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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 16, Issue 12 - Dec 1999
Volume 16, Issue 11 - Nov 1999
Volume 16, Issue 10 - Oct 1999
Volume 16, Issue 9 - Sep 1999
Volume 16, Issue 5 - May 1999
Volume 16, Issue 4 - Apr 1999
Volume 16, Issue 3 - Mar 1999
Volume 16, Issue 2 - Feb 1999
Volume 16, Issue 8 - Jan 1999
Volume 16, Issue 7 - Jan 1999
Volume 16, Issue 6 - Jan 1999
Volume 16, Issue 1 - Jan 1999
Selecting the target year
Strain Analysis of a Six Axis Force-Torque Sensor Using Cross-Shaped Elastic Structure with Circular Holes
Kim, Joo-Yong ; Kang, Chul-Goo ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 5~14
The necessity of six axis force-torque sensors is well recognized in the fields of automatic fine assembly, deburring polishing, and automatic fish processing using robotic manipulators. The paper proposes a simple and compact elastic structure of the force-torque sensor which senses externally applied three force and three torque components. Rough surface strain distribution of the elastic structure is examined analytically, and then more accurate surface strain are obtained from finite element analysis. The compliance matrix which is a linear relationship between force components and strain measurements is obtained for the proposed sensor. Some basic principles of measuring 3 force and torque components are also presented.
A Study on Development and Control of Micro Active Catheter Actuator
Lee, Jang-Moo ; Kim, Jong-Hyun ; Lee, Sang-Won ; Park, Jun-Hyung ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 15~22
This paper demonstrates the feasibility of Shape Memory Alloy (SMA) actuators in controlling the motion of micro active catheter. The dynamic behavior of SMA is obtained by several experiments for the design of the controller. With the control parameters obtained in experiments, temperature feedback control algorithm is proposed and realized. The prototype of micro active catheter is fabricated, and its control performance which uses the designed controller is investigated. The results obtained show the potential of the SMA as viable means for actuating the micro active catheter.
Radial Performances of Spiral-Grooved Spherical Air Bearings
Park, Keun-Hyung ; Choi, Jeong-Hwan ; Choi, Woo-Chon ; Kim, Kwon-Hee ; Woo, Ki-Myung ; Kim, Seung-Kon ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 23~30
This paper investigates the radial performance of self-acting spiral-grooved air bearing, used to support small high-speed rotating bodies. Repeatable runout, nonrepeatable runout, stiffness and supporting load are selected as the performance. The clearance between rotor and stator, the stator groove depth, and the rotating speed are chosen as three main parameters affecting the performances. Force application and displacement measurement are done in a noncontact manner, in order not to disturb operation: electromagnetic force is applied to the rotor and gap sensors are used to measure the displacement of the rotor. Experimental results show that repeatable runout decreases as speed, groove depth and clearance decrease. Nonrepeatable runout decreases as clearance decreases, and it has a minimum value at
of grove depth and a maximum value at speed of 18.000rpm. Stiffness increases as speed increases and clearance decreases, and has a maximum value around
of groove depth. The relationship between force and displacement is linear for small displacement, but becomes nonlinear for large displacement. Supporting load is linearly proportional to the stiffness, and it is a maximum value around
A Study on Strain Relief in a Square Cup Drawing
Kim, Jin-Moo ; You, Ho-Young ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 31~38
Square cups have been drawn to 20mm~60mm in depth and displacements and strains have been analysed by FEM and experiment. Displacements and strains on the corner flange of square cups have been compared with those of cylindrical cups. The results have shown that shear strains take place on corner flanges of square cups, it is necessary to adopt effective strain for comparing of stains and the effective strains on the corner flange in square cups are smaller than those in cylindrical ones.
