페트리네트의 구조화를 통한 스퀀스제어계의 모델링

정석권(Seok-Kwon Jeong),양주호(Joo-Ho Yang) 한국정밀공학회 1998 한국정밀공학회 학술발표대회 논문집 Vol.1998 No.5월

PI와 피드포워드 제어를 이용한 공작기계용 오일쿨러의 핫가스 바이패스 방식 정밀 온도 제어

정석권(Seok-Kwon Jeong),변종영(Jong-Yeong Byun),김상호(Sang-Ho Kim),윤정인(Jung-In Yoon) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.2

Recently, the performances of speed and accuracy are enhanced in machine tools. The high speed of the machine tools usually causes harmful thermal displacements on the objects. To reduce the thermal displacements, machine tools generally adopt oil coolers with precise temperature control function. This study aims at precise control of oil outlet temperature in the oil coolers with hot-gas bypass manner based on PI control logic. The control system was designed for obtaining steady state error within ±0.1℃ and maximum overshoot with 0.8% even though abrupt disturbances are added to the system. We showed that the PI gains could be easily decided by numerical simulations using practical transfer function which got experiments. Also, transient characteristics could be improved significantly by reflecting the inlet temperature of an evaporator to the output of a controller feedforwardly considering periodic abrupt disturbances. Through some experiments, excellent control performances were established by the suggested control.

페트리네트의 T-invariance를 이용한 시스템의 고장진단

정석권(SEOK-KWON JEONG),정영미(YOUNG-MI JUNG),유삼상(SAM-SANG YOU) 한국해양공학회 2001 韓國海洋工學會誌 Vol.15 No.4

This paper describes a fault diagnosis method by a T-invariance of Petri Net (PN). First, a complicated fault system with some failure is modeled into a PN graphic expressions. Next, the PN model is analyzed by using the backward chaining of T-invariance to find out causes of the faults. In this step, an inter-node search technique which is suggested in this paper is applied for reducing searching area in the fault system. Also, a novel idea to compose incidence matrices which have different dimension each other in PN model is proposed. As the new knowledges which is discovered newly about faults can be added easily to conventional systems, the diagnosis system will be very flexible. Finally, the proposed method is applied to the automobile fault diagnosis system to confirm the validity of the method.

페트리네트의 계층화를 통한 시퀀스제어계의 설계 (Ⅱ)

정석권(SEOK-KWON JEONG),정영미(YOUNG-MI JUNG),유삼상(SAM-SANG YOU) 한국해양공학회 2001 韓國海洋工學會誌 Vol.15 No.4

Petri nets have been introduced as a powerful analyzing and design tool for the discrete systems such as sequential control systems. However, one of the important problems in its applications is that the model can be analyzed hardly when we deal with large scale systems because of increase of the number of Petri net components. To overcome this problem, some methods for dividing or reducing of Petri net have been suggested. In this paper, an approach for hierarchical expression of Petri net based on Sequential Function Chart(SFC) and Bottom Up oriented Mehodology(BUM) is proposed Especially, some definitions and rules are defined in order to divide and compose sub Petri nets. A measuring tank system will be described as a typical kind of discrete systems and modeled by some sub Petri nets based on the SFC and BUM by the proposed method in this paper.

터보냉동기를 위한 실용적 모델링과 PI 제어기 설계

정석권(Seok-Kwon Jeong),한성준(Sung-Joon Han),정영미(Young-Mi Jung) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.4

This paper describes the PI controller design based on a practical transfer function model for centrifugal water chillers. The rotational speed of a compressor and the opening angle of an electronic expansion valve were simultaneously regulated as manipulated variables to maintain temperature reference and to ensure high efficiency of the chiller. The COP according to the change in each variable was investigated by performing some static experiments, and it was reflected in the PI controller design to accomplish the high efficiency control. Especially, the practical transfer function model of the chiller was built based on the dynamic experimental data considering the strong inherent non-linearity and complexity of the chiller system. The validity of the designed PI controller was proven by some experimental results using the test facility and the results were also compared to the conventional evaporating pressure control results.

