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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 19, Issue 12 - Dec 2002
Volume 19, Issue 11 - Nov 2002
Volume 19, Issue 10 - Oct 2002
Volume 19, Issue 9 - Sep 2002
Volume 19, Issue 8 - Aug 2002
Volume 19, Issue 7 - Jul 2002
Volume 19, Issue 6 - Jun 2002
Volume 19, Issue 5 - May 2002
Volume 19, Issue 4 - Apr 2002
Volume 19, Issue 3 - Mar 2002
Volume 19, Issue 2 - Feb 2002
Volume 19, Issue 1 - Jan 2002
Selecting the target year
Thermal Deformation Characteristics and Compensation of′ High Speed Spindle Unit
Lee, Chan-Hong ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 7~12
Thermal Deformation Characteristics and Compensation of High Speed Feed Mechanism
Eun, In-Ung ; Lee, Choon-Man ; Chung, Won-Jee ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 13~18
Modeling Methods for Thermal Errors of Machine Tool
Lee, Jae-Jong ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 19~24
Thermal Response of Machine-tool Structures and Improvement
Kim, Tae-Weon ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 25~28
Hemming Process Design of the Permalloy Shielding Can for the Stiffness and Shape Accuracy
Lee, Sun-Bong ; Kim, Dong-Hwan ; Kim, Byung-Min ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 29~35
This study shows the process design and forming analysis of permalloy shielding can that support the automobile multi-display parts to indicate the accurate information of car. This study is particularly important, since the accuracy of permalloy shielding can is known to affect the magnetic properties such as coercivity and permeability quite sensitively. The objective functions are defects such as hemming wind, hemming length, hemming wrap and tightness in prehemming process. The pre-hemming angle is considered as design parameter. The commercial finite element program PAM-STAMP™ was used to simulate the pre-hemming and hemming process. The ANN (Artificial Neural Network) has been implemented for minimizing of objective function and for investigating effect of punch angle relevant to the pre-hemming process. The results of analysis to validate the proposed design method are presented.
Building of Occupancy Grid Map of an Autonomous Mobile Robot Based on Stereo Vision
Kim, Jong-Hyup ; Choi, Chang-Hyuk ; Song, Jae-Bok ; Park, Sung-Kee ; Kim, Mun-Sang ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 36~42
This paper presents the way of building an occupancy grid map which a mobile robot needs to autonomously navigate in the unknown environment. A disparity map resulting from stereo matching can be converted into the 2D distance information. If the stereo matching has some errors, however, the subsequent map becomes unreliable. In this paper, a new morphological filter is proposed to reject 'spikes' of the disparity map due to stereo mismatch by considering the fact that these spikes occur locally. The new method has advantages that it is simpler and more easily realized than existing similar algorithms. Several occupancy grid maps based on stereo vision using the proposed algorithm have been built and compared with the actual distance information to verify the validity of the proposed method.
Plastic Flow Direction and Strength Evaluation of Dissimilar Fiction Bonding Interface Joints
Oh, Jung-Kuk ; Sung, Back-Sub ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 43~50
Friction welding has many merits such as energy efficiency, simple processing, etc butt difficult to obtain good weld at the welded interface and heat affected zone. To date, the continuum mechanics and fracture mechanics are utilized to analyse stresses at the interface and propagation of cracks. In this study. STS304 and SM15C are selected because they can be differentiated distinctively from metallic point of view and crack can be observed easily. It is ovserved during friction welding that STS304, rotary part is hatter than SH15C, fixed part. The last fracture occurs around the center because the surface of fatigue fracture has smooth regions, due to the separation phenomenon in plastic flows layers and striation dimple pattern.
Dynamic Optimization of Multi-body Systems
Lee, Jong-Nyun ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 51~55
This paper presents a systematic methodology and formulation for determining optimal strategies of multi-body dynamic systems, which is based on multi-body dynamics, design sensitivity, and optimization techniques, and is applicable to a wide variety of mechanical systems. The particular application discussed in this paper considers a vehicle model with four-wheel steeling capability, and the presented methodology determines an optimal steering angle ratio strategy for the vehicle. It is shown that such a strategy can improve the ride stability of the vehicle, during a variety of maneuvers, when compared against similar strategies obtained from linear and simplified vehicle models.
