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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 12, Issue 12 - Dec 1995
Volume 12, Issue 11 - Nov 1995
Volume 12, Issue 10 - Oct 1995
Volume 12, Issue 9 - Sep 1995
Volume 12, Issue 8 - Aug 1995
Volume 12, Issue 7 - Jul 1995
Volume 12, Issue 6 - Jun 1995
Volume 12, Issue 5 - May 1995
Volume 12, Issue 4 - Apr 1995
Volume 12, Issue 3 - Mar 1995
Volume 12, Issue 2 - Feb 1995
Volume 12, Issue 1 - Jan 1995
Selecting the target year
Machine Tool Technology;The Present And The Future(3)
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 5~12
On the Development of Spot and ARC Welding Dual-Purpose Robot System
G.S. Ryu ; Lee, Y.J. ; Lee, Y.B. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 13~19
A dual purpose robot automation system is developed for both arc welding and spot welding by one robot within a cell. The need for automation of both arc welding and spot welding processes is urgent while the production volume is not so big as to accommodate separate stations for the two processes. Also, space is too narrow for separate stations to be settled down in the factory. A spot welding robot is chosen and the functions for arc welding are implemented in-house at cost of advanced functions. For the spot welding, a single pole type gun is used and the robot has to push down the plate to be wolded, which causes the robot positioning error. Therefore, position error compensation algorithm is developed. The basic functions for the arc welding processes are implemented using the digital I/O board of robot controller, PLC, and A/D conversion PCB. The weaving pattern is taught in meticulously by manual teach. A fixture unit is also developed for dual purpose. The main aspects of the system is presented in this paper especially in the design and implementation procedure. The signal diagrams and sequence logic diagrams are also included. The outcome of the dual purpose welding cell is the increased productivity and good production stability which is indispensable for production volume prediction. Also, it leads to reduction of manufacturing lead time.
The Effects of Si Content on the Cutting Characteristics in the Turing Process of A1-Si Alloy, Using a Polycrystalline Diamond Tool
Lee, K.H. ; Y.S. Yun ; Lee, S.J. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 20~26
With the recent development of light and high efficient automobiles and aircraft, demand of the A1-Si alloy is rapidly increasing. However, there is an inclination that as the content of silicon increases it becomes more difficult to machine. Accordingly, the present study intends to analyse and study the cutting resistance and surface roughness of A1-Si alloy with Si contents of 8%, 12%, 17%, and 20%. The A1-Si alloy specimens were turned by a poly- crystalline diamond tool under selected cutting conditions, and results are here described and discussed.
An On-line Algorithm for Machine Layout Problem
G.N. Wang ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 27~36
This paper covers algorithms to determine a machine assignment strategy to locations on a single straight track by minimizing the total backtrack distance. Three different algorithms ar presented: an efficient heuristic procedure, the branch-and-bound algorithm, and the nerual network approach. Simulation results show that the proposed algorithms have potential power to design an on-line optimizer.
A development of the Grinding Expert System by Fuzzy Decision Making
S.R. Shin ; J.P. Kang ; J.B. Song ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 37~44
Grinding is used for machining high precision parts with high additional value. However, the grinding operation needs high skill and long experience of an operator because of a lack of the scientific knowledge and engineering principles. Also, the wheel and grinding conditions affect grinding results. For these reasons, it is difficult to construct computer integrated manufacturing system(CIMA). Therefore, it is necessary for Expert System to be informed of qualitative knowledge of grinding expert's skills and experiences. In this research, the Grinding Expert System is constructed by Fuzzy Decision Making Algorithm. Using this system, unskilled workers will be able to use the knowledge and experience of an expert.
Control of Stick-Slip Friction with a CMAC
Park, J.H. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 45~51
This paper proposes a CMAC-based controller for servo systems with stick-slip friction. Performance of the controller was evaluated from computer simulations and compared with that of a conventional PID controller. Firction model used in the simulations is based upon the one proposed by Tustin. It was shown that the CMAC-based controller settles more quickly, and overshoots less than the PID. It was also shown that the CMAC is less sensitive to the changes of the plant parameters.
