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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 14, Issue 12 - Dec 1997
Volume 14, Issue 11 - Nov 1997
Volume 14, Issue 10 - Oct 1997
Volume 14, Issue 9 - Sep 1997
Volume 14, Issue 8 - Aug 1997
Volume 14, Issue 7 - Jul 1997
Volume 14, Issue 6 - Jun 1997
Volume 14, Issue 5 - May 1997
Volume 14, Issue 4 - Apr 1997
Volume 14, Issue 3 - Mar 1997
Volume 14, Issue 2 - Feb 1997
Volume 14, Issue 1 - Jan 1997
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Error Aalysis of Mechanical Parts and Dynamic Balancing in A Dynamically Tuned Gyroscope
J.O. Young ; C.G. Ahn ; Lee, J.M. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 13~22
Strapdown inertial navigation system(SDINS) is a navigational instruments necessary to guide and con- trol a free vehicle. In this study, an error analysis of mechanical parts is carried out for manufacturing a dynamically tuned gyroscope. The errors usually come from the tolerance in machining and assembly. In the error analysis, a criterion to be considered during designing and manufacturing is proposed by quanti- tatively analyzing the effect of DTG performance by tolerances. The theory of dynamic balancing is deduced and unbalance is reduced through experiment.
Analysis Of The Thermal Behavior and Jacket Cooling Characteristics of Motor Integrated Spindle for High Speed Machine Tool
Park, D.B. ; Kang, J.P. ; Song, J.B. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 33~40
Recently, there are an increasing needs for high speed rotating spindle which is an important mechanical ele- ment for a high efficiency machine tool in order to shorten machining time and cut production costs. The heat gen- eration is the most important problem in the motor integrated spindle. In this study, the effects of temperature distribution and thermal behavior according to the oil-air lubrication and cooling conditions are investigate theo- retically and experimentally on the motor-integrated spindle under unloading condition. The experimental spin- dle system is composed with the angular contact steel ball bearings, oil-air lubrication, air or oil jacket cooling system. To analyze the thermal behavior and cooling characteristics for the motor integrated spindle, the analysis using the finite element method is carried out. The analytical results are compared with the experimental results.
Fault Detection and Isolation of System Using Multiple Pi Observers
Kim, H.S. ; Kim, S.B. ; Shigeyasu Kawaji ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 41~47
Fault diagnosis problem is currently a subject of extensive research in the control field. Although there are several works on the fault detection and isolation observers and the residual generators, those are con- cerned with only the detection of actuator failures or sensor failures. So, the perfect detection and isolation for the actuator and sensor failures is strongly required in the field of the practical applications. In this paper, a strategy of fault diagnosis using multiple proportional integral (PI) observers including the magnitude of actuator failures is provided. It is shown that actuator failures are detected and isolated perfectly by monitoring the integrated error between actual output and estimated output by a PI observer. Also in presence of complex actuator and sensor failures, these failures are detected and isolated by multiple PI observers.
A Study on Development of Vibration Analysis and CAD System for Vehicle Driveline Using Modular Approach
W.G. Hwang ; Kim, K.S. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 48~57
A computer aided analysis and design system is developed for analyzing the driveline torsional vibration of a vehicle. Torsional vibration characteristics of driveline component are investigated and 10 types of module are developed. They can be connected together to represent any driveline configuration. During assembly process simulation program is generated. It is implemented using C++language. A driveline tor- sional vibration system at full load driving condition and idle rattle system are modeled and simulated with this system. Their responses for engine torque excitation are evaluated on time and frequency domain, and the results are compared with test results favorably. This system makes it simpler and easier for design and analysis engineer to model and analyse the driveline system.
A Study on the Wear Characteristics and Lifetime Of High Chromium Roll
Kim, M.K. ; Kim, S.K. ; E.C. Jeon ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 58~65
Work rolls used in cold rolling mills must have outstanding wear resistance and very little plastic defor- mation. Thus, these rolls require a higher surface hardness and harding to a greater depth. To meet these requirements, the rolls, in general, have basic chemical composition of 0.7 to 1.0% carbon and 1.0 to 5.0% Cr(chromium), plus a small amounts of special elements, and are subjected to intensive water quenching and tempering at low temperature to provide a surface hardness of over 90 shore. This test results are as follows. Deflection and fracture load of 5% Cr material are than those of 3% Cr material and show flat curve from surface to subsurface. It will be clear that 5% Cr work roll has a superior resisti- bility against wear and abrasion comparing with 3% Cr work roll. The improvement of wear and abrasion in 5% Cr work roll will be achieved by the large amount of wpheroidal carbide. In grindability and polish, 5% Cr work roll will be a little inferior comparing with 3% Cr work roll.
