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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 30, Issue 12 - Dec 2013
Volume 30, Issue 11 - Nov 2013
Volume 30, Issue 10 - Oct 2013
Volume 30, Issue 9 - Sep 2013
Volume 30, Issue 8 - Aug 2013
Volume 30, Issue 7 - Jul 2013
Volume 30, Issue 6 - Jun 2013
Volume 30, Issue 5 - May 2013
Volume 30, Issue 4 - Apr 2013
Volume 30, Issue 3 - Mar 2013
Volume 30, Issue 2 - Feb 2013
Volume 30, Issue 1 - Jan 2013
Selecting the target year
Development of Condition Monitoring System for Reduction Unit of High-speed Rail
Lee, Dong-Hyong ; Kwon, Seok Jin ; Park, Byoung-Su ; Cho, Duk-Young ; Kim, Jin-Woo ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 667~672
DOI : 10.7736/KSPE.2013.30.7.667
This paper presents the development of a condition monitoring system that monitors the operating conditions of a reduction unit, such as the bearing temperature, gearbox vibration, and gear oil deterioration, and notifies the operator of potential problems or abnormal conditions. A series of field tests on high-speed rail and conventional lines was performed to identify the characteristics of temperature rise and vibration levels on the reduction unit during operation. The monitoring system was designed based on the proper sensor selection, measurement method, and signal analysis to optimize the interface with the operating system of high-speed trains. Application of this monitoring system to high-speed trains will play an important role in their proper maintenance and safe operation.
Wireless Temperature Monitoring of Driving Gear Unit in High Speed Train Using IC Sensor
Kwon, Seok Jin ; Seo, Jung-Won ; Lee, Dong-Hyong ; Hwang, Ji Sung ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 673~678
DOI : 10.7736/KSPE.2013.30.7.673
Driving gear units can be affected by various problems, including those associated with external or internal defects in the bearing, problems with the lubricant oil, high-loading of the railway, and frequent impacts generated by rail joints. Temperature monitoring is a basic method in diagnosing abnormal conditions in the reduction gear and other components. This paper describes a new wireless monitoring system for the temperature diagnosis of abnormal conditions of the reduction gear. Integrated circuit (IC)-type temperature sensors were installed in the reduction gear box of a high-speed railway car. The temperature data from the reduction gear were acquired and analyzed in situ during high-speed rail operation. Analysis of these data was used to alert the driver and/or maintenance personnel when problems occurred.
Analysis of Vibration Parameters for the Fault Diagnosis of Reduction Unit for High-speed Train
Kim, Jae Chul ; Ji, Hae Young ; Lee, Kang Ho ; Moon, Kyung Ho ; Seo, Jung-Won ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 679~686
DOI : 10.7736/KSPE.2013.30.7.679
The reduction unit is one of the most important components in railway cars, due to the transmission of torque from the motor to the wheels. Faulty reduction gears in high-speed trains result from excessive wear on the gear or damage to the gear. These types of gear defects have a significant effect on high-speed rail operation and safety; thus, a diagnosis system for the reduction unit is needed. Vibration diagnosis technology is one of the most effective diagnostics. In this paper, the vibration parameters of a reduction unit were evaluated during a driving-gear test and a full-vehicle test, using kurtosis and the crest factor. These tests were performed under normal operating conditions; a specimen tester was used to diagnose problems in defective gears.
Development of Thermal Monitoring System for Inspection of Railway Components
Seo, Jung-Won ; Kwon, Seok Jin ; Kim, Hyeong-Jin ; Lee, Chan-Woo ; Kim, Min-Su ; Ham, Young-Sam ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 687~693
DOI : 10.7736/KSPE.2013.30.7.687
The service conditions of railway cars have become more difficult in recent years due to increased speed. Faulty components in the railcars may result in service interruption, or in extreme cases, derailment. Thus, it is important to diagnose and monitor the main components of railcars. Temperature monitoring is one of the basic methods used to diagnose abnormal conditions in the main components of railway cars, such as in bearings, reduction gears, and traction motors. In this study, we developed a monitoring system for the main components, using an infrared thermography technique. This technique has the advantage of infrared thermal camera imaging of temperature contours in the components. Various hardware and software components of the monitoring system are used to acquire the sensor data, to identify potential problems in railcar operation.
Analysis on the Vibration Characteristics of Reduction Gear Units for High-speed Trains
Moon, Kyung Ho ; Lee, Dong-Hyong ; Kim, Jae Chul ; Ji, Hae Young ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 694~701
DOI : 10.7736/KSPE.2013.30.7.694
The gear-reduction units of Korean high-speed trains consist of a motor reduction unit, an axle gear box reduction unit, and a tripod joint shaft. A reduction gear unit is a gearbox used to reduce the rotational speed of the input shaft to a slower rotational speed on the output shaft. This reduction in output speed helps to increase torque. Defective reduction gear units in high-speed trains are caused by damage to the gear or by gear fatigue. To diagnose potential problems, it is important to know the vibration characteristics of the reduction gear units. In this study, we analyzed the vibration characteristics of reduction gears under various conditions. The test setup included a full-scale test rig to evaluate reduction gear under both normal and extreme operating conditions.
