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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
Editor in Chief :
Volume & Issues
Volume 11, Issue 6 - Dec 1994
Volume 11, Issue 5 - Oct 1994
Volume 11, Issue 4 - Aug 1994
Volume 11, Issue 3 - Jun 1994
Volume 11, Issue 2 - Apr 1994
Volume 11, Issue 1 - Feb 1994
Selecting the target year
An Improvement of Positioning Accuracy for CNC Machine Tools
E.C.Jeon ; Y. Hirota ; S. Namgung ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 5~11
We have investigated the variation of dwell and warm-up time for effects of positioning accuracy of the CNC machine tools with an laser measuring system. Also, we strdied the effect of improvement of the positioning accuracy by variation of the temperature for hollow ball screw, which mostly used as drive mechanism of CNC machine tools. We dbtained the effectiveness of cooling effect of the new cooling system, compared with the conventional cooling system.
Effects of Heat-treatment on the Bending Fatigue Strength of SNC 815 Carburized Spur Gear
S.K. Lyu ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 12~19
This paper deals with the bending fatigue strength of SNC815 carburized spur gears. The test gears are heat-treated by two different treatments. One is the direct quenching after car-burization. The other is treated by reheating and quenching. The fatigue test at a constant stress amplitude is performed by using an electrohydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. The fatigue strength of direct quenched gears is higher than that of reheated quenched gears. The fatigue strength is estimated from the hardness and the residual stress by using the experimental formula proposed by Tobe and Inoue. The estimated strength is close to the test results, and the validty of the formular is confirmed.
An improved Robust and Adaptive Controller Design for a Robot Manipulator
Park, H.S. ; Kim, D.H. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 20~27
This paper presents a controller design to coordinate a robot manipulator under unknown system parameters and bounded disturbance inputs. To control the motion of the manipulator, an inverse dynamics control scheme is applied. Since parameters of the robot manipulators such as mass and inertia are not perfectly known, the difference between the actual and estimated parameters works as a disturbance force. To identify the unknown parameters, an improved adaptive control algorithm is directly derived from a chosen Lyapunov's function candidate based on the Lyapunov's Second Method. A robust control algorithm is devised to counteract the bounded disturbance inputs such as contact forces and disturbing forces coming from the difference between the actual and the estimated system parameters. Numerical examples are shown using three degree-of-freedom planar arm.
Automatic Tool Selection and Path Generation for NC Rough Cutting of Sculptured Surface
S.E. Hong ; Lee, K.W. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 28~41
An efficient algorithm is proposed to select the proper tools and generate their paths for NC rough cutting of dies and molds with sculptured surfaces. Even though a milling process consists of roughing, semi-finishing, and finishing, most material is removed by a rough cutting process. Therfore it can be said that the rough cutting process occupy an important portion of the NC milling process, and accordingly, an efficient rough cutting method contributes to an efficient milling process. In order work, the following basic assumption is accepted for the efficient machining. That is, to machine a region bounded by a profile, larger tools should be used in the far inside and the region adjacent to relatively simple portion of the boundary while smaller tools are used in the regions adjacent to the relatively complex protion. Thus the tools are selected based on the complexity of the boundary profile adjacent to the region to be machined. An index called cutting path ratio is proposed in this work as a measure of the relative complexity of the profile with respect to a tool diameter. Once the tools are selected, their tool paths are calculated starting from the largest to the smallest tool.
A Study on the Chip Control in Machining STS304 Using a Chip Breaker
Yeom, D.W. ; Yu, K.H. ; Seo, N.S. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 42~49
One of the parameters that influence the productivity of every industry, involved in metal cutting, is the chip from ; continuous or broken chip. Chip form varies according to machining conditions, material used, tool geometry and chip breaker geometry. Therefore, in this study we carried out the experiment on the chip control in machining STS304 using an attached obstruction type chip breaker. Namely, with the change of a chip breaker distance, chip breaker angle, cutting characteristics in machining STS304 which is well-known as a machining difficult material and produces a saw-toothed chip. The results of the experiment are as follows : 1. The chip breaker distance and angle under which the preferred chip is produced, show 1.5mm and 60 .deg. , while chip breaker angle in machining an ordinary steel was well-known 45 .deg. . 2. During the cutting process, the change of feed than the change of velocity was applied as cutting conditions, effects more clearly on the chip breaking. 3. Considering a whole surface roughness, it is not advisable to apply chip breaker mentioned above for precision cutting.
Design and Performance Evaluation of DC Generator Control System for Cortrolling Torque of Rotating Shaft
Kim, G.S. ; D.I. Kang ; B.D. Ahn ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 50~56
A DC generator control system was designed to control the torque of a rotating shaft precisely. The control system is composed of a strain gage type torque cell, a torque cell amplifier, a computer, a D/A converter, a error detector, a DC voltage amplifier and a resistor. The response test under unit step input and the dynamic stability test for the designed control system were carried out. It was confirmed that the settling time from the response test is about 4 s and the error from the dynamic stability test is less than 0.06% of rated output of torque cell. The designed control system may be used to control a DC generator which may be used to apply torque to a rotating shaft.