Proposal and Theoretical Verification on Motion Error Analysis Method of Hydrostatic Tables Using Transfer Function
Park, Chun-Hong ; Oh, Yoon-Jin ; Lee, Chan-Hong ; Hong, Joon-Hee ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 56~63
A new model utilizing a transfer function is introduced in the present paper for analizing motion errors of hydrostatic tables. Relationship between film reaction force in a single hydrostatic pad and form error of a guide rail is derived at various spacial frequencies by finite element analysis, and it is expressed as a transfer function. This transfer function clarifies so called averaging effect of the oil film quantitively. For example, it is found that the amplitide of the film reaction farce is reduced as the spacial frequency increases or relative width of the pocket is reduced. Motion errors of a multiple pad table is estimated from transfer function, geomatric relationship between each pads and form errors of a guide rail, which is named as Transfer Function Method(TFM). Calculated motion errors by TFM show good agreement with motion errors calculated by Multi Pad Method, which is considered entire table as an analysis object. From the results, it is confirmed that the proposed TFM is very effective to analyze the motion errors of hydrostatic tables.
Experimental Verification on Motion Error Analysis Method of Hydrostatic Tables Using Transfer Function
Oh, Yoon-Jin ; Park, Chun-Hong ; Lee, Chan-Hong ; Hong, Joon-Hee ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 64~71
A new model utilizing a transfer function was proposed in the previous paper fur analizing motion errors of hydrostatic tables. Validity of the proposed method was theoretically verified as the calculated motion errors were compared with the results by conventional multi pad method. In this paper, relationship between form error of rail and motion errors of hydrostatic table is analized theoretically in order to comprehand so-called ‘averaging effect of oil film’. Experiments on the motion errors of hydrostatic table is conducted with 3 different rails, and the results are compared with the results calculated by Transfer Function Method. The results show good agreement. From the results, it is verified that TFM is very effective to analize the motion errors of hydrostatic table.
Methodology for Estimation of Assembly Time and Evaluation of Asseblability
Mok, Hak-Soo ; Cho, Jong-Rae ; Kang, Young-Hun ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 72~80
DFA (Design for assembly) is a design philosophy for improving product designs for simpler or less costly assembly operations. This paper proposes a new DFA methodology that can estimate the standard assembly time and evaluate the assemblablity of parts. We select some determining and influencing factors related with assembly process, and estimate the assembly time using motion analysis. By the levels of the determining and influencing factors, the assemblability is evaluated, and finally, the tables that include the time and score of assembly is suggested.
Stress Intensity Factor for an Interface Crack of a Piezoelectric Medium Bonded Between an Elastic Layer and a Half-Space
Jeong, Kyoung-Moon ; Lim, Chun-Ki ; Beom, Hyeon-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 81~88
An interface crack of a piezoelectric medium bonded between an elastic layer and a half-space is analyzed using the theory of linear piezoelectricity. Both out-of-plane mechanical and in-plane electrical loads are applied to the piezoelectric laminate. By the use of courier transforms, the mixed boundary value problem is reduced to a singular integral equation which is solved numerically to determine the stress intensity factors. Numerical analyses for various material combinations are performed and the results are discussed.
Simultaneous 3D Machining with Real-Time NURBS Interpolation
Hong, Won-Pyo ; Yang, Min-Yang ; Lee, Eung-Ki ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 89~94
Increasing demands on precision machining using CNC machines have necessitated that the tool to move with a position error as small as possible in 3-dimensional (3D) space. This paper presents the simultaneous 3D machining with a retrofitted PC-NC milling machine. To achieve the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non-Uniform Rational B-Spline(NURBS) curve is used. With this accurate and efficient algorithm for the generation of complex. 3D shapes, a real-time NURBS interpolator was developed using a PC and the simultaneous 3D machining is accomplished.
A Study on the Determination of Grinding Wheel Life and Dressing Time Using AE Sensor
Jun, Kil-Jae ; Lee, Sang-Tae ; Kim, Nam-Kyung ; Jung, Yoon-Gyo ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 95~102
The grinding operation is an important machining process for machining of final surface. However, grinding process has inevitable troubles such as loading and glazing for grinding wheel. It is, therefore, an essential research theme to determine the wheel life and the dressing time for efficient grinding. In this study, AE signals (AEavg) generated in the grinding operation were measured and the dressing time was determined from the analysis of the AEavg value. To verify the propriety of the obtained result, the AE signals measured on the grinding and the dressing operation were compared with the grinding force signals and the dressing force which were measured at same time. From the obtained result, it was confirmed that the determination of the wheel life and the dressing tilde by the AE measurement technique proposed in this study can be practically used.