A High-Speed White-Light Scanning Interferometer for Bump Inspection of Semiconductor Manufacture
Ko, Kuk Won ; Sim, Jae Hwan ; Kim, Min Young ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 702~708
DOI : 10.7736/KSPE.2013.30.7.702
The white-light scanning interferometer (WSI) is an effective optical measurement system for high-precision industries (e.g., flat-panel display and electronics packaging manufacturers) and semiconductor manufacturing industries. Its major disadvantages include a slow image-capturing speed for interferogram acquisition and a high computational cost for peak-detection on the acquired interferogram. Here, a WSI system is proposed for the semiconductor inspection process. The new imaging acquisition technique uses an 'on-the-fly' imaging system. During the vertical scanning motion of the WSI, interference fringe images are sequentially acquired at a series of pre-defined lens positions, without conventional stepwise motions. To reduce the calculation time, a parallel computing method is used to link multiple personal computers (PCs). Experiments were performed to evaluate the proposed high-speed WSI system.
Design of Link-type Thumb Rehabilitation Robot for Finger Patients
Kim, Hyeon Min ; Kim, Gab Soon ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 709~716
DOI : 10.7736/KSPE.2013.30.7.709
Rehabilitation of finger patients requires that the patients exercise their hands and fingers for proper functioning to return. A thumb rehabilitation robot, equipped with a two-axis force sensor, can prevent injury to the thumb by monitoring the applied pulling force. In this paper, we describe a link-type thumb rehabilitation robot designed for patients' thumb rehabilitation exercise. Tests of the manufactured link-type thumb rehabilitation robot were performed on normal male patients. Our results show that the robot can be used for flexibility and muscle-strength rehabilitation exercises for a patient's thumb.
An Improved Input Shaping Method for Precise Stopping and Residual Vibration Reduction of Cranes
Bae, Gyu-Hyun ; Hong, Seong-Wook ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 717~724
DOI : 10.7736/KSPE.2013.30.7.717
Industrial cranes are indispensable equipment in heavy industry. However, unwanted vibrations in cranes often cause accidents. Input shaping is widely accepted as a useful tool for removing residual vibration in cranes. A unity magnitude zero vibration (UMZV) input shaper is often used for cranes driven by on-off-type motors. However, although a UMZV input shaper minimizes residual vibration, the input shaper cannot prevent the crane from moving slightly further than expected from the original command. This paper describes an improved method of input shaping that can compensate for position inaccuracies, as well as remove the residual vibration of cranes. Experiments were performed to validate the proposed input-shaping method, illustrated through numerical simulations.
Development of a Torque Distribution Algorithm for Improving Stability and Mobility of the Wall-climbing Robot Platform (ROPE RIDE) Equipped with Triangular Track Wheels
Cho, Sunme ; Seo, Kunchan ; Kim, Taegyun ; Kim, Jongwon ; Kim, Hwa Soo ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 725~732
DOI : 10.7736/KSPE.2013.30.7.725
This paper presents a torque distribution algorithm for improving the stability and mobility of a wall-climbing robot platform. During ascent, the pitch moment caused by the payload or external disturbances separates the robot's triangular tracks from the wall, significantly deteriorating its stability. Moreover, the reaction forces stemming from the increase in the pulling force may degrade the robot's mobility. Thus, it is very important to minimize the reaction forces acting on the triangular tracks, as well as the fluctuations in the pulling force, during the climb. Through dynamic modeling of the proposed robot platform, we demonstrated the dependence of the robot's stability and mobility on the torque distribution of the triangular tracks. Extensive simulations using different climbing speeds were used to significantly improve the stability and mobility of the proposed robot platform.
Effect of Process Parameters in Electromagnetic Forming Apparatus on Forming Load by FEM
Noh, Hak Gon ; Park, Hyeong Gyu ; Song, Woo Jin ; Kang, Beom Soo ; Kim, Jeong ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 733~740
DOI : 10.7736/KSPE.2013.30.7.733
The high-velocity electromagnetic forming (EMF) process is based on the Lorentz force and the energy of the magnetic field. The advantages of EMF include improved formability, wrinkle reduction, and non-contact forming. In this study, numerical simulations were conducted to determine the practical parameters for the EMF process. A 2-D axis-symmetric electromagnetic model was used, based on a spiral-type forming coil. In the numerical simulation, an RLC circuit was coupled to the spiral coil to measure various design parameters, such as the system input current and the electromagnetic force. The simulation results show that even though the input peak current levels were at the same level in each case, the forming condition varied due to differences in the frequency of the input current. Thus, the electromagnetic forming force was affected by the input current frequency, which in turn, determined the magnitude of the current density and the magnetic flux density.
