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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(2)
C.H. Kang ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 5~17
The Identification of drilling chatter on the machining accuracy
Park, J.K. ; H.G. Seong ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 18~24
Drilling chatter is regenerative type self-excited vibration and can be predicted by the measurments of the dynamic compliance between tool and workpiece based on structural dynamics and cutting dynamics. This paper describes the theoretical prediction about drilling chatter and the mechanism of the formation of multi-coner shape in holes by drilling chatter. By the experiments and theoretical study, it is found that the odd number of multi-coner shape is always generated by drilling chatter.
In-process Monitoring of Milling Chatter by Artificial Neural Network
S.I. Yoon ; Lee, S.S. ; Kim, H.S. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 25~32
In highly automated milling process, in-process monitoring of the malfunction is indispensable to ensure efficient cutting operation. Among many malfunctions in milling process, chatter vibration deteriorates surface finish, tool life and productivity. In this study, the monitoring system of chatter vibration for face milling process is proposed and experimentally estimated. The monitoring system employs two types of sensor such as cutting force and acceleration in sensory detection state. The RMS value and band frequency energy of the sensor signals are extracted in time domain for the input patterns of neural network to reduce time delay in signal processing state. The resultes of experimental evaluation show that the system works well over a wide range of cutting conditions.
Detection of Main Spindle Bearing Conditions in Machine Tool via Neural Network Methodolog
Oh, S.Y. ; Chung, E.S. ; Lim, Y.H. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 33~39
This paper presents a method of detecting localized defects on tapered roller bearing in main spindle of machine tool system. The statistical parameters in time-domain processing technique have been calculated to extract useful features from bearing vibration signals. These features are used by the input feature of an artificial neural network to detect and diagnose bearing defects. As a results, the detection of bearing defect conditions could be successfully performed by using an artificial neural network with statistical parameters of acceleration signals.
An Analytical Investigation on the Ratio of Angular Velocity in Spherical Involute Bevel Gearsets
Park, N.G. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 40~45
The kinematical relationship of bevel gearsets lies at the root of the gear design. As the demand on precision bevel gears is increased in the related industries, the kinematic analysis of a pair of sperical involute bevel gears needs to be exactly evaluated for the computer aided design. Pitch cone angles of bevel gearsets have been calculated under the assumption that the geared system is equivalent to a coned roller system without slipping. But this kinematical model involves some errors in the value of the ratio of angular velocity. In this paper, the ratio of the angular velocity is exactly derived, based on the perfect involute tooth surface. Four nonlinear equations representing the kinematical relationships are numerically solved to obtain the pitch and base cone angles. The ratios of angular volocities according to pressure and shaft angles are calculated and compared with those of the approximate gear model.
Kinematical Investigation and Geometry Modeling of the Perfect Involute Bevel Gearsets
Park, N.G. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 46~56
As demands on the precision bevel gears are increased in the related industry, the exact kinematical investigations of a pair of spherical involute bevel gears are required for the computer aided design. The exact angular velocity ratio based on the characteristics of the spherical involute tooth is derived and verified from the relationship between rotational angles. Elementary kinematics of the gearsets is investigated by applying the transformation of the coordinate systems. The tooth contact lines based on logarithmic tooth-wise curve are examines in three dimentional space. Contact ratio is formulated and simulated according to the system parameters such as shaft angles, pressure angle, and spiral angles. The condition of teeth interference is dervied and the critical numbers of gear teeth are calculated. The whole surface geometry of a spiral bevel gearsets are discretized and visualized by a computer graphic tool.