Position and Orientation Recognition for Adjusting Electronic Tuners
Yang, Jae-Ho ; Kong, Young-June ; Lee, Moon-Kyu ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 39~49
This paper describes the development of a vision-aided position and orientation recognition system for automatically adjusting electronic tuners which control the waveform by rotating variable resisters. The position and orientation recognition system estimates the center and the angle of the tuner grooves so that the main controller may correct the difference from the ideal position and thereby manipulate the variable resisters automatically. In this paper a robust algorithm is suggested which estimates the center and the angle of the tuner grooves fast and precisly from the source image with lighting variance and video noise. In the algorithm morphological filtering, 8-chain coding, and invariant moments are sequentially used to figure out image segments concerned. The performance of the proposed system was evaluated using a set of real specimens. The results indicate the system works well enough to be used practically in real manufacturing lines. If the system adopts a high speed frame grabber which enables real time image processing, it can also be applied to positioning of robot manipulators as well as automated PCB adjusters.
An Analysis of the Effect of a Variant Drain Orifice Damping on an Electrohydraulic Servovalve Flapper-Nozzle Stage
Lee, Jae-Cheon ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 50~59
The effect of a variant drain orifice damping on the characteristics of a servovalve flapper-nozzle stage is analyzed. Steady-state characteristics of flapper-nozzle stage and the linearized dynamics of flapper-nozzle assembly with a spool valve show that the variant drain orifice damping could improve such null performance characteristics as null pressure sensitivity and linearity of gain function. Generalized design criterion and a sufficient condition for servovalve stability are also established.
Selective Removal of Mask by Mechanical Cutting for Micro-patterning of Silicon
Jin, Won-Hyeog ; Kim, Dae-Eun ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 60~67
Micro-fabrication techniques such as lithography and LIGA processes usually require large investment and are suitable for mass production. Therefore, there is a need for a new micro-fabrication technique that is flexible and more cost effective. In this paper a novel, economical and flexible method of producing micro-pattern on silicon wafer is presented. This method relies on selective removal of mask by mechanical cutting. Then micro-pattern is produced by chemical etching. V-shaped grooved of about 3
wide and 2
deep has been made on
coated silicon wafer with this method. This method may be utilized for making microstructures in MEMS application at low cost.
Recognition and Machining for Large 2D Object using Robot Vision
Cho, Che-Seung ; Chung, Byeong-Mook ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 68~73
Generally, most of machining processes are done according to the dimention of the draft made by CAD. However, there are many cases that a sample is given without the draft because of the simplicity of the shape in the machining of 2D objects. To cut the same shape as the given sample, this paper proposes the method to extract the geometric information about a large sample using the robot vision and to draw the demensional draft for the machining. Because the resolution of one frame in the vision system is too low, it is necessary to set up a camera according to the desired resolution and to capture the image moving along the contour. And the overall outline can be compounded of the sequentially captured images. In the experiment, we compared the product after the cutting with the original sample and found that the size of two objects was coincided within the allowed error bound.
Fabrication of Optical Micro-Encoder Chips for Sub-Micron Displacement Measurements
Kim, Keun-Joo ; Kim, Yun-Goo ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 74~81
The integrated chip of optical micro-encoder was fabricated and the feasibility as displacement measurement device was confirmed. The geometry of micro-encoder was designed to utilize the optical interference effect on the second order of diffracted beams. The hybrid-type micro-encoder consisted with light emitting diode, photodiode, polyimide wave-guide and micro-lens provides stable micro-encoding results for high speed displacements. The measurement shows the resolution of displacement of 1.00 +/- 0.02
for the grating with scale pitch of 2.0
An Experimental Study on the Bending Process of Stainless Steel Sheets
Kim, Ho-Yoon ; Hwang, Bum-Cheal ; Bae, Won-Byong ; Kang, Chung-Gil ; Byun, Cheon-Deock ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 82~86
An experimental study has been carried out to reduce bending load, surface roughness and springback in bending process of stainless steel sheets. A U-bending test has been performed to investigate appropriate process parameters for getting better surfaces and accurate dimensions of stainless steel products. In the test, selected process parameters are die material, lubricant, and die clearance. Die materials used in the test are STD11(HRC60), STD11(TiCN), and AMPCO. From the test results, we can suggest that AMPCO dies are most suitable for reducing bending load and surface roughness of stainless steel sheets. And STD11 dies are favorable for avoiding spring-back in the stainless steel sheet-bending.
