• Title/Summary/Keyword: Kinematical analysis

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Comparisons of Kinematical Analysis for the Universal-joint System by Using Finite Rotations and Quaternions (유한회전과 4원수를 이용한 유니버설 조인트 시스템의 기구해석 비교)

  • Yun, Seong-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.2
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    • pp.183-189
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    • 2010
  • This paper deals with the comparison of analysis methodologies by applying both Euler angle and quaternion to observe the kinematical behavior of the universal joint system used as an automotive drive-shaft. At first, conventional approaches are applied to predict a kinematical behavior by introducing only Euler angles into the universal joint system, but turns out to be lack in consistency and reliability of the analysis. Then to overcome this deficiency in numerical analysis a different methodology is proposed by using quaternion in this system. Its corresponding advantage is discussed in terms of kinetic energy, rotational velocity and rotational displacement. The application of quaternions in the numerical experiment is shown to be a more useful and valid way of establishing the ideal analytical model of the universal joint system.

A Study on Kinematical Modeling and Analysis of Double Side Wafer Polishing Process (실리콘 웨이퍼 양면 연마 공정의 기구학적 모델링과 해석에 관한 연구)

  • Lee, Sang-Jik;Jeong, Suk-Hoon;Lee, Hyun-Seop;Park, Sun-Joon;Kim, Young-Min;Jeong, Hae-Do
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.485-485
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    • 2009
  • Double side polishing process has been used for various industrial applications, such as polishing of semiconductor substrates and flat panel display glasses. In wafer manufacturing, double side polishing process is applied to improve wafer flatness and to minimize particle generation from wafers in device manufacturing processes, which is recognized as one of the most important processes. Whereas the kinematical modeling and analysis results of single side polishing, extensively used for chemical-mechanical polishing (CMP) in device manufacturing, are well investigated, the studies in conjunction with double side polishing are barely carried out, due to the complication of polishing system and the uncertainty of wafer motion in the carrier. This paper suggests the derivation of kinematical model with consideration of carrier and wafer motion in double side polishing, and then presents the effect of kinematical parameters on material removal amount and its non-uniformity. The kinematical analysis results help to understand the double side polishing process and to control the polishing results.

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Kinematical Analysis and Vibrational Characteristics of Orthogonal 2-dimensional Vibration Assisted Cutting Device (직교형 2차원 진동절삭기의 기구학적 해석 및 진동 특성 고찰)

  • Loh, Byoung-Gook;Kim, Gi-Dae
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.9
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    • pp.903-909
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    • 2012
  • In elliptical vibration cutting(EVC) where the cutting tool traces a micro-scale 2-dimensional elliptical trajectory, the kinematical and vibrational characteristics of the EVC device greatly affect cutting performance. In this study, kinematical and vibrational characteristics of an EVC device constructed with two orthogonally-arranged stacked piezoelectric actuators were investigated both analytically and experimentally. The step voltage was applied to the orthogonal EVC device and the associated displacements of the cutting tool were measured to assess kinematical characteristics of the orthogonal EVC device. To investigate the vibrational characteristic of the orthogonal EVC, sinusoidal voltage was applied to the EVC device and the resulting displacements were measured. It was found from experiments that coupling of displacements in the thrust and cutting directions and the tilt of the major axis of the elliptical trajectory exists. In addition, as the excitation frequency is in vicinity of resonant frequencies the distortion in the shape of the elliptical trajectory becomes greater and change in the rotation direction occurs. To correct the shape distortion of the elliptical trajectory, the shape correcting procedure developed for the parallel EVC device was applied for the orthogonal EVC device and it was shown that the shape correcting method successfully corrects distortion.

An Analytical Investigation on the Ratio of Angular Velocity in Spherical Involute Bevel Gearsets (구형 인볼류트 베벨기어쌍의 각속도비에 관한 해석적 연구)

  • Park, N.G.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.5
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    • pp.40-45
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    • 1995
  • The kinematical relationship of bevel gearsets lies at the root of the gear design. As the demand on precision bevel gears is increased in the related industries, the kinematic analysis of a pair of sperical involute bevel gears needs to be exactly evaluated for the computer aided design. Pitch cone angles of bevel gearsets have been calculated under the assumption that the geared system is equivalent to a coned roller system without slipping. But this kinematical model involves some errors in the value of the ratio of angular velocity. In this paper, the ratio of the angular velocity is exactly derived, based on the perfect involute tooth surface. Four nonlinear equations representing the kinematical relationships are numerically solved to obtain the pitch and base cone angles. The ratios of angular volocities according to pressure and shaft angles are calculated and compared with those of the approximate gear model.

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Kinematical Characteristics of Vibration Assisted Cutting Device Constructed with Parallel Piezoelectric Stacked Actuators (평행한 적층 압전 액추에이터로 구성된 진동절삭기의 기구학적 특성 고찰)

  • Loh, Byoung-Gook;Kim, Gi-Dae
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.12
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    • pp.1185-1191
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    • 2011
  • The kinematic characteristics of cutting device significantly affects cutting performance in 2-dimensional elliptical vibration cutting(EVC) where the cutting tool cuts workpiece, traversing a micro-scale elliptical trajectory in a trochoidal motion. In this study, kinematical characteristics of EVC device constructed with two parallel stacked piezoelectric actuators were analytically modeled and compared with the experimental results. The EVC device was subjected to step and low-frequency(0.1 Hz) sinusoidal inputs to reveal only its kinematical displacement characteristics. Hysteresis in the motion of the device was observed in the thrust direction and distinctive skew of the major axis of the elliptical trajectory of the cutting tool was also noticed. Discrepancy in the voltage-to-displacement characteristics of the piezoelectric actuators was found to largely contribute to the skew of the major axis of the elliptical trajectory of the cutting tool. Analytical kinematical model predicted the cutting direction displacement within 10 % error in magnitude with no phase error, but in estimating the thrust direction displacement, it showed a $27^{\circ}$ of phase-lag compared with the measured displacement with no magnitude error.

