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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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Measurement of Motion Accuracy by Two-dimensional Probe on NC Machine Tools -2nd Report, Measurement of the Linear Motion Accuracy-
E.C. Jeon ; S. OYAMADA ; J. KAKUTA ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 15~21
This paper presented a linear motion accuracy by using two-dimensional probe with the master block and the square for NC machine tools. This measuring system could be measured motion error due to numerical control system. The results of measurement and simulation for motion error were similar, and so, this system had enough accuracy to measure a linear motion accuracy for NC machine tools. The experimental results are as follows. 1. This measuring system could be measured motion error due to mumerical control system. 2. The results of measurement and simulation for motion error were similar. 3. This measuring system had enough accuracy to measure a linear motion accuracy for NC machine tools.
Turning and Metalic Characterization for CAM Shaft Materials of Diessel Engine
W.S. Chae ; Kim, K.W. ; Kim, D.H. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 22~28
In this paper, We have studied internal quality incluiding chemical compositions, microscopic structure and nonmetalic inclusion of test material. We have analyzed dynamic characteristics of cutting resistence and compared chip treatment of the test material. In analyzing internal quality, all of the test material have typical ferrite+pearlite structure. But, nonmetallic inclusion has oxide and sulfide inclusion has oxide and sulfide inclusion in medium carbon steel, mainly sulfide inclusion is existed in S-free cutting steel. In Ca+S-free cutting steel, calcium aluminate and sulfide complex inclusion, had low-melting point, as deformation of sulfide and oxide inclusion is existed. Machining characteristics, cutting resistence is maximum in medium carbon steel. Chip treatement are excellent in S-free cutting steel, similar to the Ca+S free cutting steel and medium carbon steel.
Empirical Closed Loop Modeling of a Suspension System Using Neural Network
Kim, I.Y. ; Chong, K.T. ; Hong, D.P. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 29~38
A closed-loop system modeling of an active/semiactive suspension system has been accomplished through an artificial neural network. A 7DOF full model as a system's equation of motion has been derived and an output feedback linear quadratic regulator has been designed for control purpose. A training set of a sample data has been obtained through a computer simulation. A 7DOF full model with LQR controller simulated under several road conditions such as sinusoidal bumps and rectangular bumps. A general multilayer perceptron neural network is used for dynamic modeling and target outputs are fedback to the a layer. A backpropagation method is used as a training algorithm. Model validation of new dataset have been shown through computer simulations.
An Automated Process Planning System for Blanking or Piercing of Irregular-Shaped Sheet Metal Products (ll)
J.C. Choi ; B.M. Kim ; J.H. Kim ; H.K. Kim ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 39~48
This paper describes the process planning system of a computer-aided design of blanking and piercing for irregularly shaped sheet metal products. An approach to the system is based on knowledge-based rules. The process planning system is designed by considering several factors, such as the complexity of blank geometry, production feasibility of products, and punch profile complexity. Therefore this system which was implemented production feasibility check and strip layout module can carry out a process planning considering a production feasibility area of both internal and external features, a dimension of blanked hole, a coner and a fillet radius for irregualrly shaped sheet metal products and generate the strip layout in graphic froms. Knowledges for process planning are extracted from plasticity theories, handbooks, relevant references and empirical know- hows of experts in blanking companies. This provides powerful capabilities for process planning system of irregularly shaped sheet metal products.
An Optimal Tool Selection Method for Pocket Machining
Y.M. Kyoung ; K.K. Cho ; C.S. Jun ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 49~58
In process planning for pocket machining, the selection of tool size, tool path, overlap distance, and the calculation of machining time are very important factors to obtain the optimal process planning result. Among those factors, the tool size is the most important one because the others depend on tool size. And also, it is not easy to determine the optimal tool size even though the shape of pocket is simple. Therefore, the optimal selection of tool size is the most essential task in process planning for machining a pocket. This paper presents a method for selecting optimal toos in pocket machining. The branch and bound method is applied to select the optimal tools which minimize the machining time by using the range of feasible tools and the breadth-first search.
