• 한국정밀공학회지
• /
• 제30권7호
• /
• pp.667-672
• /
• 2013

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.

• 산업경영시스템학회지
• /
• 제37권4호
• /
• pp.12-23
• /
• 2014

The O&M (Operation and Maintenance) phase of offshore plants with a long life cycle requires heavy charges and more efforts than the construction phase, and the occurrence of an accident of an offshore plant causes catastrophic damage. So previous studies have focused on the development of advanced maintenance system to avoid unexpected failures. Nowadays due to the emerging ICTs (Information Communication Technologies) and sensor technologies, it is possible to gather the status data of equipment and send health monitoring data to administrator of an offshore plant in a real time way, which leads to having much concern on the condition based maintenance policy. In this study, we have reviewed previous studies associated with CBM (Condition-Based Maintenance) of offshore plants, and introduced an algorithm predicting the next failure time of the compressor which is one of essential mechanical devices in LNG FPSO (Liquefied Natural Gas Floating Production Storage and Offloading vessel). To develop the algorithm, continuous time Markov model is applied based on gathered vibration data.

• 한국지능시스템학회논문지
• /
• 제24권1호
• /
• pp.96-101
• /
• 2014

풍력은 전 세계적으로 가장 각광을 받고 있는 신재생 에너지이며 당분간 이러한 추세는 계속될 것으로 기대되고 있다. 최근 풍력발전시스템의 O&M(Operation & Maintenance) 비용의 절감에 대한 필요성이 꾸준히 대두되고 있는 실정이다. O&M 비용의 절감을 위한 가장 효율적인 방법은 CMS(Condition Monitoring System)의 도입이며 이는 풍력발전기 부품들의 악화, 적절한 선제적 유지보수, 발전중지시간의 단축 및 궁극적으로 풍력발전기의 운전 효율을 증대시키는 것을 가능케 한다. 풍력발전기의 터빈 로터와 관련하여 질량 불평형 및 공력비대칭과 같은 고장이 발생될 수 있다. 일반적으로 이러한 고장은 다양한 형태의 진동을 야기 시킨다. 이에 본 연구에서는 진동신호에 대한 스펙트럼과 간단한 max-min 진단 로직으로 구성된 고장검출 알고리즘을 제안한다. 또한 제안된 진단기법의 유용성의 확인을 위해 GH-Bladed 프로그램을 이용한 다양한 시뮬레이션 고찰을 수행한다.

• Tribology and Lubricants
• /
• 제3권1호
• /
• pp.52-60
• /
• 1987

Many kinds of condition monitoring technique as the preventive maintenance technique have been studied, so this study has investigated the possibility of chbcking the trend in the fault diagnosis of ball bearing, one of the important elements of rotating machine, by applying the cepstral analysis method. And computer simulation is conducted in order to identify obviously the physical meaning of cepstral analysis. It is identified that cepstral analysis is effective method to distinguish between the basic and reflected wave by computer simulation, and we know that it is possible to apply the cepstral analysis to the arbitrary elements of rotating machine which are different in fundamental frequency. It is verified that cepstral analysis method is more effective than the other conventional method in bearing fault diganosis.

• 한국정밀공학회지
• /
• 제15권1호
• /
• pp.19-25
• /
• 1998

Remote fault diagnosis and maintenance system using general telecommunication network is necessary for an effective fault diagnosis and higher productivity of NC machine tools. In order to monitor machine tool condition and diagnose alarm states due to electrical and mechanical faults, a remote data communication system for monitoring of NC machine fault diagnosis and status is developed. The developed system consists of (1) remote communication module among NC's and host PC using PSTN. (2) 8 channels analog data sensing module, (3) digital I/O module for control or NC machine, (4) communication module between NC machine and remote data communication system via RS-232C, and (5) software man-machine interface. Diagnostic monitoring results generated through a successive type inference engine are displayed in user-friendly graphics. The validity and reliability of the developed system is verified to be a powerful commercial version on a vertical machining center through a series of experiments.