A study on Fuzzy-PID Control of a Straight Line Type Inverted Pendulum
Kim, J.M. ; Lee, S.G. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 57~64
This paper proposes a fuzzy tuning PID controller for straight line type inverted pendulum. The conventional PID controller which is used widely in industrial field has fatal drawback on determining control gains for practical system. The proposed controller tunes the gains automatically based on fuzzy urle derived from the experience of expert operator. The results of simulation and experiment show the efficiency of the proposed control method comparing with conventional PID control method in terms of rising time, overshoot, and overall errors.
Modal Analysis of Plate by Substructure Synthesis Method
J.H. Jung ; T.H. Jee ; Park, Y.P. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 65~74
Various substructure synthesis methods, such as component mode synthesis, building block analysis and reduced impedance method, are studied for the determination of vibration characteristics of plate problems. Comparisons are made for each methods in terms of accuracy and computational efficiency. Following conclusions are made from the results of computer simulations and experiments. i) The computation time of component mode synthesis is much shorter than that of whole structure analysis. The natural frequencies of lower modes obtained from component mode synthesis are almost same as those obtained from whole structure analysis, but in higher modes the differences between those two methods are increases. ii) The transfer function obtained from building block analysis is same as that obtained from the finite element method. iii) Same transfer functions can be obtained by the reduced impedance method. The computation time of reduced impedance mathod is shorter that that of general finite element method, but for the solutions in broad frequency band it requires long calculation time.
Chaos analysis for the periodic nonlinear system using harmonic balance method
Kim, Y.B. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 75~85
Experimental investigation on the wear mechanism of CBN cutting tools
O.C. Kwon ; Lee, J.C. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 86~97
An experimental investigation is reported on the wear mechanism of CBN cutting tools. The cutting experiments were conducted on a lathe equipped with a tool dynamometer for cutting force measurement. The investigation of wear mechanism was executed by observing the worn tools using tool microscope and scanning electron microscope. Results indicate that the flank wear occurs dominantly by abrasive wear mode and the crater wear by adhesive wear mode. The results also indicate that the width of flank wear is closely related with the passive component of cutting force.
Tire Tread Pitch Noise Control System by Random Arrangement of Circumference Direction Straight Type Groove
Kim, B.S. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 98~108
An assessment of a mathematical method of synthesing tire tread pitch noise spectra is studied. The method is based on the summation of phasors and the calculated spectra are conveniently generated as computer printout in the form of bar graph. The technique, its usefulness, its limitations and the implications of using such a model are discussed. This paper presents a basic study on optimum pitch arrangement for prediction and control of tire tread pitch noise in constraint condition relatied with tire properties, thus enabling optimum tread pitch arrangements to be determined at the design stage, by application of old tire tread pitch simulation.
Dynamic Mass-measurement control System of Acceleration and Displacement Sensing Type
Kim, B.S. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 109~116
Quickness and precision are the two most important requirements for an industrial scale used in production lines. In this paper, a new approach, "Dynamic-Mass measurement control System of Acceleration and Displacement(DMS-AD) sensing", is presented to improve some of drowbacks in conventional scales. The system, consisted of acceleration and displace- ment sensors, spring scale and microcomputer, is based on full utilization of dynamic mass measurement of acceleration and displacement via microcomputer-assisted real time monitoring. The rsulting system, when combined with appropriate dynamic mass estimation algorithm software, has shown its effectiveness in terms of two desirable characteristics required. required.
A study on detection of composite errors and high precision cutting method by numerical control of two-dimensional circular interpolation in machining centers
Kim, J.S. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 117~126
This paper describes an application step of a
method which measures circular movements in machining centers. The detection of composite errors of circular movements and a high precision cutting method in machining centers were investigated by the analysis of data measured by
method which can detect the rotating angle and is applicable to variable measuring radius. When the error by squareness error and unbalance of position-loop-gain were mixed, the detection method of each error was proposed. Although the errors by squarenss error and backlash compensation were mixed, the errors by squareness error be detected. If the errors by unbalance of position-loop-gain and backlash compensation were mixed, the errors by unbalance of position-loop-gain could not detected. A high precision cutting mehod, which uses the NC program compensated by using feed-back data from error measured by the
method, was proposed.