A Motion Capture and Mimic System for Motion Controls
J.S. Yoon ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 59~66
A general procedure for a motion capture and mimic system has been delineated. Utilizing sensors operated in the magnetic fields, complicated and optimized movements are easily digitized to analyze and repreduce. The system consists of a motion capture module, a motion visualization module, a motion plan module, a motion mimic module, and a GUI module. Design concepts of the system are modular, open, and user friendly to ensure the overall system performance. Custom-built and/or off-the-shelf modules are ease- ly integrated into the system. With modifications, this procedure can be applied for complicated motion controls. This procedure is implemented on tracking a head and balancing a pole. A neural controller based on this control scheme dtilizing human motions can easily evolve from a small amount of learning data.
Basic Study on in-Process Monitoring of B.U.E. Using Force Sensor
J.S. Won ; M.S. Oh ; Y.G. Jung ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 67~72
Recently, in order to achieve high flexibility of manufacture, monitoring and control strategies of a new type have been developed. Since the generation of built-up edge on the cutting tool damages the surface finish of the workpiece, the monitoring system of built-up edge is an important process monitoring. In this study, the analyzing methods of cutting force signal to detect the built-up edge during cutting process are described. The cutting force signals are analyzed using the mean, standard deviation and mean to standard deviation of this cutting signals. We can obtain the guide to detect the built-up edge during turning process.
Robust Hybrid Control for Uncertain Robot Manipulators
M.C. Han ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 73~81
An new class of robust position/force hybrid control law is proposed for uncertain robot manipulators. The uncertainty is nonlinear and (plssibly fast) time-varying. Therefore, the uncertain factors such as imper- fect modeling, friction, payload change, and external disturbance are all addressed. Based on the possible bound of the uncertainty, the controller is constructed and the stability study based on Lyapunov function is presented. To show that the proposed control laws are indeed applicable, the theoretical result is applied to a SCARA-type robot manipulator and simulation result is presented.
Effect of Crack Closure on the Fatigue Crack Growth Behavior of Forged AI7050-T7452
Lee, W.S. ; Park, J.Y. ; Lee, H.W. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 82~90
When a structure is made by the process of forging, it has the different mechanical properties from those it has before the process. This study is based on the crack closure phenomenon of the crack growth behavior of forged AI7050-T7452. The specimens were prepared in three kinds of forging ratio in order to find out the effects of crack closure on the forged material and compare the crack growth behavior with not-forged aluminum. COD method and strain gage method were used in measuring the crack closure stress and the results from those methods were compared each other. FEM analysis was applied to verify the effective stress intensity factor range by the superposition of the crack closure load to the crack tip. In the result of this study, the crack closure stress decreased with increasing the forging ratio due to the finer grain size and the brittle manner.
Life Prediction by Lethargy Coefficient under Dynamic Load
Kwon, S.J. ; Song, J.H. ; Kang, H.Y. ; Yang, S.M. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 91~98
Because of a complicated behavior of fatigue in mechanical structures, the analysis of fatigue is in need of much researches on life prediction. A method is developed for the dynamic tensile strength analysis by simple tensile test, which is for the failure life prediction by lethargy coefficient of various materials. Then it is programed to analyze the failure life prediction of mechanical system by virtue of fracture. Thus the dynamic tensile strength analysis is performed to evaluate life parameters as a numerical example, using the developed method.
A Study on the Machining Operations Planning for the Flexible Machining Process
Y.S. Chang ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 99~107
An algorithm is developed to find optimal machining parameters for multiple machining environments. The cutting rate-tool life (R-T) characteristic curve presents the general loci of optima and is useful for the flexible machining operations planning. The R-T characteristic curve for the machining economics prob- lems with linear-logarithmic tool lofe model may be determined by applying sensitivity analysis to log-dual problems. Three cases of the change of machining environments are considered. An end milling example is constructed to illustrate the algorithm.
