• 유공압시스템학회논문집
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• 제3권1호
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• pp.7-14
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• 2006

In this paper, an in-process diagnosis method for performance of position control servo system was studied, which was based upon null bias, slew-rate ratio and delay time measurement. Slew-rate ratio and delay time were analyzed by theoretical analysis, computer simulation and experiment. As a result of these analysis, when spool of servovalve was weared, slew-rate ratio was decreased and delay time was increased.

• 유공압시스템학회논문집
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• 제1권2호
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• pp.1-7
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• 2004

In-process diagnosis is essential to achieve predictive maintenance in industrial plants. An in- process diagnosis method was proposed for hydraulic servo systems, which was based upon leakage flow measurement. Leakage due to servovalve wear was analysed and modeled mathematically far computer simulation work. The key idea of diagnosis algorithm is that when monitoring signals, such as servovalve input and load displacement are in steady states, the return-line flow of hydraulic servo systems can be regarded as null-leakage of servovalve. Virtual experiments were performed to ensure effectiveness of the proposed diagnosis method.

• 유공압시스템학회논문집
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• 제6권2호
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• pp.22-30
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• 2009

An in-process method of diagnosing the spool wear of hydraulic servovalves was explored. The diagnostic method discussed in this paper is for force-control hydraulic servo systems. The key principle used is that pressure sensitivity of a servovalve drops as the valve spool wears out so that it is possible to determine the spool condition by monitoring pressure sensitivity. A diagnostic algorithm was developed and evaluated through numerical simulation and experiments. Two major steps of diagnosis are the evaluation of null bias of the servovalve and the approximation of pressure sensitivity, both of which could be successfully done during normal operation of a servo system. The difference between a new servovalve and a worn valve could be clearly detected in-process, and the diagnostic test was found to be repeatable.

• 기술혁신연구
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• 제28권4호
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• pp.1-26
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• 2020

전 세계적인 코로나19의 확산으로 인해, 진단시약 등과 같은 감염병 의료 및 의료기기 신제품이 비약적으로 개발·출시되고 있으며, 이의 빠른 수급을 위해 각 국가들은 수입규제를 완화하거나 신속한 인·허가를 위한 정책을 펼치고 있다(NIDS, 2020). 반면, 신종 감염병과 관련 없는 신개발 의료기기의 경우 오히려 시험검사 등 지연 및 취소되는 사례가 발생하고 있는 등 여전히 엄격한 인·허가규제를 통해 시장에 진출하고 있다. 이에 본 연구는 의료기기신제품이 시장에 진출하면서 마주하게 되는 정부소관법률에 특화하여 규제강도 영향요인을 도출하고 규제강도를 분석하여 규제대응 프레임워크를 제안하였다. 연구방법은 문헌연구, Failure Mode and Effects Analysis(FMEA)기법 적용, 전문가인터뷰(1차):아이디어수집, 전문가인터뷰(2차) : 타당성검증의 방법으로 진행하였으며, FMEA기법의 적용프로세스를 통해 우선 규제단계별 영향요인의 발생영향도와 규제사무 유형별 부담영향도를 곱하여 규제요인의 중요도를 구하고, 규제영향 심각도를 곱하는 방식으로 규제강도 정량화방법을 제시하였다. 시사점은 최근 해외 주요 국가들 및 우리나라 정부가 코로나19에 따른 신개발의료기기의 신속한 인·허가를 위한 특별규제정책 및 완화정책을 펼치며 적극적으로 대응하고 있는 시점에 본 연구에서 제안된 프레임워크를 통해 향후 기존 의료기기 신제품의 인·허가 정책 규제프로세스에도 보다 적극적이며 선제적인 대응이 될 수 있도록 규제의 개선방향과 규제대응 방안이 이루어지길 기대한다.