• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.45-50
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• 2000

While braking cars, a large amount of energy is taken into the brake system in a short period of time. This leads to some problems ; cracking of the disc, non-uniform wear of pad and disc, fade. Thus it is important to measure the contact thermal behaviour precisely between disc and pad. The measurements must be considered to design the brake system. The paper describes methods to analysis the problem of the thermal behavior on the ventilated disc with ANSYS-a program of FEA and a brake dynamometer. According to this way, the paper can present the error between the data by the dynamometer and the results of analysis by ANSYS.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.249-254
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• 2000

The contact forces between die components for the drawing of large size automotive panels introduce elastic deflections of the die components. Due to the deflections, the gap between blank holder and die varies locally resulting in nonuniform material flow. Such a nonuniform die gap usually requires correcting operation, so called die spotting, which is time consuming trial and error process. To reduce the die spotting time, the optimization of the blank holder bending deflection is needed. In this paper, we implemented an analysis procedure to predict the blank holder deflection. The analysis procedure and design of experiments techniques are applied to the optimization of balance block heights. The optimization results can be used as guidelines in actual die spotting process.

• 한국공작기계학회논문집
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• 제13권2호
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• pp.61-68
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• 2004

A non-contact precision measurement system is a theodolite system, a laser tacker and a photogrammetry system etc. Nowadays, the system reaches to a limit of measurement accuracy required from industrial product of middle and large scale. The one of the solutions for this problem is to maximize the accuracy of the existing measurement system. According to it we performed the study far a measurement accuracy of theodolite system when the distance between two theodolites is changed 1m to 5m. We could blow that the changes of distance affect the measurement accuracy of theodolite system and that the maximum measurement accuracy is $\pm$ 0.02 mm on theodolite distance 3∼4 m.

• 한국생산제조학회지
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• 제23권6호
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• pp.624-629
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• 2014

The purpose of this study is to carry out the task of engine hesitation which occurred intermittently in driving due to the defective CKPS of LPI vehicles. As the result of the wrong data from the equipment of D-logger, the signal error of CKPS caused the engine hesitation. We performed a study in the followings to analyze and investigate the cause effectively. First, we have investigated the control wiring harness and connector pin contact defect inspection. Second, we have inspected the defection of CKPS separately. From this study, it was found that the engine hesitation were caused by the bad durability and we have showed how to diagnosis the fault of the engine hesitation intermittently while driving. Therefore, it is determined that we have to improve the durability of the CKPS through a strict quality control and to increase the reliability.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.700-703
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• 2003

The test method of ASTM E 756 and KS D 0076 to estimate vibration-damping properties is compared. Comparison method depending on specimen support, exciting method and calculation method for loss factor is used. Half-power bandwidth method and vibration decay method is used in the calculation method for loss factor, and Young's modulus is decided by geometric character and density for specimen and resonance frequency. Vibration measurement sensor is compared by using non-contact displacement detector, velocity detector and accelerometer. This paper is also presented the matter which is able to cause error in the measurement

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.544-545
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• 2012

In recent years, vehicle manufacturers have steadily developed fuel saving technologies such as multi-speed automatic transmission. With such a background, the Hyundai-powertech have developed the new 6-speed rear wheel drive(RWD)automatic transmission for FR vehicles. Despite having six-speed, it has the same number of planetary gears as a previously used five-speed automatic transmission and fewer brakes and one-way clutches than the 5 A/T, meaning that it is light, compact, and inexpensive. But, in addition to meshing this internal and external gear simultaneously and phase difference by the tooth contact point and the time difference occurs asymmetric and symmetric sideband noise and vibration caused by the modulation in the vehicle. In this paper presents a method for the design of the carrier phase difference by developing various theories and experiments for gear noise.

• Current Optics and Photonics
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• 제4권5호
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• pp.411-420
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• 2020

Non-contact three-dimensional (3D) measuring technology is used to identify defects in miniature products, such as optics, polymers, and semiconductors. Hence, this technology has garnered significant attention in computer vision research. In this paper, we focus on shape from focus (SFF), which is an optical passive method for 3D shape recovery. In existing SFF techniques using interpolation, all datasets of the focus volume are approximated using one model. However, these methods cannot demonstrate how a predefined model fits all image points of an object. Moreover, it is not reasonable to explain various shapes of datasets using one model. Furthermore, if noise is present in the dataset, an error will be generated. Therefore, we propose an algorithm based on polynomial regression analysis to address these disadvantages. Our experimental results indicate that the proposed method is more accurate than existing methods.

• 소음진동
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• 제2권1호
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• pp.49-59
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• 1992

The motion analysis of a translation device driven by a piezoelectric actuator is performed to identify the mechanics of impact drive mechanism and to find the maximum speed waveform. The translation device is modeled as a semidefinite two-degree-of-freedom system. The motion analysis includes effects of friction force between moving mass and contact surface, dynamics of voltage amplifier and piezoelectric elements, and hysteresis of piezoelectric actuator. Base on the model, simulation studies are carried out and then compared with experimental results. It is found that the error between moving distances obtained by analysis and experiment is less than 15% and that the actual motion of moving mass is well predicted by the analytical work, finally, precision positioning experiments are carried out by using a proximity sensor as a feedback sensor. Position control of moving mass is initiated by the maximum speed waveform and finely tuned by the scaled down waveform so that accurate positioning is accomplished within the resolution of the sensor.

• 대한기계학회논문집
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• 제13권3호
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• pp.443-450
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• 1989

본 연구에서는 공작기계 생산 현장에서 직접적으로 이용될 수 있는 측정시스 템의 개발을 목표로 이제까지 이론적으로 제안된 스핀들 정밀도 측정방법을 종합 분석 하여 디지틀 측정의 기본이론을 정립하고 이를 기반으로 마이크로 컴퓨터를 이용한 측정시스템을 실계 제작하였다.또한 실험을 통하여 본 연구에서 제안된 측정 시스 템의 성능을 기존의 애널로그 측정방법과 비교 검토함으로써 본 방법의 우수성 및 제한점을 실증적으로 입증하고자 하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.439-442
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• 2003

The test method of ASTM E 756 and JIS G 0602 to estimate vibration-damping properties is presented. Measurement method depending on specimen support, exciting method and calculation method for loss factor is used. Half-power bandwidth method and vibration decay method is used in the calculation method for loss factor, and Young's modulus is decided by geometric character and density for specimen and resonance frequency. Vibration measurement sensor is compared by using non-contact displacement detector, velocity detector and accelerometer. The cause of measurement error is also presented.