Optimal Design of Machine Tool Structure for Static Loading Using a Genetic Algorithm
Park, J.K. ; H.G. Seong ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 66~73
In many optimal methods for the structural design, the structural analysis is performed with the given design parameters. Then the design sensitivity is calculated based on its structural anaysis results. There-after, the design parameters are changed iteratively. But genetic algorithm is a optimal searching technique which is not depend on design sensitivity. This method uses for many design para- meter groups which are generated by a designer. The generated design parameter groups are become initial population, and then the fitness of the all design parameters are calculated. According to the fitness of each parameter, the design parameters are optimized through the calculation of reproduction process, degradation and interchange, and mutation. Those are the basic operation of the genetic algorithm. The changing process of population is called a generation. The basic calculation process of genetic algorithm is repeatly accepted to every generation. Then the fitness value of the element of a generation becomes maximum. Therefore, the design parameters converge to the optimal. In this study, the optimal design pro- cess of a machine tool structure for static loading is presented to determine the optimal base supporting points and structure thickness using a genetic algorithm.
A Study on the Parameters Influence upon Automotive Neutral Gear Rattle
Hong, D.P. ; Chung, T.J. ; Ahn, B.M. ; Jeon, B.H. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 74~83
The non-periodic angular accelerations of engine are the major cause of gear rattle. This gear rattle is based on the existence of a backlash between the drive gear of input shaft and the free gear of output shaft in the gearbox. Especially, the neutral gear rattle have a very bad effect on the ride quality. Test-rig was constructed in order to evaluate the parameter influence upon the neutral gear rattle. Also, each different 4 type torsional characteristic of clutch was manufactured. Experimental conditions are the use of each different 4 type torsional characteristic of clutch and oil temperature variation in gearbox. In case of the same stiffiness of pre-damper type clutch at idling, the clutch of large hysteresis showed dam- ping effects at the 2nd input gear and the 2nd output gear. Also, the main-damper type clutch was shown to large resonance phenomenon at the 2nd input gear. Accordingly, main-damper type clutch was unapp- roriate at idling.
A Study of the Automation of Factory through the Development of UniSet
Park, K.H. ; Kim, S.C. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 84~91
This paper reports the effort for developing this new Unified Manufacturing Instruction Set and its environment, called here UniSet, to deal with difficulties in set up and operation of Flexible Manufacturing Cells, UniSet has been developed as a non-exclusive unified manufacturing instruction set based on com- parisons of the prevailing machine tool and programming primitives. UniSet allows programmers to deal with only one instruction set, if they so desire, in a single coherent enviroment, rather than numerous machine programming languges. The software system is coded in an Object-Oriented Programming (OOP) language, Smalltalk, and derives its paradigm from the OO philosophy. Test results are also includ- ed to demonstrate the applicability of the approach employed.
Modeling of 2D Joints Using Contact
H.S. Han ; Park, T.W. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 92~101
In this paper, modeling methods for 2D joints are proposed. Earlier methods for modeling 2D joints that use geometric relationships may not consider irregularities or dynamic effects of joints. In any case, it is important to consider irregularities or dynamic effects. To consider those, methods that use dynamic contacts are proposed. With the method, 2D joints that have irregularities or dynamic effects amy be model- ed and analyzed. 2D joints that are developed are revolute, translational, gear and point-follower joint.
Upper Bound Analysis on the Forging of Gear-Like Components
Min, G.S. ; Park, J.U. ; Lee, H.C. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 102~112
This paper describes the method that can construct kinematically admissible velocity fields for forging of gear-like components which have tooth shape around the cylinder. The kinematically admissible velo- city fields for the various gear-like components, involute spur gear, trapezoidal spline, square spline, ser- ration and trochoidal gear, were constructed by pilling up the velocity components according to the shape of tooth and billet. The billets, of hollow and solid, were Al 2218 and 2024. To verify the method, the analyses and experiments were carried out and compared with each other. For analyses, the half pitches of com- ponents were divided into several deformation regions based on their tooth profile. A neutral surface was used to represent the inner flow of material during forging. Its location varied with the energy optimazation and its contour varied with the number of teeth. In experiment, the contour of material filling up the tooth zone is hyperbolic curve caused by the frictional drag on the interface of die-wall/workpiece but, in the analysis, it is an arc which retains the same contour during all forging operation.
A Study on the Precision Cutting Characteristics of Al-alloy by the Diamond Tool with the Straight Cutting Edge
Yu, K.H. ; Cheong, C.Y. ; Seo, N.S. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 113~119
This research intents to gain the sight for the qualitative characteristics of precision cutting by using the CNC lathe with a mono-crystal diamond(MCD) tool having a straight cutting edge. As an absolute value of tool setting angle becomes smaller, the surface roughness has improved. We knew that according to each of the machine tools and cutting edge radius, there exist a proper mininum feed and depth of engagement for improving the surface roughness. This results suggest that the proper values of feed and depth of engagement are about 11-15 .mu. m/rev, 10 .mu. m, respectively.