A Study of Motion for Four-Axis Stabilized Platform Including Effects of Gimbal Bearing Friction
Y.J. Shin ; J.K. Lee ; S. Choi ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 52~63
This paper presents a detailed derivation of the equations of motion for the stable member of a four-axis platform. Gimbal bearing friction is considered for motion analysis. First, dynamic characteristics of platform, gimbal and gyro with Coulomb friction are studied due to vehicle's angular motion. Second, Vehicle's motion is assumed the sinusoidal function and dynamic characteristics of platform, gimbal and gyro are studied. Conclusively, considering effects of Coulomb friction, they could not follow the vehicle's angular motion and have constant errors. In case of sinusoidal motion, relative angles for each gimbal are amplified, but they are sinusoidal function with almost the same phases.
A process analysis system using Fuzzy reasoning networks for quality control of cutting
J.H. Hong ; O. Sigeo ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 64~71
The objective of this paper is to realize an analysis system that is capable of controlling the quality of an entire cutting process by including a 3 coordinate measuring machine in the process line. Fuzzy reasoning networks based on fuzzy associative memories has been intro- duced in the measuring process, the control limits for the control process have been obtained, and the efficiency and reliability of the system have been determined by examining the simu- lated reasoning control values.
Development for Automatic Thickness Measurment System by Digital Image Processing
Kim, Y.I. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 72~79
The purpose of this paper is to develop an automatic measuring system based on the digital image processing which can be applied to the in-process measurment of the characteristics of the thin thickness. The derivative operators is used for edge detection in gray level image. This concept can be easily illustrated with the aid of object shows an image of a simple light object on a dark background, the gray level profile along a horizontal scan line of the image, and the first and second derivatives of the profile. The first derivative of an edge modeled in this manner is 0 in all regions of constant gray level, and assumes a constant value during a gray level transition. The experimental results indicate that the developed automatic inspection system can be applied in real situation.
Elimination of Branch Problem in Driving Crank Center point Plane for 3 Position Synthesis of 4 bar Mechanism
J.H. Borm ; Kim, H.R. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 80~86
A method of eliminating the branch problem in driving crank center point plane for 3 position synthesis of 4 bar mechanism is introduced. By studying various transformation characteristics from the circle point plane into the center poi t plane, the curves in the center point plane transformed from the filemon line in circle point plane are analytically obtained, which will seperate the whole center point plane into many sub-areas for the selec- tion of the center point of the driving crank. And a simple method to identify which of the sub-areas will cause the branch problem is also presented. The method will allow the selection of the center point of driving crank without the branch problem.
Pridiction of Case Depth in Laser Beam Hardening
Kim, J.D. ; C.D. Cho ; Y.M. Cho ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 87~95
In order to predict the case depth and case width in laser transformation hardening, a finite element method was used to analyze the temperature distribution on the material. Laser hardening of the specimens of SM45C and STE11steels was experimented by using the continuous wave CO
laser with the various travel speeds and the defocused Gaussian beam mode. Phosphate coating was adopted on the surface of SM45C to increase the absorption of 10.6 .mu. m laser energy. Experimental data show good agreement with the theoretical predictions. The maximum possible case depth can be predicted for the given laser hardening conditions, such as laser power, and travel speed.
A Learning Control Algorithm for Noncircular Cutting with Lathe
Lee, J.G. ; C.J. Oh ; Kim, O.H. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 96~104
A study for a lathe to machine workpiece with noncircular cross-section is presented. The noncircular cutting is accomplished by controlling radial tool position synchronized with revolution angle of the spindle according to the desired cross-sectional shape. A learning control algorithm is suggested for the tool positioning. The learning law of the algorithm is based on pole-zero cancellation, which guarantees the control stability. The control performances are analyzed and simulated on a numerical computer that the effectiveness of the control algorithm is convinced. The algorithm is tested on a conventional NC-lathe which shows some successful results.
Dynamic Equations of Robots and Sensitivity Analysis
S.J. Song ; Lee, J.M. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 105~111
The inverse dynamic equations for 5 link robot including a closed chain have been derived. The closed chain is virtually cut open, and the kinematics and dynamics of the virtual open chain robot are analyzed. The constraints are applied to the virtually cut joints by the Jacobian matrix which represents the configuration of the closed chain. The topology of tree structrued open chain robot is described by a FATHER array. The FATHER array of a link indicates the link tha tis connected in the direction of base link. Based on the inverse dynamic equations, the torque sensitivity models of the 5 link robot have been developed. The sensitivity models characterize the sensitivity of the driving torque with respect to the link parameters. All the procedures are illustrated through the 2 link robot.
