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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 31, Issue 12 - Dec 2014
Volume 31, Issue 11 - Nov 2014
Volume 31, Issue 10 - Oct 2014
Volume 31, Issue 9 - Sep 2014
Volume 31, Issue 8 - Aug 2014
Volume 31, Issue 7 - Jul 2014
Volume 31, Issue 6 - Jun 2014
Volume 31, Issue 5 - May 2014
Volume 31, Issue 4 - Apr 2014
Volume 31, Issue 3 - Mar 2014
Volume 31, Issue 2 - Feb 2014
Volume 31, Issue 1 - Jan 2014
Selecting the target year
An Experimental Study on the Prediction Control Technique for a Magnetic Bearing
Kim, Chae Sil ; Jung, Hoon Hyung ; Shin, Min Jae ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 99~104
DOI : 10.7736/KSPE.2014.31.2.99
Active vibration control methods are required in the high speed rotor systems supported by magnetic bearings. A prediction control technique is one of the control methods. Gain and phase angle are primarily chosen with analyzing the responses for a certain rotor speed. The feasibility of this technique has been reported for only analytical simulations. Therefore this paper constructs the test rig supported by ball bearings with a magnetic bearing type actuator and develops a prediction control system by using LabVIEW and Compact RIO. Finally as rotating speeds are modulated, the gains and phase angles for the speeds are determined with vibration control of the test rig. This leads that the prediction control technique may be applied to the rotor system with the magnetic bearing.
T-S Fuzzy Control of IPMSM using Weighted Integral Action
Hwang, Tae Hwan ; Kim, Tae Kue ; Park, Seung Kyu ; Ahn, Ho Gyun ; Yoon, Tae Sung ; Kwak, Gun Pyong ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 105~112
DOI : 10.7736/KSPE.2014.31.2.105
This paper proposes a novel
T-S Fuzzy controller with a weighted integral action for Interior Permanent Magnet Synchronous Motor(IPMSM) which have nonlinear dynamics. The
T-S Fuzzy controller is used for the robustness of nonlinear systems and the weighted integral action is used for the tracking problem and the improvement of control performance. A T-S Fuzzy controller is designed by combining the local controllers with the overall stability, and LMI(Linear Matrix Inequality)is used to determine the gains of linear controllers. The tracking problem of IPMSM is changed into regulator problem by introducing the integral action and the weighting factor gives flexibility to a
Study on Angle Calculation of Two-axis Manipulator for Laser Assisted Machining
Kim, Dong Hong ; Jung, Dong Won ; Lee, Choon Man ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 113~117
DOI : 10.7736/KSPE.2014.31.2.113
Laser Assisted Machining (LAM) was often used in process of difficulty-to-cut materials. In previous study, Laser assisted machining was a straight path processing using 1-axis manipulator in laser module. But 1-axis manipulator in laser module was able to process only straight path. So, in this study, laser module in laser assisted machining equipped to 2-axis manipulator. 2-axis manipulator has two motors. First motor is machining direction motor and second motor is Vertical Motor. Machining direction motor rotates in the direction of machining and vertical motor rotates vertical direction in the direction of machining. Machining path of laser assisted machining was considered diagonal path and curved path of laser heat source. This study calculated the 2-axis manipulator`s rotation angle in diagonal path and curved path.
A Study on the Development of the Rotary and Linear Laser Modules
Sim, Min-Seop ; Hwang, Seong-Ju ; Kim, Dong-Hyeon ; Lee, Choon-Man ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 119~123
DOI : 10.7736/KSPE.2014.31.2.119
Recently, laser processing technologies have been developed in many different industrial fields. The laser processing technologies are widely being applied such as laser assisted machining, cladding, heat treatment and coating. In the laser modules of the laser assisted machining system, laser lens is very important for accuracy and productivity of product. As the laser beam size, shape and focusing distance change, heat input energy of preheating point can be changed, the laser module of the laser assisted machining system should be equipped with various lenses differing beam size, beam shape and focusing distance. In this study, the rotary and linear laser modules are suggested. The finite element analysis is carried out to certify the static and dynamic stabilities of the developed laser modules. Finally, the rotary and linear laser modules have been fabricated successfully using the analysis results.
Effect of Taper Tension Profiles on Radial Stress of a Wound Roll in Roll-to-roll Winding Process
Lee, Changwoo ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 125~131
DOI : 10.7736/KSPE.2014.31.2.125
Winding is an integral operation in almost every roll-to-roll continuous process and center-winding is suitable and general scheme in the winding system. However, the internal stresses within center-wound rolls can cause damage such as buckling, spoking, cinching, etc. It is therefore necessary to analyze the relationship between taper tension in winding section and internal stress distribution within center-wound roll to prevent the winding failure. In this study, an optimal taper tension control method with parabolic taper tension profile for producing high quality wound roll was developed. The new logic was designed from analyzing the winding mechanism by using the stress model in center-wound rolls. The performance of the proposed taper tension profile was verified experimentally.