Interference-Free Tool Approach Directions in Multi-Axis NC Machining of Sculptured Surfaces
J.G. Kang ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 108~115
In this paper, an algorithm of computing interference-free tool approach directions(visibility cone) with consideration of tool volume at an arbitrary point of a sculptured surface is developed. The surface is first approximated into a polyhedron with smaller subpatches and the tool approach directions are evenly sampled so as to test accessibility. Then the visibility cone is computed by testing if each approach direction is interfered by other surface subpatches. The results are represented as the binary spherical map which transform geometric information on sphere into aogebraic one. The developed algorithm is implemented and tested by several sculptured surfaces, convincing it can be easily used as a tool for not only interference- free tool approach directions but also determining process planning of multi-axis NC machining of sculp- tured surfaces
Impact Damage of CFRP Laminated Composites Subjected to Impact Loading
M.S. KiM ; Park, S.B. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 116~125
An investigation was performed to study the impact damage in CFRP laminated composites subjected to impact loading. A finite element model has been developed for predicting the impact damage in laminated composite plates resulting from the ballistic impact. The finite element model was based on the higher-order shear deformation theory and was used to predict the initial intraply matrix cracking and the shape and size of interface delamination in laminated composites. Numerical simulation was performed and then the initiation of the matrix cracking and the shape and size of impacted induced delamination were predicted, and te results were compared with those of impact experiments with the same dimension and stacking sequences. A linear relationship holds between impact velocity and length and width of delamination. As impact velocity is increased, the increase of delamination length is highger than the increase of delamination width.,
Study of Intelligent Manufacturing System Development for Factory Automation
Park, K.H. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 126~136
This paper describes a task level cell programming environment that deals with difficulties in programming Flexible Manufacturing Cells (FMCs), and consists of the cell programming editor and the automatic generation module. In the cell programming editor, cell programs can be developed with task- oriented cell specifications that reduces the amount of details to be considered by cell programmers. The automatic generation module transforms task specifications into executable programs used by cell constituents. The development tool in designing the environment is an object-oriented approach which provides a simple to use and intuitive user interface, and allows for an easy development of object models associated with the environment. Test results are illustrated in order to demonstrate the applicability of the developed envifonment.
Effects of Suspension Compliance and Chassis Flexibility in Handling Performance
D.K. Kang ; W.S. Yoo ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 137~143
In this study, handling simulation of a passenger car is carried out to see the effects of suspension compliance, roll stabilizef bar and chassis flexibility. The front suspension of the car is a MacPherson strut type and the rear suspension is a multi-link type. The following five DADS models are constructed and compared to verify the effects of suspension compliance and chassis flexibility during lane change. (1) Vdhicle model without hard point compliance and stabilizer, (2) Vehicle model with hard point compoiance, (3) Vehicle model with hard point compliance and stabilizer, (4) Vehicle model with hard point compoiance, stabilizer, and one vibration mode of the chaxxis. (5) Vehicle model with hard point compliance, stabilizer, and three vibration modes of the chassis. The result shows that hard point compliance and stabilizer are significant in roll angle, and the flexibility of the chassis affects the yaw angle and yaw rate.
Inverse kinematics of a Reclaimer: Redundancy and a Closed- Form Solution by Exploiting Geometric Constraints
Hong, K.S. ; Kim, Y.M. ; Shin, K.T. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 144~153
The inverse kinematics problem of a reclaimer which excavates and transports raw materials in a raw yard is investigated. Because of the geometric feature of the equipment in which scooping buckets are attached around the rotating disk, kinematic redundancy occurs in determining joint variable. Link coordinates are introduced following the Denavit-Hartenbery representation. For a given excavation point the forward kinematics yields 3 equations, however the number of involved joint variables in the equations is four. It is shown that the rotating disk at the end of the boom provides an extra passive degree of freedom. Two approaches are investigated in obtaining inverse kinematics solutions. The first method pre-assigns the height of excavation point which can be determined through path planning. A closed form solution is obtained for the first approach. The second method exploits the orthogonality between the normal vector at the excavation point and the z axis of the end-effector coordinate system. The geometry near the reclaiming point has been approximated as a plane, and the plane equation has been obtained by the least square method considering 8 adjacent points near the point. A closed form solution is not found for the second approach, however a linear approximate solution is provided.
Motion Control Design of Constrained Mechanical Systems
Journal of the Korean Society for Precision Engineering, volume 14, issue 7, 1997, Pages 154~162