A Study on the Early Fracture Characteristics of Ceramic Tool for Carbon Tool Steel
Kim, K.L. ; B.H. Ryu ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 112~119
Early fracture and cutting force of ceramic tool for hardened STC3 steel was investigated in this study. It was found that early fracture of ceramic tool was mostly occurred before normal wear was progressed beyond a critical cutting speed and normal wear was performed under the critical cutting speed. The relationships among critical cutting speed, which was a cause of early fracture, suggested cutting cross section, that is, maximum thickness of cut and width of cut, and cutting force were examined. The following conclusions were obtained: (1)Critical cutting speed showed a high value in the case of small maximum thickness of cut and large nose radius, but was not influenced by width of cut, (2)Principal, feed and radial force, respectively, showed the proportional value to constant cutting area, width of cut and maximum thickness of cut orderly, (3)Occurrence of early fracture was dependent upon radial force.
System Identification of Nonlinear System using Local Time Delayed Recurrent Neural Network
K.T. Chong ; D.P. Hong ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 120~127
A nonlinear empirical state-space model of the Artificial Neural Network(ANN) has been developed. The nonlinear model structure incorporates characteristic, so as to enable identification of the transient response, as well as the steady-state response of a dynamic system. A hybrid feedfoward/feedback neural network, namely a Local Time Delayed Recurrent Multi-layer Perception(RMLP), is the model structure developed in this paper. RMLP is used to identify nonlinear dynamic system in an input/output sense. The feedfoward protion of the network architecture provides with the well-known curve fitting factor, while local recurrent and cross-talk connections provides the dynamics of the system. A dynamic learning algorithm is used to train the proposed network in a supervised manner. The derived dynamic learning algorithm exhibit a computationally desirable characteristic; both network sweep involved in the algorithm are performed forward, enhancing its parallel implementation. RMLP state-space and its associate learning algorithm is demonstrated through a simple examples. The simulation results are very encouraging.
Time-Optimal Multistage Controllers for Nonlinear Continuous Processes
J.S. Yoon ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 128~136
The problem addressed in this paper is that of the on-line computational burden of time-optimal control laws for quick, strongly nonlinear systems like revolute robots. It will be demonstrated that a large amount of off-line computation can be substituted for most of the on-line burden in cases of time optimization with constrained inputs if differential point-to- point specifications can be relaxed to cell-to-cell transitions. These cells result from a coarse discretization of likely swaths of state space into a set of nonuniform, contiguous volumes of relatively simple shapes. The cell boundaries approximate stream surfaces of the phase fluid and surfaces of equal transit times. Once the cells have been designed, the bang- bang schedules for the inputs are determined for all likely starting cells and terminating cells. The scheduling process is completed by treating all cells into which the trajectories might unex- pectedly stray as additional starting cells. Then an efficient-to-compute control law can be based on the resulting table of optimal strategies.
A study on the tire structure vibration for road noise reduction and chassis design
Y.S. Song ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 137~144
The purpose of this study is to obtain a foundation data for chassis design and road noise reduction of automobiles. Using the combination of the automobile, radial tires and instrumentation equipment, experimental investigation was carried out to examine the characteris- tics of the structural vibration of tire as the key to obtaining the effective parameters for reducing road noise. From the results of this studies it has been confirmed that the specific ranges of natural frequency of tire exciting the suspension and chassis system. And the tire, axle and chassis natural frequency of automobile govern the road noise. Results show that material properties of tire and experimental condition are major parameter for shifting of tire natural frequency. These results would be utilized as basic materials for the design of chassis design with papametric study, which enables a designer of an automobile to foresee the influence of the various design factors or operating conditions.
Analytic Linearization of Symbolic Nonlinear Equations
S.J. Song ; H.K. Moon ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 6, 1995, Pages 145~151
The first-order Taylor series expansion can be evaluated analytically from the formulated symbolic nonlinear dynamic equations. A closed-form linear dynamic euation is derived about a nominal trajectory. The state space representation of the linearized dynamics can be derived easily from the closed-form linear dynamic equations. But manual symbolic expansion of dynamic equations and linearization is tedious, time-consuming and error-prone. So it is desirable to manipulate the procedures using a computer. In this paper, the analytic linearization is performed using the symbolic language MATHEMATICA. Two examples are given to illustrate the approach anbd to compare nonlinear model with linear model.