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Volume 33(9); September 2016

Articles
A Study on the Development of System for the Micro-Volume Samples Analysis
Sang Wook Lee, Jin Ho Lee
J. Korean Soc. Precis. Eng. 2016;33(9):699-706.
Published online September 1, 2016
Assay of biomolecules based on absorption spectroscopy is a sensitive, minute, quantitative, rapid and real-time process. UV-vis spectrometry has inherent advantages for use in analytical applications. To reduce the consumption of scarce samples, a new generation of miniaturized UVvis spectrometric systems has been developed. This study determined empirically and through simulations the feasibility of assaying biomolecules by means of UV-vis spectrometry. This paper also reports a fully integrated portable micro-detection equipment system that utilizes a microoptical path for analysis of micro-volume samples.
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Study on Analysis of Vibration Characteristics and Modal Test for a Quad-Rotor Drone
Minsong Kim, Jaenam Kim, Youngseop Byun, Jeong Kim, Beomsoo Kang
J. Korean Soc. Precis. Eng. 2016;33(9):707-714.
Published online September 1, 2016
This paper describes analysis results of vibration characteristics and modal test for a small-scale quad-rotor drone. The rotor arm has a slender body with a propeller and motor at its tip. Rotor system generates excitation for an unbalanced mass. Therefore, the drone platform is involved in the possibility of resonance. For advance identification of the possibility of resonance, confirmation of eigen-mode being closest to the propeller operation range is necessary. Material properties of CFRP tubes used for the rotor arm were acquired by finding the natural frequency based on Rayleigh method. A simplified quad-rotor FE model consisting of rotor arm assembly with tip mass was built to perform numerical analysis, and a free-free boundary condition was applied to provide flight status. Modal tests for the actual platform with impact hammer instrument were performed to verify analysis results. Separation margin from hazardous eigen-mode was checked on the propeller operation range.
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Classification Performance Analysis of Silicon Wafer Micro-Cracks Based on SVM
Sang Yeon Kim, Gyung Bum Kim
J. Korean Soc. Precis. Eng. 2016;33(9):715-721.
Published online September 1, 2016
In this paper, the classification rate of micro-cracks in silicon wafers was improved using a SVM. In case Ι, we investigated how feature data of micro-cracks and SVM parameters affect a classification rate. As a result, weighting vector and bias did not affect the classification rate, which was improved in case of high cost and sigmoid kernel function. Case II was performed using a more high quality image than that in case I. It was identified that learning data and input data had a large effect on the classification rate. Finally, images from cases I and II and another illumination system were used in case III. In spite of different condition images, good classification rates was achieved. Critical points for micro-crack classification improvement are SVM parameters, kernel function, clustered feature data, and experimental conditions. In the future, excellent results could be obtained through SVM parameter tuning and clustered feature data.
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Design and Implementation of the Cable Rod Hydraulic Actuator for Robotic Revolute Joints
Jungyeong Kim, Sangdeok Park, Jungsan Cho
J. Korean Soc. Precis. Eng. 2016;33(9):723-730.
Published online September 1, 2016
This paper presents a cable-driven hydraulic actuator named Cable Rod Hydraulic Actuator (CRHA). The cable actuating system is attractive for designing a compact joint in robotic applications since it can be installed remotely from the joint. Recently, cable rods have been used in pneumatic area for inertia reduction. However, designing cable rods in hydraulics is challenging because it is difficult to achieve flexibility and endurance simultaneously under high pressure conditions. In this paper, the cable rod, which consists of a cable and jacket, is proposed to meet both requirements. To design the CRHA, we determined the design parameters, such as cylinder size, and selected the cable rod’s material by friction and leakage test. Finally, comparisons experiments about step and frequency responses with conventional hydraulic actuators were performed to assess feasibility for robotic joints, and the results show that the proposed system has good bandwidth and fast response as robotic joints.
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Cabinet Design for Vibration Reduction of a Drum Type Washing Machine
Seung Ji Yong, Kwon Hee Kim, Young Gwan Kim
J. Korean Soc. Precis. Eng. 2016;33(9):731-737.
Published online September 1, 2016
In the quest for improved capacity and accelerated dehydration speed of drum type washing machines, an increase in vibration emerges as a major challenge. In an attempt to derive a new design with reduced vibration, a full finite element model of washing machine has been developed, with experimental verification. After modal analyses of several design variants, a new design of the cabinet has been proposed. Forced vibration analysis of the new model suggests that 19% reduction in cabinet vibration amplitude can be achieved with this design.