• 대한기계학회논문집
• /
• 제17권8호
• /
• pp.2061-2068
• /
• 1993

Condition monitoring technology is of great importance for the maintenance of complex machinery in view of its early monitoring of the abnormal condition and the protection against failure. Several methods have been used for the detection of failure of journal bearings, one of the main elements of mechanical system. The methods most frequently used are vibration and temperature monitoring, but these are unable to monitor the wear conditions exactly. In this study, an ultrasonic measument method, one of the non-destructive testing methods, was introduced as the monitoring technology. Furtermore a pattem recognition method was applied to analyze the ultrasonic signal. The monitoring system using the pattern recognition method is composed of digital signal processing units and uses Hamming net algorithm for the recognition of ultrasonic waves. From the journal bearing wear test, the occurrence of adhesive wear of the white metal in rubbing contact with the shaft was exactly detected by this system, and the wear status of the journal bearing was monitored by measuring the wear thickness.

• 한국구조물진단유지관리공학회 논문집
• /
• 제10권2호
• /
• pp.191-202
• /
• 2006

구조물을 설계할 때 사용하는 컴퓨터 프로그램들은 구조물에 작용하는 각각의 조건을 고려한 최적의 설계를 할 수 있도록 도움을 준다. 하지만 컴퓨터 프로그램은 단순화시키고 일반화시킨 조건들을 적용하기 때문에 그 결과들은 실제 구조물의 거동을 정확히 설명할 수 없다. 이러한 문제점들을 극복하기 위해서 도입된 것이 스마트 구조이고 스마트 시스템을 통해 구조물을 상시 계측함으로서 실제 구조물의 정확한 거동을 파악할 수 있다. 본 연구는 실험을 통해 기존의 구조설계방법에 의한 구조물의 거동과 실제 구조물의 거동을 비교하여 계측시스템의 타당성 검토와 함께 앞으로의 발전가능성을 알아보고자 한다.

• 한국추진공학회지
• /
• 제17권1호
• /
• pp.80-88
• /
• 2013

최근 개발되는 엔진 진단 시스템들은 현장에서 일하는 엔진 정비사들이 이들 시스템들의 복잡성, 비실용성, 공학적 이해부족으로 사용하기가 매우 어렵다. 따라서 실용성 있는 엔진 진단시스템이 요구된다. 본 연구는 작동중인 온라인 성능진단 자료와 기본엔진 성능모델에 의해 계산된 초기고장이 없는 엔진 성능자료와의 비교를 통한 소형엔진의 실용적 성능진단 시스템 개발에 관한 것이다. 또한 제안된 성능진단 시스템은 성능이 저하되거나 고장이 난 엔진으로 간주되는 작동 중 엔진과 고장이 없는 엔진으로 간주되는 기본 엔진 성능모델 사이의 구성품 성능특성을 비교함으로서 가스경로 구성품의 온라인 진단을 확인할 수 있다. 개발된 상태진단시스템은 실제 적용을 용이하게 하기위해 SIMULINK와 LabVIEW프로그램을 이용하여 사용자조건의 GUI형 프로그램으로 작성하였다.

• International Journal of Fluid Machinery and Systems
• /
• 제5권4호
• /
• pp.143-151
• /
• 2012

Predicting the future condition of machine and assessing the remaining useful life are the center of prognostics. This paper contributes a new prognostic method based on grey model and survival probability. The first step of the method is building a normal condition model then determining the error indicator. In the second step, the survival probability value is obtained based on the error indicator. Finally, grey model coupled with one-step-ahead forecasting technique are employed in the last step. This work has developed a modified grey model in order to improve the accuracy of prediction. For evaluating the proposed method, real trending data of low methane compressor acquired from condition monitoring routine were employed.

• 소음진동
• /
• 제22권4호
• /
• pp.28-32
• /
• 2012

Condition-based maintenance on wind turbines not only involves maintenance, but also encompasses servicing, inspection, measurement and evaluation of the condition of the unit. The current condition can be evaluated on the basis of machine-specific overall vibration values. Until now, overall vibration values had not been defined for wind turbines. In fact, ISO 10816-3 explicitly excludes wind power plants. The new VDI 3834 closes this gap shown in Sheet 1: Vibration values for wind turbines up to 3 MW. In addition to the new VDI 3834 is the ISO 10816-21 in preparation. The author of the article Dr. Edwin Becker is the nominated expert for Germany.