Development of Flexible Packing Ring in Steam Turbine for Reduction of Leakage by using CFD Flow Analysis
Kim, Jin Hyung ; Bae, Jun Ho ; Lee, Chang-Ryeol ; Kim, Chul ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 741~748
DOI : 10.7736/KSPE.2013.30.7.741
A conventional packing ring was designed with a large clearance to prevent damage due to the vibration of the rotor, which can lead to an increase in steam leakage. In this study, a flexible packing ring using winding springs was developed to prevent damage to the rotor teeth by minimizing vibration, while maintaining a smaller clearance than that of conventional rotor designs. Theoretical analysis and finite element analysis (FEA) were used to design the winding spring to satisfy the specified allowable stress limit and minimum load requirements. The shape of the winding spring was designed by applying curves to the center and end parts of a flat spring. Computational fluid dynamics (CFD) analysis was used to predict the leakage of the flexible packing ring. Flow rate measurement tests were performed to verify the leakage reduction efficiency and the reliability of the CFD analysis.
The Lubrication Characteristics According to the Rotating Radius of Piston in a Swash-Plate Type Piston Pump
Cho, Ihn Sung ; Jung, Jae Youn ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 749~753
DOI : 10.7736/KSPE.2013.30.7.749
Hydraulic systems are used to transform mechanical energy and fluid energy into each other. Its applications are very wide over the whole industries such as automobiles, public works, rockets, machine tools, construction heavy equipments, airplaces and so on. They are hydraulic pumps that transform energy in the systems. In this study, with basic operation principles as a start point, I tried to understand how the rotating radius of a piston affects the lubrication characteristics in more practical conditions, a swash-plate with tilt angle zero capable of rotating motion and other devices was used. In this paper, a slipper was located on 45mm eccentricity from the center of a swash-plate. As a result, through this experiment, it was found that the rotating radius of a piston affects load capacity, leakage flow and lubrication characteristics and it is one of the important parts for improving the pump efficiency.
Investigation of the Thermal Mode-based Thermal Error Prediction for the Multi-heat Sources Model
Han, Jun An ; Kim, Gyu Ha ; Lee, Sun-Kyu ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 754~761
DOI : 10.7736/KSPE.2013.30.7.754
Thermal displacement is an important issue in machine tool systems. During the last several decades, thermal error compensation technology has significantly reduced thermal distortion error; this success has been attributed to the development of a precise, robust thermal error model. A major advantage of using the thermal error model is instant compensation for the control variables during the modeling process. However, successful application of thermal error modeling requires correct determination of the temperature sensor placement. In this paper, a procedure for predicting thermal-mode-based thermal error is introduced. Based on this thermal analysis, temperature sensors were positioned for multiple heat-source models. The performance of the sensors based on thermal-mode error analysis, was compared with conventional methods through simulation and experiments, for the case of a slide table in a transient state. Our results show that for predicting thermal error the proposed thermal model is more accurate than the conventional model.
Effect of Muscle Function and Muscular Reaction of Knee Joint in the Twenties on the Whole Body Vibration Exercise
Kang, Seung Rok ; Jeong, Gu Young ; Bae, Jong Jin ; Min, Jin Young ; Yu, Chang Ho ; Kim, Jung Ja ; Kwon, Tae Kyu ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 762~768
DOI : 10.7736/KSPE.2013.30.7.762
This study investigated the effect of whole-body vibration on muscle function and muscular reaction in the knee joint. We recruited thirty healthy subjects and divided them into a training group, who experienced whole-body vibration, and a control group, who did not. The training group performed whole-body vibration exercises for 30 min per day, 3 days a week, for 8 weeks. We measured knee joint torque to estimate muscle strength and reaction, using BIODEX System 3. Knee joint peak torque and total work performed increased significantly in the training group, and muscle acceleration time decreased. These results suggest that stimulation by whole-body vibration can improve muscle strength and reaction by improving muscle tone and increasing blood temperature and flow speed in muscular fiber. Our results also indicate that 4 weeks of exercise with whole-body vibration is required to improve the reaction response, and six weeks to improve strength.
Design of Carbon Composite Prosthetic Feet using Finite Element Methods
Cho, Hyeon Seok ; Cha, Gook Chan ; Park, Jin Kook ; Kim, Shin Ki ; Lee, Suk Min ; Mun, Mu Sung ; Kim, Chang Bu ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 7, 2013, Pages 769~776
DOI : 10.7736/KSPE.2013.30.7.769
The dynamic compliance characteristics of a prosthetic foot midgait are very important for natural performance in an amputee's gait and should be in a range that provides natural, stable walking. In this study, finite element analysis (FEA) and classical laminate theory were used to examine the mechanical characteristics of a carbon-epoxy composite laminate prosthetic foot as a function of variation in the lamination composition. From this analysis, an FEM model of a prosthetic keel, made from the composite material, was developed. The lamination composition of the keel was designed for improved stiffness. The prototype product was fabricated using an autoclave. Vertical loading response tests were performed to verify the simulation model. The results of the experiments were similar to those from simulations below the loading level of the gait, suggesting use of the proposed simulation model for prosthetic keel design.