The Numerical Solution of Time-Optimal Control Problems by Davidenoko's Method
J.S. Yoon ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 57~68
A general procedure for the numerical solution of coupled, nonlinear, differential two-point boundary-value problems, solutions of which are crucial to the controller design, has been developed and demonstrated. A fixed-end-points, free-terminal-time, optimal-control problem, which is derived from Pontryagin's Maximum Principle, is solved by an extension of Davidenko's method, a differential form of Newton's method, for algebraic root finding. By a discretization process like finite differences, the differential equations are converted to a nonlinear algebraic system. Davidenko's method reconverts this into a pseudo-time-dependent set of implicitly coupled ODEs suitable for solution by modern, high-performance solvers. Another important advantage of Davidenko's method related to the time-optimal problem is that the terminal time can be computed by treating this unkown as an additional variable and sup- plying the Hamiltonian at the terminal time as an additional equation. Davidenko's method uas used to produce optimal trajectories of a single-degree-of-freedom problem. This numerical method provides switching times for open-loop control, minimized terminal time and optimal input torque sequences. This numerical technique could easily be adapted to the multi-point boundary-value problems.
A Study on the Electro Discharge Texturing Characteristics of the work Roll for Cold Rolling and Surface Roughgness of Steel Strip
Kim, S.K. ; E.C. Jeon ; T.O. Jun ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 69~76
This paper describes characteristics of EDT(Electro Discharge Texturing) and that the strip surface has influence on the paintability. The pulse mode and the capacitor mode of recently developed EDT method were investigated about the peak shape and the roughness of strip surface. And EDT method compared the above-mentioned contents with the SBT(Shot Blast Texturing) method. The peak count of the pulse mode is more than that of the capacitor mode. But the lower roughness below the Ra 3.2 .mu. m of the strip surface, the texturing time of the pulse mode is longer than the capacitor mode. In SBT method, the peak shape is similar to capacitor mode. But the EDT roll has more uniformity than the SBT roll and has more peak count than that of SBT roll. Therefore, in the painted steel sheet, EDT roll gives better surface of clarity image than the SBT roll.
Drill Wear Modelling based on Motor Current and Application to Real-time Wear Estimation
Kim, H.Y. ; J.H. Ahn ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 77~87
In-process detection of drill wear is one of the most important technoligies for automatic, unmaned machining systems. In this study, an on-line drill wear estimation model based on spindle/Z-axis motor currents generated during the drilling process is proposed. The theoretical model is obtained by integrating the drilling process model and the servomechanism model. The drilling process model describes the relationship of drill wear and drilling torque/ thrust force, whereas the servomechanism model describes the relationship of drilling torque/ thrust force applied to motor and spindle/Z-axis motor current. Evaluation tests have shown that the proposed model is a good real-time estimator for drill wear.
The Characteristic Analysis of Leaf Springs with Large Free Camber and without Spring Eye
S.J. Choe ; H.H. Kwon ; Park, J.C. ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 88~97
The leaf spring is used in the suspension of most buses and trucks due to its compactness, which reduces the shock-force and the vibration from the road, and increases passenger comfortability and carlife. Of the various kinds of leaf springs, the leaf spring without eyes can be found easily in the heavy duty truck, and has different characteristics to the leaf spring with eyes in the case of large free camber. Because of radius change, the leaf without eyes slips on the supports, which makes the deflection. The difference is due to this deflection. In this paper, we show the general method of characteristic analysis, for example, Pandan method, can be no more applicable to these springs. Thus considering the geometry deflection by slip, we have developed the equation of the characteristic of the leaf spring without eyes and prove the effectiveness of this equation by experiment. From the result, at large camber the slip deflection is large and as camber smaller, this is smaller. At the camber behind some value, the effect of slip no longer influence to the characteristic of leaf springs.
Monitoring System for Abnormal Cutting States in the Drilling Operation using Motor Current
Kim, H.Y. ; J.H. Ahn ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 98~107
The in-process detection of drill wear and breakage is one of the most importnat technical problems in unmaned machining system. In this paper, the monitoring system is developed to monitor abnormal drilling states such as drill breakage, drill wear and unstable cutting using motor current. Drill breakage is detected by level monitoring. Tool wear is classified by fuzzy pattern recognition. The key feature for classification of tool wear is the estimated flank wear which is calculated by the proposed flank wear model. The characteristic of the model is not sensitive to the variation of cutting conditions but is sensitive to drill wear state. Unstable cutting states due to the unsmooth chip disposal and the overload are monitored by the variance/mean ratio of spindle motor current. Variance/mean ratio also includes the information about the prediction of drill wear and drill breakage. The evaluation experiments have shown that the developed system works very well.