Frequency Response Characteristics of Two-Staged Gear Reduction Servo System According to the Backlash Contribution Ratio Variation of Each Gear Reduction Stage
Baek, Joo-Hyun ; Hong, Sung-Min ; Yang, Tae-Suk ; Kim, Soo-Hyun ; Kwak, Yoon-Keun ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 103~109
The paper investigates the change of frequency response characteristics on two-stage gear reduction servo system according to the variation of backlash amount of each gear reduction stage, under the condition that the backlash of total system is constant. It is shown that the frequency response characteristics of the system heavily depend on the contribution ratio which is defined as a ratio of the first backlash amount to the total backlash. It is also found that there is an optimal backlash combination to maximize the bandwidth of two-stage gear reduction servo system when the allowable total backlash is determined.
A study on Optimization of the Design Variables of Linear Motor Using Genetic Algorithm
Joo, Sang-Hyun ; Jung, Jae-Han ; Lee, Sang-Ryong ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 110~117
This paper proposes a optimization of the design variables of linear motor for the improvement of thrust. Especially, this paper treats the shoe, which can be good to flow of a magnetic flux in linear motor. Firstly, this paper uses a space harmonic analysis method(SHAM) based on Fourier series, for analyzing the characteristics of core type linear motor, including slot structure and shoe. And compare the magnetic flux densities of linear motor at air gap with the results of the SHAM and the Finite Element Method(FEM). Secondly, this paper uses a genetic algorithm, which is good to find the global solutions. The design variables are the pole pitch of magnet, the pitch of slot, the height of slot, the width of shoe and the width of magnet. The maximum thrust with optimum design variables is about 247 N which is improved about 16%.
Generalized Kinematics Modeling of Wheeled Mobile Robots
Shin, Dong-Hun ; Park, Kyung-Hoon ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 118~125
The previous kinematic analysis of wheeled mobile robots(WMRs) is performed in an ad-hoc manner, while those of the robot manipulators are done in a consistent way using the coordinate system assignment and the homogeneous transformation matrix. This paper shows why the method for the robot manipulators cannot be used directly to the WMRs and proposes the method for the WMRs, which contains modeling the wheel with the Sheth-Uicker notation and the homogeneous transformation. The proposed method enable us to model the velocity kinematics of the WMRs in a consistent way. As an implementation of the proposed method, the Jacobian matrices were obtained for conventional steered wheel and non-steered wheel respectively and the forward and inverse velocity kinematic solutions were calculated fur a tricycle typed WMR. We hope that our proposed method comes to hold an equivalent roles for WMRs, as that of the manipulators does for the robot manipulators.
A Study on Shaft Alignment of the Rotating Machinery by Using Strain Gages
Kim, Koung-Suk ; Jang, Wan-Shik ; Na, Sang-Soo ; Jung, Hyun-Chul ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 126~132
Misaligned shafts of the rotating machinery have caused noise, vibration. bearing failures, and stress concentration of coupling parts which decrease the efficiency and life of shaft systems. Therefore the proper shaft alignment of those system should be monitored continuously in dynamic condition. To solve these problems under dynamic condition a telemetry system is used. In this study, the condition of the least bending moment which is known by analyzing the structure and stress induced by misalignment is found. After the shaft is aligned by dial gage, a telemetry system with strain gages is installed on shaft. The relationship between bearing displacement and moment of coupling part influenced by misalignment is investigated. The moment derived from two shaft strain at the nearby coupling is measured. The bending strain is measured 5 times for average in static state as well as in dynamic state with 100∼700 rpm.
Machinability Evaluation according to Variation of Endmill Shape for High Speed Machining
Kang, Myung-Chang ; Kim, Jeong-Suk ; Lee, Deuk-Woo ; Kim, Kwang-Ho ; Ha, Dong-Geun ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 133~138
The technique of high speed machining is widely studied in machining fields, because the high efficiency and accuracy in machining can be obtained in high speed machining. Unfortunately the development of tool fur high speed machining in not close behind that of machine tool. In this study, 10 types flat endmill is prepared for obtaining data according to tool shape. Especially, we concentrated in helix angle, number of cutting edge and rake angle. Cutting condition is selected for several experiments and measuring cutting farce, tool life, tool wear and chip shape according to cutting length. 3-axis cutting farces are acquired from the tool dynamometer with high natural frequency, as the conventional tool dynamometer (9257B, Kistler) has cannot measure the state of high frequency force. Particularly, we found out that the axial cutting force waveform has a good relation with tool wear features. And flow is interrupted at the beginning of cutting by the decrease of rake angle. By above results. it is suggested the endmill tool with 45
helix angle, 6 cutting edge and -15
rake angle is suitable for high speed machining.