A study on the PWM type High Speed Electromagnet
C.S. Song ; H.J. Yang ; S.B. Song ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 127~135
This paper is concerned about a high speed electromagnet of Pressure control solenoid valve. Solenoid valve is controlled by means of Pulse width modulation. The magnetostatic field problem on a solenoid is numerically solved by the 2-D axisymmetric finite element method. And permeance method is adopted for analysing the static and dynamic property of solenoid part theoretically. In addition, in this study, experiments on solenoid part were performed in order to measure the magnetic force and plunger displacement. The numerical results coincided with the experimental results. As a result, the magnetic force has the linear relation with displacement of plunger and the primary factors on the performance of PWM type high speed electromagnet are coil resistance, plunger mass, and the length of air gap between plunger and core.
Development of Speed and Precision in the Mass Measurement of Moving Object
Lee, W.G. ; J.W. Chung ; Kim, K.P. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 136~142
This study presents an algorithm and related techniques which could satisfy the important properties of check weighers and conveyor scales. The algorithm of Recursive Least Squares Regression is described for te weighing system simulated as a dynamic model of the second order. Using the model and the algorithm, model parameters and then the mass being weighed can be determined from the step input. The performance of the algorithm is illustrated in digital simulation. Discussions are extended to the development of fast converging algorithm. It turns out that the algorithm shows several desirable features suitable for microcomputer assisted real-time signal processing, which are high precision and stability in noisy environment.
A Study on the Position Control of Electrohydraulic Servo System Using Adaptive Sliding Mode Control
J.H. Hyun ; Lee, C.O. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 143~157
This paper is concerned with the position control of electrohydraulic servo system under parameter variation. An adaptive sliding mode control which uses the direct parameter estimation scheme, is proposed to design a robust controller for fast and accurate control of the system. It is shown that the adaptive sliding mode control algorithm is robust and effective in attaining fast and accurate position control of system under time-dependent parameter variation. It is also shown experimentally that chattering phenomena in a sliding mode control can significantly be reduced by using boundary layer technique, and that new approach in sliding mode control introducing a term proportional to the distance between the current state and the sliding surface in the control law is effective to obtain fast response and to increase stability of the system. Computer simulation on the dynamic performance of the control system is also presented.
An Application of Variable Structure Model Following Adaptive Control Using Time-Varying Sliding Regime to Robot Manipulator with Vertical 3 links
Kim, J.W. ; D.G. Kang ; H.S. Oh ; H.K. Jung ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 158~167
The design concept of varaiable structure control is useful not only to stochasic systems but also to adaptive control systems. The Dynamic equation of vertical three linkage robot was derived. And it was simplyfied according to the scheme of control strategy. And we specify the form of model. Thereafter the error dynamic equation was derived between the real state of the plant and state of the model. Some simulations were performed to control robot manipulator applying the methodology of the variable structure model following adaptive control.
Development of An Optical Surface Roughness Sensor for On-the-Machine Measurement
Kim, H.S. ; S.W. Hong ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 168~178
This paper presents an optical surface roughness sensor developed for intermediate- process measurement on the machine. The light scattering method is adopted for the sensor, which is designed conpact and flexible enough to apply to 'on the machine' measurement of surface roughness. The developed sensor has special features such that it makes use, as the measurement parameter, of the ratio between fluxes of the incident light, and the specularly and partly diffusely reflected light, and that it can adjust the incident light angle. The experimental investigation reveals not only the sensor has good performance as a surface roughness sensor but the sensor is very robust so as to be useful in in-process measurement.
Assessment of cutting performance and chip breaking characteristics with a nondimensional parameter consists of cutting condition and tool shape factor(l) -Orthogonal cutting-
Lee, Y.M. ; Park, W.S. ; S.W. Seo ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 179~184
In this study a nondimensional parameter, feed/land length(F/L) was introduced, and using this parameter, cutting performance and chip breaking characteristics of the groove and the land angle type chip formers were assessed. Specific cutting energy consumed and shape of broken chip with its breaking cycle time were appraised to find out the ranges of F/L value where efficient cutting and effective chip breaking could be achieved. C type chip was found out to be the most preferable in terms of cutting efficiency.
System Development for Automatic Tool Wear Measurement
Kim, Y.I. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 6, 1994, Pages 185~199
This study has been performed to present a new automatic tool wear measurement by digital image processing. The purpose of this paper is to develop an automatic tool wear measuring system based on the image processing which can be applied to the quasi-real time measurement of the characteristics of insert tip in turning. Tool wear monitoring is one of the key-problems, for the development of control systems of modern unmanned factory which are not completely solved now. In oredr words at present complete qualitative and quantitative information on tool wear morphology is required, at least on the following aspects : flank wear, its dimensions and distribution on the maximum and mean values on VB pqrqmeter in the various zones of the wearland. crater wear, its main dimensions and values of KT parameters. This research has been performed to this technique made possible by designing a proper lighting system to the worn tool with following features : The flank wear is measured by observing the active cutting part from a proper direction and by lighting the wearland by a diffuser optic system. The crater wear is visualized by lighting the tool by a He-Ne gas laser system developed in this study. By means of this system it is research to evaluate classical parameters of tool wear and to have complete information about tool wear morphology.