An Automated CAD System for Press Die Design in Cold Forging of Axisymmetric Parts
Kim, Jong-Ho ; Ryu, Ho-Yeun ; Hong, Ki-Gon ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 87~94
The automated die design program is developed for cold forging of axisymmetric parts which are mainly produced by forward extrusion, backward extrusion, composite extrusion and upsetting. For this study, firstly classification of forged parts and investigation of die construction type usually employed in forging industry are carried out and the most proper type from several kinds of die construction is proposed as a standardized one. Based on the die design rules summarized in the references such as handbooks, technical papers, monthly journals, etc. the automated die design program was made using AutoLISP language available in AutoCAD software of personal computer. This program interactively runs for only input data, for example, forging process, shape of forged parts, type of punch, split of die insert and design of shrinkage rings and then displays details of drawings necessary to make a forging die. When a variety of forging processes and forged parts are tested to examine the validity of this program, it was confirmed to give good results applicable to the forging die design in press shop.
Tracking Control Design for Actuating Fin in Underwater Vehicle Under Uncertain Load Torques
Kim, Dong-Hwan ; Lee, Kyo-Il ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 95~103
Chatter Prediction in Endmilling Using Dynamic Cutting Force Modeling
Hwang , Cheol-Hyun ; Cho, Dong-Woo ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 104~115
Cutting process, in general, is a closed-loop system consisting of structural dynamics and cutting dynamics, with the cutting forces and the relative displacements between tool and workpiece being the associated variables. There have been a number of works on modeling the cutting process of endmilling, most of which assumed that either one of the tool or workpiece be negligible in tis displacement. In this paper, the relative displacement between tool and workpiece was considered. The proposed model used experimental modal analysis for structural dynamics and an instantaneous uncut chip thickness model for cutting dynamics. Simulation of the model, a time varying cutting system, was performed using 4th order Runge-Kutta method. Subsequent simulation results were utilized to predict chatter over a variety of experiments in slotting operation, showing good agreement.
A Simple Noise Reduction Method using SVD(Singular Value Decomposition)
Shin, Ki-Hong ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 116~122
Characteristics of Tool Deflection of Ball-end Mill Cutter in Pencil Cutting of the Corner
Wang, Duck-Hyun ; Yun, Kyung-Suk ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 123~129
Ball-end milling process is widely used in the die and mold manufacturing because of suitable one for the machining of free-form surface. During the process, the pencil cutting operation can be adopted before finish cut to eliminate overload in uncut area caused by large diameter of ball-end mill. The ball-end mill cutter for the pencil cutting is easily deflected by cutting force due to the long and thin shape, and the tool deflection in pencil cutting is one of the main reason of the machining errors in a free-form surface. The purpose of this study is to find the characteristics of deflected cutter trajectory by constructing measurement system with eddy-current sensor. It was found that the severe reduction of corner radius produced the overcut during the plane cutting. Up cutting method induced the overcut both plane and slope cutting, but down cutting one induced the undercut. From the experiments, down cutting with upward cutting path can generate the small undercut surface.
Exploration of Curvature of Three Dimensional Convex Object by Active Touch of Robot Hand
Choi, Hyouk-Ryeol ; Kim, Jin-Ho ; Oh, Sang-Rok ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 130~137
In this paper we propose a method of determining the local curvature of a three dimensional convex object using the force and torque information obtained from the active touch of a robot hand. A technique for estimating two dimensional curvature of a convex object are introduced and the way of computing the three dimensional curvature from the two dimensional vurvatures is presented. Also, we develop an experimental system consisting of a finger and verify the effectiveness of the proposed method experimentally.
Stress Evaluation by Measuring Ultrasonic Velocity
Lee, Bum-Sung ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 138~144
Longitudinal wave and shear wave velocity changes of PMMA Polymer meterial under the the unidirection load were measured. The Third-order elastic modulus and acousto-elastic modulus of PMMA are obtained. The theoretical and experemental values of the velocity change of each wave by stress are compared each other and the validity of theoretical expression is examinated.
