• Journal of the Korea Society of Computer and Information
• /
• v.25 no.4
• /
• pp.19-27
• /
• 2020

In this paper, we propose a machine learning method for diagnosing the failure of a gas pressure regulator. Originally, when implementing a machine learning model for detecting abnormal operation of a facility, it is common to install sensors to collect data. However, failure of a gas pressure regulator can lead to fatal safety problems, so that installing an additional sensor on a gas pressure regulator is not simple. In this paper, we propose various machine learning approach for diagnosing the abnormal operation of a gas pressure regulator with only the flow rate and gas pressure data collected from a gas pressure regulator itself. Since the fault data of a gas pressure regulator is not enough, the model is trained in all classes by applying the over-sampling method. The classification model was implemented using Gradient boosting, 1D Convolutional Neural Networks, and LSTM algorithm, and gradient boosting model showed the best performance among classification models with 99.975% accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.11a
• /
• pp.377-378
• /
• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.775-776
• /
• 2009

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.86-89
• /
• 1986

This paper presents a design methodology for a PID regulator. The parameters of the PID regulator are determined through equivalent structure to the closed-loop system whose feedback gain assigns prescribed eigenvalues of the closed-loop system and minimizes a given performance index.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.6
• /
• pp.573-576
• /
• 2009

We present a passive flow-rate regulator, capable to compensate inlet pressure variation and to maintain a constant flow-rate for precise liquid control. Deflection of the parallel membrane valves in the passive flowrate regulator adjusts fluidic resistance according to inlet fluid pressure without any external energy. Compared to previous passive flow-rate regulators, the present device achieves precision flow regulation functions at the lower threshold compensation pressure of 20kPa with the simpler structure. In the experimental study, the fabricated device achieves the constant flow-rate of $6.09{\pm}0.32{\mu}l/s$ over the inlet pressure range of $20{\sim}50$ kPa. The present flow-rate regulator having simple structure and lower compensation pressure level demonstrates potentials for use in integrated micropump systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10b
• /
• pp.841-846
• /
• 1990

In this study, a design method to obtain a robust suboptimal regulator for linear multivariable system is presented. This new design method is based on the optimal regulator design method using eigen-structure assignment and it uses additional cost function which represent robustness of the closed loop system. When we design the regulator using pole assignment method for linear multivariable system we have extra degree-of-freedom after assigning desired eigenvalues of the closed loop system in determining the feedback gain. So we assign additional robust suboptimal regulator. In this study we also feedback the system output for more practical applications.

• Proceedings of the Korean Reliability Society Conference
• /
• 2002.06a
• /
• pp.123-129
• /
• 2002

본 논문에서는 Regulator IC의 불량원인 규명을 통해 반도체 고장분석 방법 및 개선사례를 소개하고자 한다. 고장분석에 사용된 반도체 Package는 8Pin MSOP(Mini Small Outline Package)로, 시장 불량품을 분석한 결과 Regulator IC의 Stitch Bond에 Heel Crack이 발생하여 불안정한 출력을 발생시킴을 알 수 있었다. Stitch Bond Heel Crack의 원인은 Lead Frame부의 박리(Delamination)에 의해 열이나 진동 등의 외부 Stress가 직접 Stitch Bond에 가해져 Crack이 발생된 것으로, Reflow 재현시험을 통해 확인 할 수 있었다. 박리 발생에 의한 Stitch Bond Heel Crack 방지 대책으로 첫째, Bonding Type을 Stitch Bond 에서 Ball Bond로 변경하여 강도를 개선하고 둘째, PCB Layout 변경을 통해 외력이 직접 Regulator IC에 가해지지 않도록 하였다. 개선 결과 현재까지 시장에서 동일 불량은 발생하지 않았다.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1020-1021
• /
• 2015

본 논문에서는 상용전압 AC 220V를 인가전압으로 사용하여 PMIC(Power Management IC)의 구동에 적합한 전압을 인가해주는 Pre-Regulator를 설계하였다. 설계된 Pre-Regulator는 상용전압을 사용하기 때문에 Device의 내압이 700V인 Magnachip $0.35{\mu}m$ BCD 공정을 이용하여 설계되었으며, 회로의 구성은 저전압 입력 보호 기능 및 JFET의 구동 제어를 위한 Under Voltage Lock Out(UVLO)회로, 전압조정기(Regulator)의 기준전압을 생성해주는 밴드갭 기준전압 발생(Bandgap Reference)회로, LDO(Low Drop Out)회로로 구성되어있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.11
• /
• pp.69-75
• /
• 2009

In this paper, a self-tuning regulator for a speed control of a permanent magnet type stepping motor is proposed. The self-tuning theory provides a nonlinear modeling of a stepping motor drive system and can provide the controller with information regarding the reference variation and parameter variation of the stepping motor through the on-line estimation. The proposed self-tuning regulator organize the positive feedback loop and IP(Integral-Proportional) type. Therefore, the proposed self-tuning regulator has a robust control capabilities during dynamic operation. The availability of the proposed controller is verified through experimental results.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.2
• /
• pp.129-132
• /
• 2011

This paper presents small hydrogen regulator for the mobile fuel cell. Mobile fuel cell is generally classified into open-end type and dead-end type. In the open-end type, flow rate of hydrogen is constantly controlled, while pressure of hydrogen is constantly maintained in the dead-end type. Considering the efficiency and stability of the fuel usage, dead-end type is more suitable with mobile fuel cell. Mobile fuel cell operated by dead-end mode requires hydrogen regulator which controls the hydrogen pressure from 0.1bar to 0.5bar within 3% error. In this paper, small hydrogen regulator (volume of 2.6cc) was fabricated by stainless steel. Regulation characteristics was experimentally evaluated.