6호
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• pp.376-383
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• 2023

The torsion bar, which is a steering torque sensor, is mounted between the steering pinion and the input shaft in the IPA(input pinion assembly). Accurate torque measurement is important to improve the sense of operation, and the straightness of the torsion bar can affect torque measurement. In this study, the amount of bending was measured and the exact shape was analyzed regarding the bending phenomenon in the press-fitting process for torsion bars. The effect of alignment error was analyzed through finite element forming analysis. Process data analysis was conducted for the double-end press fit model. If there is an alignment error of about 10% of the serration tooth height, the indentation load is reduced by about 10%. If there is an alignment error, the torsion bar is rotated.

• 한국자기학회지
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• 제24권5호
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• pp.152-159
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• 2014

마그네틱 기어는 두 개 이상의 분리된 장치들 사이에서 기계적인 접촉 없이 토크를 전송한다. 특히, 희토류계 영구자석을 사용한 마그네틱 기어는 고 출력으로 인해 다양한 산업에 적용된다. 따라서 마그네틱 기어는 일반적인 기어를 대체할 수 있다. 본 논문에서는 이차원 유한요소해석을 이용해 평행방향과 할박 자화 마그네틱 기어의 기어비를 선정하고, 내측과 외측 영구자석 두께, 철심 각도, 할박 세그먼트 개수, 내측과 외측 영구자석 자화 패턴과 같은 설계 변수에 따라 토크 해석을 수행하였다. 해석 결과, 개선된 설계변수를 갖는 모델이 초기 설계 모델과 비교해 더 높은 토크를 가짐을 확인하였다.

• 수산해양기술연구
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• 제31권4호
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• pp.393-401
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• 1995

본 논문에서는 전압형제어에 의한 유도전동기의 토크 속응제어법의 메카니즘이 기술되어 졌다. 특히 본 논문에서는 펄스전압 인가에 의한 과도토크 소거원리를 전류레벨에서 해석함과 동시에 직관적 이해를 돕기 위해 벡터표현을 이용하여 제안 방식의 이론적 타당성을 입증하였다. 이상의 검토에서 얻어진 결과를 요약하면 다음과 같다. (1) 전압형제어에 있어서는 임펄스를 인가함으로써 스텝응답을 실현할 수 있다. (2) 유한 미소정정시간 $\Delta$를 매개로 정식화를 행함으로써, 토크의 스텝응답을 실현할 수 있는 이론적인 전압해 및 현실적으로 실현 가능한 전압해를 동시에 구할 수 있다. (3) 토크 속응제어를 $\Delta$이후의 과도전류가 0으로 되는 전압지령에 의해 실현하므로 펄스전압인가에 의한 스파이크 전류는 발생하지 않는다. (4) 전동기 정수가 불변 또는 실시간으로 동정된다면, 제안방식은 제어지령을 결정함에 있어서 전류정보에 직접 의존하지 않고도 피드포워드적으로 전압지령의 연산이 가능하다. 따라서 제어 시스템 구성의 간략화와 동시에 제어정도가 전류정보에 전적으로 의존하지 않는 제어계의 구축이 가능하다

• 대한치과보철학회지
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• 제44권6호
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• pp.722-733
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• 2006

Statement of problem. The use of small diameter implants having less than 3 mm in diameter were restricted because of lack of bonding strength to bone. Purpose. The purpose of this study was to observe how much resorbable blast media pin implants increase the binding force to the bone compared to machined transitional pin implants by measuring removal torque, and whether they can be used as final implants for replacement of small diameter teeth. Material and method. Fifteen rabbits were used in this study. Two kinds of implants (resorbable blast media pin implants and machined transitional pin implants) were inserted in each tibia bicortically. After healing time of 2, 4 and 8 weeks, the removal torque values were recorded and the rabbits were sacrificed for histological analysis. Linear finite element method analyses were conducted to compare bicortical fixation with monocortical fixation. Result and conclusion. Within the limitation of this in vivo study, the following conclusions were drawn: 1) The removal torque value of RBM pin implants showed statistically significant increase compared to machined pin implants at 2, 4, and 8 weeks respectively (p<0.05). 2) The removal torque value of RBM pin implants at 2, 4, and 8 weeks was increased statistically significantly with time (p<0.05). 3) Bicortical fixation showed better stress distribution compared with monocortical fixation in a linear finite element method analysis. 4) RBM pin implants are not recommended as transitional implants because they showed a lot of bone fracture in histologic specimens.

• The Journal of Advanced Prosthodontics
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• 제6권4호
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• pp.302-308
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• 2014

PURPOSE. The purpose of this study was to compare removal torques and surface topography between laser treated and sandblasted, large-grit, acid-etched (SLA) treated implants. MATERIALS AND METHODS. Laser-treated implants (experimental group) and SLA-treated implants (control group) 8 mm in length and 3.4 mm in diameter were inserted into both sides of the tibiae of 12 rabbits. Surface analysis was accomplished using a field emission scanning electron microscope (FE-SEM; Hitachi S-4800; Japan) under ${\times}25$, ${\times}150$ and ${\times}1,000$ magnification. Surface components were analyzed using energy dispersive spectroscopy (EDS). Rabbits were sacrificed after a 6-week healing period. The removal torque was measured using the MGT-12 digital torque meter (Mark-10 Co., Copiague, NY, USA). RESULTS. In the experimental group, the surface analysis showed uniform porous structures under ${\times}25$, ${\times}150$ and ${\times}1,000$ magnification. Pore sizes in the experimental group were 20-40 mm and consisted of numerous small pores, whereas pore sizes in the control group were 0.5-2.0 mm. EDS analysis showed no significant difference between the two groups. The mean removal torque in the laser-treated and the SLA-treated implant groups were 79.4 Ncm (SD = 20.4; range 34.6-104.3 Ncm) and 52.7 Ncm (SD = 17.2; range 18.7-73.8 Ncm), respectively. The removal torque in the laser-treated surface implant group was significantly higher than that in the control group (P=.004). CONCLUSION. In this study, removal torque values were significantly higher for laser-treated surface implants than for SLA-treated surface implants.

• Structural Engineering and Mechanics
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• 제80권5호
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• pp.503-522
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• 2021

This paper investigates experimentally and numerically the influence of drilling process on the mechanical and thermomechanical behaviors of woven glass fiber reinforced polymer (GFRP) composite plate. Through the experimental analysis, a CNC machine with cemented carbide drill (point angles 𝜙=118° and 6 mm diameter) was used to drill a woven GFRP laminated squared plate with a length of 36.6 mm and different thicknesses. A produced temperature during drilling "heat affected zone (HAZ)" was measured by two different procedures using thermal IR camera and thermocouples. A thrust force and cutting torque were measured by a Kistler 9272 dynamometer. The delamination factors were evaluated by the image processing technique. Finite element model (FEM) has been developed by using LS-Dyna to simulate the drilling processing and validate the thrust force and torque with those obtained by experimental technique. It is found that, the present finite element model has the capability to predict the force and torque efficiently at various drilling conditions. Numerical parametric analysis is presented to illustrate the influences of the speeding up, coefficient of friction, element type, and mass scaling effects on the calculated thrust force, torque and calculation's cost. It is found that, the cutting time can be adjusted by drilling parameters (feed, speed, and specimen thickness) to control the induced temperature and thus, the force, torque and delamination factor in drilling GFRP composites. The delamination of woven GFRP is accompanied with edge chipping, spalling, and uncut fibers.