A Study on Roughness Measurement of Polished Surfaces Using Reflected Laser Beam Image
Shen, Yun-Feng ; Lim, Han-Seok ; Kim, Hwa-Young ; Ahn , Jung-Hwan ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 145~152
This paper presents the principle and experimental results of a non-contact surface roughness measurement by means of screen projected pattern of lase beam reflected from a polished surface. In the reflected laser beam pattern especially from a fine surface like ground or polished one, light intensity varies from the center fo the image to its boundary as the Gaussian distribution. The standard deviation of a light intensity distribution is assumed to be a good non-contact estimator for measuring the surface roughnes, because the light reflectivity is known to be well related with the surface roughness. This method doesn't need to discriminate between the specularly reflected light and the diffusely reflected one, whereas the scattered laser intensity method must do. Nor it needs to adjust the change of light intensity caused by environmental lights or specimen materials. Reflected laser beam pattern narrowly spreads out in the vertical direction to tiny scratches on the polished surface due to abrasives. The deeper the scratch the more the dispersion, which means the rougher surface. The standard deviation of the pattern is nearly in proportion to the surface roughness. Measurement errors by this method are shown to be below 10 percent compared with those obtained by a common contact method. The inclination of measuring unit from the normal axis causes the measurement errors up to 10 percent for an angle of 4 degree. Therefore the proposed method can be used as an on-the-machine quick roughness estimator within 10 percent measurement error.
Multiple Vibration Control of a Trim Panel to Reduce Structure-borne Noise
Kim, In-Soo ; Kim, Yeung-Shik ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 153~163
A Camera Calibration Algorithm for an Ill-Conditioned Case
Lee, Jung-Hwa ; Lee, Moon-Kyu ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 164~175
If the camera plane is nearly parallel to the calibration board on which objects are defined, most of existing calibration approaches such as Tsai's radial-alignment-constraint method cannot be applied. Recently, for such an ill-conditioned case, Zhuang & Wu suggested the linear two-stage calibration algorithm assuming that the exact values of focal length and scale factor are known a priori. In this paper, we developed an iterative two-stage algorithm starts with initial guess fo the two parameters to determine the value of the others using Zhuang & Wu's method. In the second stage, the two parameters are locally optimized. This process is repeated until any improvement cannot be expected any more. The performance comparison between Zhuang & Wu's method and our algorithm shows the superiority of ours. Also included are the computational results for the effects of the distribution and the number of calibration points on the calibration performance.
Autonomous Robot Kinematic Calibration using a Laser-Vision Sensor
Jeong, Jeong-Woo ; Kang, Hee-Jun ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 176~182
This paper presents a new autonomous kinematic calibration technique by using a laser-vision sensor called "Perceptron TriCam Contour". Because the sensor measures by capturing the image of a projected laser line on the surface of the object, we set up a long, straight line of a very fine string inside the robot workspace, and then allow the sensor mounted on a robot to measure the point intersection of the line of string and the projected laser line. The point data collected by changing robot configuration and sensor measuring are constrained to on a single straght line such that the closed-loop calibration method can be applied. The obtained calibration method is simple and accurate and also suitable for on-site calibration in an industrial environment. The method is implemented using Hyundai VORG-35 for its effectiveness.
A Study on Improvement of Torsional Vibration Characteristics of a Driveline Using a Module-Type-Vibration Analysis System
Kim, Ki-Sei ; Hwang, Won-Gul ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 183~193
In the previous study, a module-type vibration analysis system using modular approach is developed for the purpose of analyzing the torsional vibration of vehicle driveline. In the present paper, the system is utilized to investigate the torsional vibration of the driveline of a middle duty truck. The driveline with driving condition is modeled and the torsional vibration response is simulated. The resonance 45Hz is found at engine speed 900rpm and the resultant vibration is very high. It shows favorable agreements with reference data. The effects of parameter change on torsional vibration are also investigated, so it is clarified that clutch characteristics, axle shaft stiffness are very influential on reduction of vibratio. So the countermeasure is proposed for the clutch characteristics. The reduction of torsonal vibration by 8rad/sec is obtained.
