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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
Journal Basic Information
Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 25, Issue 12 - Dec 2008
Volume 25, Issue 11 - Nov 2008
Volume 25, Issue 10 - Oct 2008
Volume 25, Issue 9 - Sep 2008
Volume 25, Issue 8 - Aug 2008
Volume 25, Issue 7 - Jul 2008
Volume 25, Issue 6 - Jun 2008
Volume 25, Issue 5 - May 2008
Volume 25, Issue 4 - Apr 2008
Volume 25, Issue 3 - Mar 2008
Volume 25, Issue 2 - Feb 2008
Volume 25, Issue 1 - Jan 2008
Selecting the target year
Current Status and Future Prospects of Solar Cells
Lee, Jae-Hyeong ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 7~22
Status of Technology Development for Applying Solar Thermal Energy in Korea
Lee, Ju-Han ; Seo, Tae-Beom ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 23~32
Solar Daylighting System
Kim, Sun-Ho ; Kim, Byung-Cheol ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 33~40
Characterization of AFM machining mode and Acoustic Emission monitoring
Ahn, Byoung-Woon ; Lee, Seoung-Hwan ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 41~47
This study aims to obtain machining characteristics during AFM (Atomic force Microscope) machining of silicon wafers and to monitor the machining states using acoustic emission. As in micro scale machining, two distinct regimes of deformation, i. e. ploughing regime and cutting regime were observed. First, the transition between the two regimes are investigated by analyzing the "pile-up" during machining. As far as in process monitoring is concerned, in the ploughing repime, no chips have been formed and related AE RMS values are relatively low, In the mean time, in the cutting regime, the RMS values are significantly higher than the ploughing regime, with apparent chip formation. From the results, we found out that the proposed scheme can be used for the monitoring of nanomachining, especially for the characterization of nanocutting mode transition.
Magnetic Circuit Design Methodology of MR CDC Dampers for Semi-Active Suspensions
Park, Jae-Woo ; Jung, Young-Dae ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 48~57
MR Fluid, one of functional fluids, is developed for the application to automobile products. MR CDC damper using MR fluid has following principles. When ar electric current is applied to the solenoid, apparent viscosity of MR fluid passing through the annular gap which acts as magnetic circuits varies directly as the intensity of the current. These devices have a simple structure and excellent lime response characteristics, emerging as the alternatives of the conventional semi-active suspension systems. In this study, a design procedure of the magnetic circuit through the solenoid fore and the flux ring functioning as a magnetic path is investigated so as to optimize the design and performance of MR CDC dampers for the vehicles. In addition, an operating point on the B-H curve, the magnetization according to the variation in the annular gap, the pole piece width and the density of MR fluid are studied to design the optimal piston head within the restrained dimension range.
Autonomous Tracking Control of Intelligent Vehicle using GPS Information
Chung, Byeung-Mook ; Seok, Jin-Woo ; Cho, Che-Seung ; Lee, Jae-Won ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 58~66
In the development of intelligent vehicles, path tracking of unmanned vehicle is a basis of autonomous driving and automatic navigation. It is very important to find the exact position of a vehicle for the path tracking, and it is possible to get the position information from GPS. However the information of GPS is not the current position but the past position because a vehicle is moving and GPS has a time delay. In this paper, therefore, the moving distance of a vehicle is estimated using a direction sensor and a velocity sensor to compensate the position error of GPS. In the steering control, optimal fuzzy rules for the path tracking can be found through the simulation of Simulink. Real driving experiments show the fuzzy rules are good for the steering control and the position error of GPS is well compensated by the proposed estimation method.
Intelligent PID Controller Design Using Root-Locus Analysis for Systems with Parameter Uncertainties
Shin, Young-Joo ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 67~76
In this research, a simple technique for designing PID controller, which guarantees robust stability for two-mass systems with parameter uncertainties as well as rigid-body behavior and zero steady-state error,is described. As well, such a PID controller is designed to mate two important frequencies, at which the given system is excited, very close so that an appropriate reference profile generated by using command shaping techniques can cover those two frequencies. Root-locus analysis. which shows traces of closed-loop poles for the given system, is used to design this PID controller. Finally, feedforward controller is added to improve tracking performance of the closed-loop system. Simulation for a system with a flexible mode and parameter uncertainties is executed to prove the feasibility of this technique.