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Experimental Study on the Fatigue Strength of a Running Equipment in Railway Applications
Sung Cheol Yoon, Jeongguk Kim
J. Korean Soc. Precis. Eng. 2016;33(9):739-744.
Published online September 1, 2016
The truck that is used as running equipment for tank freight car support is a core structural part that supports the load of the car body and significantly influences the safety of freights and vehicles, as well as their running performance. Running equipment is composed of truck frames, wheels and wheel axles, independent suspensions, and brakes. Among these components, the truck frame supporting the load of the vehicles and freights may be the most important component. This study was carried out to analyze the structure of truck frames and to determine whether they are safe when the maximum vertical load, braking part load, and the front and rear load are applied to truck frames. This was achieved by subjecting the truck frames to stress tests and then measuring the stress on each part. The results of the stress tests showed that truck frames have a safe vehicle load design.
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A Study on the Acceleration and Deceleration Control of Free-Form Surfaces
Dae Kyun Baek, Seung-Han Yang
J. Korean Soc. Precis. Eng. 2016;33(9):745-751.
Published online September 1, 2016
This paper presents the acceleration and deceleration control of free-form surfaces. A rapid variation of acceleration (or Deceleration) drives the system into a machine shock, resulting in the inaccuracy of the path control of the NURBS curve. The pattern of acceleration control can be established using the curvature of the NURBS curve. The curvature can be easily calculated from the first and second derivative of the NURBS curve used in Taylor’s expansion for NURBS interpolation. However, the derivatives are not used in the recursive method for NURBS interpolation. Hence, we attempted the difference-derivatives for calculating the NURBS curvature. Both, Taylor’s expansion and the recursive method, are used jointly for controlling the acceleration in the same interpolation algorithm.
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Muscle Activity Analysis of Lower Limb Training for Early Rehabilitation Cycling System in Supine Position
Sun Hye Shin, Shin Bae Seo, Mi Yu, Ho Chon Jeong, Kwang Soo Cho, Jung Pyo Hong, Chul Wn Hong, Tae Kyu Kwon
J. Korean Soc. Precis. Eng. 2016;33(9):753-760.
Published online September 1, 2016
This study was undertaken to develop a bed-type cycling system of lower limbs for rehabilitation. This system consists of two modes of cycling: active and passive. Different velocity and loads are provided for improving the muscle function recovery and increasing the muscular strength. To analyze the muscle activity pattern, we measured muscular activity of lower limbs in the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), medial gastrocnemius (MG), and soleus (SOL), while cycling in the supine position, and based on the pedaling direction. A total of 18 young and 23 elderly, healthy subjects participated in this study. Muscle activity of MG muscles was significantly different in the two age groups. This study could provide the reference data to develop cycling exercises for lower limbs during rehabilitation of the elderly patients.
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Structural Analysis of the Gait Rehabilitation System of a Rail Type for Body-Weight Support Function
Jae Jun Kim, Kyung Kim, Young Soo Seo, Jae Won Kim, Je Nam Kim, Wu Suk Chong, Chang Ho Yu, Tae Kyu Kwon, Won Kyung Song
J. Korean Soc. Precis. Eng. 2016;33(9):761-768.
Published online September 1, 2016
Weight bearing is effective during rehabilitation of gait, in the elderly and disabled people. Various training devices using weight bearing function were developed along with treadmill walking; however, no device has been developed in conjunction to walking on the ground. Here, we designed a rail type frame of a gait rehabilitation system for body-weight support (BWS) function, and analyzed its mechanical safety in the static weight bearing condition of a vertical axis. Computational simulations were performed to analyze structure of the driving parts, which are connected with a rail and driving rollers and the lower plate of the BWS. Structural analyses showed the drivers and BWS were safe, when simulated at 135kg weight under static conditions. Thus, this rail type rehabilitation system can be used for gait training of the elderly and disabled.
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Development of a Sealing-Type Abutment for Implant and the Performance Evaluation via Structural Analysis
Jeong Min Kim, Dae Sun Hong
J. Korean Soc. Precis. Eng. 2016;33(9):769-775.
Published online September 1, 2016
Currently, dental implants are widely used as artificial teeth due to their good chewing performance and long life cycle. Generally, a dental implant consists of an abutment as the upper part and a fixture as the lower part. When chewing forces are repeatedly applied to a dental implant, a gap is often generated at the interfacial surface between the abutment and the fixture, and it results in some deterioration such as loosening of the fastening screw, dental retraction and fixture fracture. To enhance the sealing performance for coping with such problems, this study proposes a new sealing-type abutment having a number of grooves along the conical surface circumference, and it carries out finite element analysis in consideration of the external chewing force and pretension between the abutment and the fixture. The result shows that the proposed sealing-type abutment shows an enhanced sealing performance in terms of the contact pressure in comparison with a conventional abutment.
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한국정밀공학회지 Vol.33 No.9 목차
J. Korean Soc. Precis. Eng. 2016;33(9):778-779.
Published online September 1, 2016
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