A Study of A Nonlinear Viscoelastic Model for Elastomeric Bushing in Torsional Mode
Lee, Seong-Beom ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 194~200
An elastomeric bushing is a device used in automotive suspension systems to cushion the force transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid metal shaft at its inner surface and a metal sleeve at its outer surface. For axial motion case, the relation between the force applied to the shaft and their relative displacement was considered. In this paper, the relation between the moment applied to the shaft and their relative deformation(angle of rotation) is considered for the torsional motion case. Numerical solutions of the boundary value problem represent the exact bushing response for use in the method for determining the moment relaxation function of the bushing. Solutions also allow for comparison between the exact moment-deformation behavior and that predicted the proposed model. It is shown that the predictions of the proposed moment-deformation relation are in very good agreement with the exact results.
Modeling and Measurement of Geometric Errors for Machining Center using On-Machine Measurement System
Lee, Jae-Jong ; Yang, Min-Yang ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 201~210
One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric and thermal errors of the machine tools. Therefore, a key requirement for improving te machining accuracy and product quality is to reduce the geometric and thermal errors of machine tools. This study models geometric error for error analysis and develops on-machine measurement system by which the volumetric erors are measured. The geometric error is modeled using form shaping function(FSF) which is defined as the mathematical relationship between form shaping motion of machine tool and machined surface. The constant terms included in the error model are found from the measurement results of on-machine measurement system. The developed on-machine measurement system consists of the spherical ball artifact (SBA), the touch probe unit with a star type stylus, the thermal data logger and the personal computer. Experiments, performed with the developed measurement system, show that the system provides a high measuring accuracy, with repeatability of
in X, Y and Z directions.
Application of Neural Networks to Sensor Failure Detection, Identification, and Accommodation
An, Young-Hwan ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 211~217
Modeling and Dynamic Analysis of Electro-mechanical System in Machine Tools(2
Report) - Modeling and Dynamic Analysis of Feed Drive System -
Park, Yong-Hwan ; Shin, Heung-Chul ; Moon, Hee-Sung ; Choe, Song-Yul ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 218~224
In the feed drive systems of machine tools that consist of many mechanical components such as motor, coupling, ballscrew, nut or table, a torsional vibration is often generated because of its elastic elements in torque transmission. Generally, the accuracy of motion control system is strongly influenced by the dynamic behavior of coupled transmission components. Especially, a torsional vibration caused by the elasticity of mechanical elements might deteriorate the quick movement of system and lead to shorten the life time of the mechanical transmission elements. So, it is necessary to analyze the electromechanical system mathematically to optimize the dynamic characteristics of the feed system. In this paper, the mathematical model of a feed drive system was developed and its mechanical characteristics were analyzed on the basis of the proposed model. The design concepts of speed control loop to stabilize a feed drive system were also proposed.
A Numeric Modelling Technique for the Shape Development of Fatigue Crack
Han, Moon-Sik ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 225~233
This paper describes a versatile finite element technique which has been used to investigate of wide range of structural defects of practical importance. The procedure automatically remeshes the three-dimensional finite element model during the stages of crack growth. Problems analyzed to date include the surface cracks in leak-before-break situations, the development of quarter-elliptical corner defects, planar semi-elliptical surface defects and the fatigue growth of defects.
Plane Surface Generation with a Flat End Mill
Ryu, Si-Hyeong ; Kim, Min-Tae ; Choe, Deok-Gi ; Ju, Jong-Nam ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 2, 1999, Pages 234~243
Using the geometric and the vector methods, three dimensional surface texture and roughness models in flat end milling are developed. In these models, rear cutting effect on surface generation is considered along with tool run-out and tool setting error including tool tilting and eccentricity between tool center and spindle rotational center. Rear cutting is the secondary cutting of the already machined surface by the trailing cutting edge. The effects of tool geometry and tool deflection on surface roughness are also considered. For representing the surface texture more practically, three dimentional surface topography parameters such as RMS deviaiton, skewness and kurtosis are introduced and used in expressing the surface texture characteristics. Under various cutting conditions, it is confirmed that the developed models predict the real surface profile precisely. These models could contribute to the cutter design and cutting condition selection for the reduction of machining and manual finishing time.