Fatigue Strength Evaluation of Carbody and Bogie Frame for the Light Rail Transit System
Lee, Eun-Chul ; Lee, Joon-Seong ; Choi, Yoon-Jong ; Lee, Jung-Hwan ; Suh, Myung-Won ; Lee, Ho-Yong ; Lee, Yang-Chang ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 77~83
In terms of saving costs, energy and materials, the weight of cars has been gradually reduced by optimizing design of structure, which also gives us good performance. In compliance with this, it should satisfy the lifetime of cars for 25 years under the operation. The purpose of this study is to evaluate the strength of fatigue using date from strain gauges attached carbody and bogie frame. This dynamic stress can be evaluated using S-N curve based on stress amplitude. Modified S-N curve by CORTON-DOLAN is used for more conservative and substantial evaluation. In addition, !he loadings itself of carbody and bogie frame are considered by calculating the rate of the differences which are occurred between empty car and fuiiy occupied car with passengers. Rainflow cycle counting method is applied to arrange the stress data for the modified S-N curve to predict lifetime of the materials. Conclusively the cumulative damages are not only calculated by Miner's Rule, but the safety factors are also determined by Goodman diagram.
Stress Distribution in the Vicinity of a Crack Tip in a Plate under Tensile Load Using Displacement Data of Finite Element Method
Baek, Tae-Hyun ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 84~91
Due to the complexity of the engineering problems, it is difficult to obtain directly the stress field around the crack tip by theoretical derivation. In the paper, the hybrid method is employed to calculate full-field stress around the crack tip in uni-axially leaded finite width tensile plate, using the displacement data of given points calculated by finite element method as input data. The method uses complex variable formulations involving conformal mappings and analytical continuity. In order to accurately compare calculated fringes with experimental ones, both actual and reconstructed photoelastic fringe patterns are two times multiplied and sharpened by digital image processing. Reconstructed fringes by hybrid method are quite comparable to actual fringes. The experimental results indicate that Mode I stress intensity factor analyzed by the hybrid method are accurate within a few percent compared with ones obtained by empirical equation and finite element analysis.
The Study on Designing and Making Power Standing Wheelchair
Jo, Jang-Hyen ; Song, Yo-Chang ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 92~98
This paper is concerned with the designing and making power standing wheelchair. This wheelchair is studied based on the mechanical and electrical engineering concepts and theories. The mechanical theories are composed of statics and dynamics knowledges that are related with moving and standing position. Basically the static and dynamic stability is the most important element in designing and making the real size model. The linear actuator is used in the standing mechanism and the joystick controlled by hand is attached on the arm rest. The real size model is made and also investigated through the design specifications by test drive. Finally, this paper proves the possibility of commerical production of power standing wheelchair.
Design of 5kWh Flywheel Energy Storage System to Improve Dynamics
Park, Cheol-Hoon ; Choi, Sang-Kyu ; Ham, Sang-Yong ; Lee, Sung-Whee ; Yun, Dong-Won ; Han, Young-Hee ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 99~106
5kWh FESS(Flywheel Energy Storage System) using AMB(Active Magnetic Bearing) has been under development and 1st trial system has been finished and run the operating test. Unfortunately, the test result was not satisfactory because FESS could increase the rotational speed up to 9,000 rpm only although the target rotational speed is 18,000rpm. It's because 1st bending mode frequency of flywheel shaft was too low and imbalance response was too big. To achieve the target speed, 1st bending mode and imbalance response must be improved and the whole FESS needed to be designed again. This paper presents the newly designed FESS and what has been changed from the 1st trial FESS to improve 1st bending mode and imbalance response. The experimental results to see how much 1st bending mode frequency was improved are presented, too.
Dynamic Analysis and Experiments of High Impulsive Force Device with Isolation System
Park, Moon-Sun ; Kang, Tae-Ho ; Byun, Young-Seop ; Song, Joon-Beom ; Ku, Tae-Wan ; Kang, Beom-Soo ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 107~114
The aim of this study is to obtain the useful design guideline for high impulsive force device with an isolation system by the analytic approach of dynamics characteristics. In this study, the high impulsive force system was modeled and analyzed in view of multi-body dynamics, and verified the modeling and analysis result by the experiment of the high impulsive force device. Additionally, the dynamic analysis was performed for the isolation system with the selected coefficients of elastic spring and damper selected. Experimental result for the high impulsive force device with the isolation system was compared and analyzed. From the result, it was confirmed that the design guideline for the isolation system of the high impulsive force device was useful.