A Kinematical Analysis of the Kenmotsu on the Parallel Bars (평행봉 Kenmotsu 동작의 운동학적 분석)

  • Kong, Tae-Ung;Kim, Young-Sun;Yoon, Chang-Sun
    • Korean Journal of Applied Biomechanics
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    • v.15 no.3
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    • pp.61-70
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    • 2005
  • The purpose of study was to investigate the kinematic variables of Kenmotsu motion in Parallel bars. To this study, by 3 dimensional kinematical analysis of 4 male national gymnasts participants in the 28th Athens Olympic Game in 2004, kinematic data collected using video camera. Coordinate data were smoothed by using a fourth-order Butterworth low pass digital filter with cutoff frequency of 6Hz. The conclusions were as follows. 1. In P2, because the constrained swing movement made the movement of a rising back difficult7, the movements of Reg. were performed at low position after Air phase. 2. In E5 event, for the shake of a stable handstand and applied techniques like a Belle(E-value), a Belle Piked(super E-value), a vertical velocity in E2, a horizontal velocity in E3 and a vertical velocity in E4 were necessary for high velocities. 3. In E4 event, it was appeared that for a flexible body's movement of a vertical up-flight, the large angle of the shoulder joint and the flexion & extension of the hip joint were necessary in Air phase and a long flight time and vertical displacement made Reg. movements stable at the high position.

Kinematical Analysis of El-grip swing with 1turn to el-grip in horizontal bar (철봉 어깨 틀어 휘돌아 다시 잡기(el-grip swing with one turn to el-grip) 동작의 운동학적 분석)

  • Kim, Jae-Phil
    • Korean Journal of Applied Biomechanics
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    • v.13 no.1
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    • pp.51-62
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    • 2003
  • This study was attempted to kinematical characteristics of the El-grip swing with 1turn to el-grip in elite horizontal bar for the purpose of improving performance. The subjects were three males who were 2002 Busan Asian Games in men's team. The three dimensional motion analysis with DLT method was executed using three video cameras of analyzing the actual competition situation. In point of analyzing the actual competition situation, it is expected that gymnastics and coaches have the effective informations, and the following conclusion had resulted. 1. In case of release, It is impotant to make fast horizontal velocity of CM, high vertical position of CM, large hip and shoulder angle. Also It should be performed release motion of trunk rotation angle(+). 2. During LHR the action should be made at higher position than the CM and the shoulder joint is moving within $127{\pm}16.82$. It is important to make large lunk rotation angle. 3. During Hop, the RHR motion should be done in high position with short time and fast twisting action and to reduce the vertical speed is important.

The Application of Qualitative Evaluation for Golf Swills field Lesson (골프스윙 현장지도를 위한 정성적 평가 적용)

  • Yu, Seung-Won
    • Korean Journal of Applied Biomechanics
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    • v.19 no.2
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    • pp.323-336
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    • 2009
  • The purpose of the current study was to research scientific basis and necessity of supplementary materials for field lesson out of golf swing teaching methods. As the subject of study, skillful tour pro golfers were chosen to reinterpret field lesson results for driver swing from the viewpoint of kinematics. In addition, through precise analysis, this study developed a case to verify the validity and error of field lesson. As a result, field lesson showed a slight difference among qualitative evaluation of kinematical analysis of techniques, subjects of study, and items. Accordingly, there was a little difference between two methods in view of evaluation of errors that 5 subjects of the study have shown. However, there was a significant difference in compensation to prevent causes of error and errors. Based on instructor's experience most errors could be evaluated. Therefore, feedback for error correction based on instructor's experience showed a significant difference from qualitative evaluation of kinematical analysis of techniques. In conclusion, the following are required for correct golf swing lesson; instant feedback through field lesson and qualitative evaluation of kinematical analysis of techniques to determine fundamental causes correctly.

A 3D FEA Model with Plastic Shots for Evaluation of Peening Residual Stress due to Multi-Impacts (다중충돌 피닝잔류응력 평가를 위한 소성숏이 포함된 3차원 유한요소해석 모델)

  • Kim, Tae-Hyung;Lee, Hyungy-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.8
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    • pp.642-653
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    • 2008
  • In this paper, we propose a 3-D finite element (FE) analysis model with combined physical behavior and kinematical impact factors for evaluation of residual stress in multi-impact shot peening. The FE model considers both physical behavior of material and characteristics of kinematical impact. The physical parameters include elastic-plastic FE modeling of shot ball, material damping coefficient, dynamic friction coefficient. The kinematical parameters include impact velocity and diameter of shot ball. Multi-impact FE model consists of 3-D symmetry-cell. We can describe a certain repeated area of peened specimen under equibiaxial residual stress by the cell. With the cell model, we investigate the FE peening coverage, dependency on the impact sequence, effect of repeated cycle. The proposed FE model provides converged and unique solution of surface stress, maximum compressive residual stress and deformation depth at four impact positions. Further, in contrast to the rigid and elastic shots, plastically deformable shot produces residual stresses closer to experimental solutions by X-ray diffraction. Consequently, it is confirmed that the FE model with peening factors and plastic shot is valid for multi-shot peening analyses.