The Sensitivity Analysis and Optimization for the Development of the SMD Performance
I.H. Cha ; C.S. Han ; Kim, J.D. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 120~128
In this paper, A design strategy of the Surface Mounting Device for accurate and better performance is studied. Analytical modeling, sensitivity analysis, and optimization are being conducted. The ANSYS software and experimental method are used for the verification of the analytical equations with boundary conditions. Through the sensitivity analysis, the most dominant design parameter can be detected. The optimum design parameters for improving the given performances are selected by using the optimiza- tion algorithm. The design tool based on the design strategy for the analysis, modeling, and optimization will be useful for are-design and better improving of the SMD.
Determination of Initial Billet Shape to Improve Dimensional Accuracy in Backward Extruded Cups
Kim, H.C. ; Kim, T.H. ; Park, J.C. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 129~135
Experimental studies have been carried out to obtain uniform cups by one operation of backward extrusion. A lot of factors on dimensional accuracy of backward extruded cups are billet material, billet shape, punch shape, punch velocity, geometry of tool, tool material, and lubrication etc. In manufacturing cup-shaped parts by backward extrusion, it is very important to design the initial billet shape or the preform. The objective of this paper is to find that the shape of the initial billet is related to dimensional accuracy and also to manufacture the more accurate product simultaneously reducing the loss of material as forming the shape of the initial billet by means of upsetting.
Creation of Topological Information from STL Using Triangle Based Geometric Modeling
H.C. Chae ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 136~144
Usually triangular patches are used to transfer geometric shape in Rapid Prototyping CAM system. STL, a list of triangles, is de facto standard in RP industry. Because STL does not have topological infoma- tion, it can cause errornous results. So STL should be verified before using. After adding support structures to anchor the part to the platform and to prevent sagging or distortion, slicing and layer by layer manufactur- ing process are done. But triangular patch is surface model and cannot provide sufficient information on geometry in the above processes. So, geometric modeling is necessary in verifying STL, adding support structures and slicing. It is natural that triangle based modeling is the best when tringular patches are used as input. Considering support structures, solid and faces coexist in RP process. Therefore non-manifold modeler is required. In this study, triangle based non-manifold geometric modeling is proposed for RP sys- tem consistent with STL input.
Elastic-plastic Contact Stress Analysis of CRT Glass Bulb
D.J. Kang ; W.S. Shin ; C.S. Song ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 145~151
In this paper, we discuss the cathode ray tube(CRT) glass bulb stress and sagging recovery by the contact band pressure using finite element method. We analyzed the band pressure and stress using contact element method between band and bulb before and after banding process which was conducted to decrease the stress concentration using finite element method, and calculated sagging recovery. The analysis results were confirmed by experiments using strain gauge and sagging recovery test apparatus.
Convergence of Infinite Dimensional Adaptive Systems and Persistence of Excitation of Related Signals
K.S. Hong ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 152~159
The asymptotic convergence of a coupled dynamic system, which is motivated from infinite dimensional adaptive systems, is investigated. The convergence analysis is formulated in abstract Banch spaces and is shown to applicable to a broad class of infinite dimensional systems including adaptive identification and adaptive control. Particularly it is shown that if a uniquely existing solution is p-th power integrable, then the solution converges to zero asymptotically. The persistence of excitation(PE) of a signal which arises in an infinite dimensional adaptive system is investigated. The PE property is not completely known yet for infinite dimensional adaptive systems, however it should be investigated in relation to spatial variable, boundary conditions as well as time variable.
Self-Tuning Control of a Flexible Link Robot with Unknown Payload
K.B. Han ; Lee, S.B. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 160~168
self-tuning control scheme for the tip position of a flexible link robot handling unknown loads is presented here. The scheme essentially comprises a recursive least-squares identification algorithm and
self-tunning controller. The
control low is designed to be robust to uncertain parameters and the self-tunning action provides adaption to unknown parameters. Through numerical study, the performance comparison of the
self-tuning controller with a constant gain
controller as well as a LQG self-tuning controller clearly shows its superior ability in handling load changes in quiescent states.nt states.
Prediction of Specific Cutting Pressure in Face Milling Considering Tool Rake Angles
S.H. Ryu ; C.N. Chu ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 2, 1997, Pages 169~177
In this study, investigated are the effects of tool rake angles and the change of cutting conditions on the specific cutting pressure in face milling. The cutting force in face milling is predicted from the double cutting edge model in3-dimensional cutting. Conventional specific cutting pressure model is modified by considering the variation of tool rake angles. Effectiveness of the modified cutting force model is verified by the experiments using special face milling cutters with different cutter pockets and various rake angles. From the comparison of the presented model and the specific cutting pressure, it is shown that the axial force can be predicted by the tangential force, radial force and geometric conditions. Also, the rela- tionship between specific cutting pressure and cutting conditions including feedrate, cutting velocity and depth of cut is studied.