Analysis of the Motion Errors in Linear Motion Guide
Kim, Kyung-Ho ; Park, Chun-Hong ; Lee, Hu-Sang ; Kim, Seung-Woo ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 139~148
Motion errors of linear motion guideway are analyzed theoretically in this paper. For the analysis, an new algorithm predicting motion errors of bearing and guideway is proposed using the Hertz's elastic deformation theory. Accuracy averaging effect can be calculated quantitatively by analyzing relationship between motion errors of guideway and spatial frequency of rail form error. Influences of design parameters on the motion errors including the number of balls, preload, ball diameter, bearing length and the number of bearings are analyzed. As it is difficult to measure the rail form error, experimental results are compared with results analyzed by the equivalent analysis method which evaluate the motion errors of guideway using the measured errors of bearing. From the experimental results, it is confirmed that the proposed analysis method it effective lo analyze the motion errors of linear motion bearing and guideway.
A Study on ILD(Interlayer Dielectric) Planarization of Wafer by DHF
Kim, Do-Youne ; Kim, Hyoung-Jae ; Jeong, Hae-Do ; Lee, Eun-Sang ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 149~158
Recently, the minimum line width shows a tendency to decrease and the multi-level increases in semiconductor. Therefore, a planarization technique is needed and chemical mechanical polishing(CMP) is considered as one of the most suitable process. CMP accomplishes a high polishing performance and a global planarization of high quality. However there are several defects in CMF, such as micro-scratches, abrasive contaminations and non-uniformity of polished wafer edges. Wet etching process including spin-etching can eliminate the defects of CMP. It uses abrasive-free chemical solution instead of slurry. On this study, ILD(Interlayer-Dielectric) was removed by CMP and wet etching process using DHF(Diluted HF) in order to investigate the possibility of planrization by wet etching mechanism. In the thin film wafer, the results were evaluated from the viewpoint of material removal rate(MRR) and within wafer non-uniformity(WIWNU). And the pattern step heights were also compared for the purpose of planarity characterization of the patterned wafer. Moreover, Chemical polishing process which is the wet etching process with mechanical energy was introduced and evaluated for examining the characteristics of planarization.
Remote Measuring System for Automobile′s ECU Self Diagnostic Signal
Jeong, Jin-Ho ; Yun, Yeo-Heung ; Lee, Young-Choon ; Kwon, Tae-Kyu ; Lee, Seong-Cheol ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 159~167
In this paper. we present a new method for monitoring of ECU's self diagnostic signals of vehicle without wire. In order to measure the ECU's self diagnostic signals, the interfaced circuit is designed to communicate ECU and designed terminal according to the IOS, SAE regulation of communication protocol standard. Micro-processor 80C196KC is used for communicating ECU's self diagnositc signals and the results are sent to the wireless terminal and PC monitoring system. Wireless terminal is also developed by 80C196KC, LCD, RF module, and keypad. The command from the keypad is sent to ECU through RF module and the result show on the Graphic LCD in real time. Software on PC is developed to monitor the ECU's self diagnostic signals using the Visual C++ complier in which RS232 port is programmed by half duplex method. The algorithms for measuring the ECU's self diagnostic signals are verified to monitor both ECU and portable terminal state. At the same time, the information to fix the vehicle's problem can be shown on the developed software. The possibility for remote measurement of ECU self diagnostic signal is verified through the developed systems and algorithms.
An Investigation into the State-Space Model for a Hydraulic Attenuator
Lee, Jae-Cheon ;
Journal of the Korean Society for Precision Engineering, volume 19, issue 5, 2002, Pages 168~175
The hydraulic acoustic attenuator fur an automotive active suspension system is so highly nonlinear and of high order that the analysis in time-domain has been performed quite little. In this paper, a state-space representation of the dynamics for a hydraulic attenuator was presented utilizing the electrical analogy. And the results of experiment were compared with those of simulation to validate the state-space model proposed. The comparison revealed that the state-space model proposed is practically applicable to estimate the dynamic responses of the hydraulic attenuator in time-domain.