A Study on the Method for Improving the Localization Accuracy using the Magnetic Sensors
Kim, Jungtai ; Kim, Moo Sun ; Hong, Jae Sung ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 133~139
DOI : 10.7736/KSPE.2014.31.2.133
Magnetic Sensors can be employed to localize the unmanned vehicle which is running a predefined path where magnets are embedded for certain spaces. Among various sensor types, sensor arrays of 1-dimensional magnetic sensor have the merit of easy elimination of external magnetic component such as terrestrial magnetism. However, interpolation should be considered in the array sensors in order to increase the precision level because there is a limit in arranging sensors in close interval. We propose the novel interpolation method which can be performed with simple computation and represents the improved accuracy by increasing the linearity of the interaction formula. Demonstration of the linearity and simulation results show the proposed method exhibits the improved accuracy compared to the conventional method.
Non-contact Measurement and Analysis of Surface Hardness on Welding Steel using Laser-induced Breakdown Spectroscopy
Kim, Joohan ; Ko, Chansol ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 141~148
DOI : 10.7736/KSPE.2014.31.2.141
In this work, effects of plasma on different hardness of welding steel using laser-induced breakdown spectroscopy were investigated. The ratios of ionic to atomic spectrum peaks were related to its material hardness. The major spectrum peak (Fe) and minor spectrum peak (Mn) were considered as monitoring elements. The stronger repulse plasma was generated, the harder material it was. The ratios of ionic to atomic spectrum peaks increased with respect to the material hardness as well. The correlation of minor spectrum peaks was stronger than that of major spectrum peaks. However, the major spectrum peaks indicated a similar trend, which could be used to estimate the hardness, too. Based on this result, the method could be used as a non-contact remote measurement of material properties.
Output Characteristic of a Flexible Tactile Sensor Manufactured by 3D Printing Technique
Jin, Seung Ho ; Lee, Ju Kyoung ; Lee, Suk ; Lee, Kyung Chang ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 149~156
DOI : 10.7736/KSPE.2014.31.2.149
Flexible tactile sensors can provide valuable feedback to intelligent robots about the environment. This is especially important when the robots, e.g., service robots, are sharing the workspace with human. This paper presents a flexible tactile sensor that was manufactured by direct writing technique, which is one of 3D printing method with multi-walled carbon nano-tubes. The signal processing system consists of two parts: analog circuits to amplify and filter the sensor output and digital signal processing algorithms to reduce undesired noise. Finally, experimental setup is implemented and evaluated to identify the characteristics of the flexible tactile sensor system. This paper showed that this type of sensors can detect the initiation and termination of contacts with appropriate signal processing.
Slip Detection of Robot Gripper with Flexible Tactile Sensor
Seo, Ji Won ; Lee, Ju Kyoung ; Lee, Suk ; Lee, Kyung Chang ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 157~164
DOI : 10.7736/KSPE.2014.31.2.157
In this paper, we design a gripping force control system using tactile sensor to prevent slip when gripper tries to grasp and lift an object. We use a flexible tactile sensor for measuring uniplanar pressure on gripper`s finger and develop an algorithm to detect the onset of slip using the sensor output. We also use a flexible pressure sensor to measure the normal force. In addition, various signal processing techniques are used to reduce noise included in the sensor output. A 3-finger gripper is used to grasp and lift up a cylindrical object. The tactile sensor is attached on one of fingers, and sends output signals to detect slip. Whenever the sensor signal is similar to the slip pattern, gripper force is increased. In conclusion, this research shows that slip can be detected using the tactile sensor and we can control gripping force to eliminate slip between gripper and object.
Characteristics Analysis of Flex Link according to Mold Clamping Force in Injection Molding Machine
Jung, Hyun Suk ; Yoo, Joong Hak ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 165~170
DOI : 10.7736/KSPE.2014.31.2.165
Reproducibility of injection molding machines are studied at the study of this time. We applied computer aided engineering program so it could generate clamping force, about 1,500 kN, to the nozzle center part of flex link in tie-bar and at this time, we made sure condition of stress distribution and transformation quantity in flex link. The result of computer aided engineering transformation quantity was confirmed that transformation of top area was 247~257 kN and bottom areas was 273~279 kN and also was confirmed that the stresses are distributed in a range of 57~750
from top to the bottom of the surface. This time we could confirm the condition of transformation quantity and stress distribution by enforcing the previously used structure analysis of flex link. And we utilized the reference data to establish important point of section for non destructive test overhaul.
Apparent Contact Angle on the Hydrophilic/Hydrophobic Surfaces with Micro-pillars
Yu, Dong In ; Doh, Seung Woo ; Kwak, Ho Jae ; Ahn, Ho Seon ; Kim, Moo Hwan ; Park, Hyun Sun ;
Journal of the Korean Society for Precision Engineering, volume 31, issue 2, 2014, Pages 171~178
DOI : 10.7736/KSPE.2014.31.2.171
In this study, the apparent contact angle on the hydrophilic/hydrophobic surfaces with micropillars was studied. The previous researches showed that the Wenzel equation and the Cassie-Baxter equation were thermodynamically derived for the rough hydrophilic/hydrophobic surfaces and generally referenced on the field of wetting phenomena. For the verification of both equations, the apparent contact angle on the hydrophilic/hydrophobic surfaces with micro-pillars was measured. In the comparison between the measured and estimated apparent contact angles with the equations, the differences between the apparent contact angles were analyzed. Conclusively, the available range and limitation of theoretical equations were investigated and further researches about the apparent contact angle on the rough surfaces were proposed.