Investigation of Cogging Effect in Bisymmetric Dual Iron Core Linear Motor Stage
Oh, Jeong-Seok ; Park, Chun-Hong ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 115~121
This paper presents bisymmetric dual iron core lineal motor stage for heavy-duty high precision applications such as large area micro-grooving machines or high precision roll die machines. In this stage, two iron core linear motors are installed in laterally symmetric way to cancel out the attractive forces. Main focus was given to analyzing the effect of cogging force and moment for two different layouts, which are symmetric and half-pitch shifted ones. Experimental results showed that the symmetric layout is more adequate for high precision applications because of its clear moment cancellation effect. It was also verified that the effect of the residual cogging moment can be suppressed further by increasing the bearing stiffness. One problem of the symmetric layout is added cogging force which hinders smooth motion, but its effect was relatively small compared with that of moment cancellation.
Command Generation Method for High-Speed and Precise Positioning of Positioning Stage
Jang, Joon-Won ; Park, Sang-Won ; Hong, Seong-Wook ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 122~129
This paper deals with precise positioning of a high-speed positioning stage without inducing residual vibration by using an input shaping technique. Input shaping is well known to be a very effective tool for suppressing the residual vibration of flexible structures. However, the ordinary input shaping for positioning stages is designated mostly for velocity regulation, not for the residual vibration at the target position. The main difficulties in implementing input shaping along with precise positioning are the time delay caused by the servo system characteristics and the s-curve feature often employed in some motor controllers. This paper analyzes the dynamic responses of a single-mode-dominate stage system subjected to input shaping. A theoretical model is developed io investigate the nature of system. In order to overcome the difficulty, this paper proposes an improved input shaper based on modified command profile generation. The proposed method is proved effective through experiments and simulations.
Chaos Analysis of Major Joint Motions for Women during Treadmill Walking
Kim, Min-Kyoung ; Son, Kwon ; Park, Jung-Hong ; Seo, Kuk-Woong ; Park, Young-Hoon ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 130~136
The purpose of this study was to investigate chaotic characteristics of major joint motions during treadmill walking. Gait experiments were carried out for 20 healthy young women. The subjects were asked to walk on a treadmill at their own natural speeds. The chaos analysis was used to quantify nonlinear motions of eleven major joints of each woman. The joints analyzed included the neck and the right and left shoulders, elbows, hips, knees and ankles. The recorded gait patterns were digitized and then coordinated by motion analysis software. Lyapunov exponent for every joint was calculated to evaluate joint characteristics from a state space created by time series and its embedding dimension. This study shows that differences in joint motion were statistically significant.
The Role of Synovial Fluid and Hyaluronan in the Frictional Response of Bovine Articular Cartilage
Park, Seong-Hun ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 137~143
The objective of this study was to characterize the role of synovial fluid and hyaluronan in the frictional response of bovine articular cartilage. Seven cylindrical cartilage specimens were harvested from three fresh bovine humoral heads (4-6 months old). Reciprocal sliding motion (1mm/s) was provided by a custom-made friction testing apparatus with a normal load of 22.3 N. From the measured time-dependent normal and frictional forces, the minimum and maximum frictional coefficients were calculated. Synovial fluid reduced the minimum frictional coefficient by
% and maximum frictional coefficient by
, while the reduction of the minimum and maximum frictional coefficients with hyaluronan was
, respectively. To the best of our knowledge, this experimental study investigates the first such comparisons of frictional response of articular cartilage with and without synovial fluid and hyaluronan, and provides significant insights into their role in the articular cartilage friction and lubrication.
Degree of Filling Balance according to Runner Shapes in Injection Mold
Han, Dong-Yeop ; Jeong, Yeong-Deug ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 10, 2008, Pages 144~149
Configuration of filling imbalance which is originated from imbalanced share rate of melt on runner is changed by runner layout, runner shape, material property, injection pressure, injection speed, melt temperature and mold temperature. In this paper, we conducted a study of runner layout and shape that are main factors of filling imbalance. Other factors such as the sharp corner effect and the groove corner effect are recently released were also considered. The results of study are showed that filling rate of between inside and outside cavity was influenced on shape of runner. Especially, this study suggests a new runner system for filling balance by adapting the two effects of unary branch type runner at multi cavity mold and theoretical investigated flow in the sharp corner type runner.