Real-Time Tension Control in a Multi-Span Continuous Process System
K.H. Shin ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 108~116
A tension control strategy for a multi-span web transport system is proposed. This strategy is developed by using the tension transfer phenomena in multi-span systems. The performance of this control strategy is compared with that of an existing control strategy through a computer simulation. A real-time software is designed based on the proposed tension control stration of master speed drive in tension control is demonstrated.
Robust control design for robots with uncertainty and joint-flexibility
M.C. Han ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 117~125
An improved robust control law is proposed for uncertain rigid robots. The uncertainty is nonlinear and (possibly fast) time-varying. Therefore, the uncertain factors such as imperfect modeling, friction, payload change, and external disturbances are all addressed. Based on the possible bound of the uncertainty, the controller is constructed. For uncertain flexible-joint robots, some feedback control terms are then added to the proposed robust control law in order to stabilize the elastic vibrations at the joints. To show that the proposed control laws are indeed applicable, the stability study based on Lyapunov function, a singular perturbation approach, and simulation results are presented
Analysis of Acoustical Performance of Exhaust System by Lattice Filter
W.G. Hwang ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 126~135
An exhaust muffler is one of the simple and effective means to meet the demand for a quiet vehicle, and it deserves a close attention to effectively reduce the engine noise. The transfer function technique is one of the tools that have been used to analyze the noise characteristics of the exhaust muffler. In this paper we obtained a transfer function using the forward-going and backward-going components of sound pressure in the exhaust muffler, which is compatible wiht lattice filter algorithm. This form of transfer function is obtained for the basic elements of a muffler, such as uniform tube, open termin- ation, closed termination, anechoic termination, expansion, contraction, extended-tube resonator, hole, Helmholtz resonator, and concentric hole-cavity resonator. The results are combined to produce the transfer function of various types of mufflers. With this transfer function we calculate the transmission and insertion losses of mufflers, and examined the effects of various design parameters. Comparisons were made between the calculation and experimental results, which showed a good agreement, and we conclude that the transfer function of lattice form can be used to analyze the noise characteristics of the exhaust mufflers.
Development of a Parametric Simulation Model by a Model Integration Method for Production System with Robots
K.H. Kuk ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 136~148
In this study, a model integration method is pressented as a new method for development of a parametric simulation model. This method enable us to integrate the special simulation models for each production subsystem into a large simulation model. Not only this large simulation model but also each special simulation model for each production subsytem can be used independently. Using this integration method man can reduce the development time and cost for simulation model development. To show the usefulness of this method, a simulation model for a production system with robots is developed by this model integration method. This simulation model is realized by the integration of two special simulation models, one model for a machining subsystem and the other model for a transport subsystem. The modeled production system consists of the robotic cells for machining and a transport subsystem which enable the material flow among the robotic cells. The flow of workpiece in each robotic cell is not fixed. All machines in a robotic cell are only served by robots.
A Study on the Kinematic Analysis of a 6-DOF Parallel Robot Manipulator
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 149~156
Nonlinear System Identification; Comparison of the Traditional and the Neural Networks Approaches
K.T. Chong ;
Journal of the Korean Society for Precision Engineering, volume 12, issue 5, 1995, Pages 157~165
In this paper the comparison between the neural networks and traditional approaches as nonlinear system identification methods are considered. Two model structures of neural networks are the state space model and the input output model neural networks. The traditional methods are the AutoRegressive eXogeneous Input model and the Nonlinear AutoRegressive eXogeneous Input model. Computer simulation for an analytic dynamic model of a single input single output nonlinear system has been done for all the chosen models. Model validation for the obtained models also has been done with testing inputs of the sinusoidal, ramp and the noise ramp.