상태공간 모델링에 의한 공작기계용 수냉각기의 최적제어기 설계

정석권(Seok-Kwon Jeong),김상호(Sang-Ho Kim) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.12

Typical temperature control methods of a cooler for machine tools are hot-gas bypass and compressor variable speed control. The hot-gas bypass system has been widely used to control the cooler temperature in many general industrial fields. On the contrary, the compressor variable speed control is focused on special fields such as aerospace and high precision machine tools which need high precision control. The variable speed control system usually has two control variables such as target temperature and superheat. In other words, the variable speed control system is basically multi-input multi-output(MIMO) system. In spite of MIMO system, the proportional integral derivative(PID) feedback control methodology that based on single-input single-output (SISO) system is generally used for designing the variable speed control system. Therefore, it is inevitable to describe transfer functions for dynamic behaviors of every controlled variables and decide the PID gains with tremendous iteration process. Moreover, the designed PID gains do not provide optimum system performances. To solve these problems, high performance controller design method based on a state space model is suggested in this paper. An optimum controller is designed to minimize both control errors and energy inputs. This method was more simple to describe dynamic behaviors and easier to design the cooler controller which is MIMO system.

외란을 고려한 냉동시스템의 최적 PI 제어기 설계

정석권(Seok-Kwon Jeong),홍기학(Ki-Hak Hong) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.2

The proportional plus integral(PI) feedback control manner has been used in many general industrial fields such as refrigeration system because of its simple design process and favorable control performance. This paper deals with optimized PI controller design of the refrigeration system based on evaluation functions such as integrated absolute error(IAE). The suggested optimal PI gains can be easily calculated by a simple program and the optimal controllability satisfying the evaluation function can be assured. Furthermore, at the initial step of controller design, the suggested optimal gain is able to reflect some noise disturbances caused by an inverter which drives variable speed compressors. The validity of the suggested optimal gain is investigated by some simulations and experiments to verify its efficiency. From the results of comparing control performance between the optimal PI controller based on the evaluation function and the PI controller designed by the Matlab tuner which was known as the most popular gain tuner, the optimal PI controller showed more desirable control performance especially in transient responses.

페트리네트의 계층화를 통한 시퀀스제어계의 설계 (Ⅰ)

정석권(Seok-Kwon Jeong),양주호(Joo-Ho Yang) 한국해양공학회 1999 韓國海洋工學會誌 Vol.13 No.3(Ⅱ)

Modeling a discrete event system such as a sequential control system is difficult compared with a continuous system. Petri nets have been introduced as an analyzing and design tool for the discrete systems. One of the problems in its applications is that the model can not be analyzed easily in the case of large scale or complicated systems because of increase of the number of components of the system. To overcome this problem, some methods for dividing or reducing Petri nets have been suggested. In this paper, an approach for a hierarchical expression of Petri nets based on Sequential Function Chart(SFC) is proposed. A measuring tank system will be described as a typical kind of discrete systems. The system is modeled by sub Petri nets based on SFC in order to analyze and visualize efficiently about the dynamic behaviors of the system. Some numerical simulations using state equations are performed to prove the validity of the proposed method.

페트리네트에 의한 탈팬장치의 시퀀스제어계 모델링

정석권(Seok-Kwon Jeong) 한국해양공학회 1998 韓國海洋工學會誌 Vol.12 No.4

Petri net has been used as analytical tool for discrete event-driven systems such as sequential control systems owing to the capability of representation and analysis of dynamic behaviors in the systems. However, one of the problems in its applications is that the model requires a lot of computer memories and long computation times in accordance with increase the number of components of the system. Also, the Petri net model of a large scale system can not be understand intuitively due to the complexity of graphical description. To overcome these problems, some methods have been suggested toward dividing or reducing of Petri nets.<br/> In this paper, an approach for dividing of Petri nets based on Sequential Function Chart is proposed. A sequential control system for a device of automatic removing pan will be described as a typical kind of discrete system. Each component of input and output of the system will be modeled by divided sub Petri nets in order to analyze and visualize easily about the dynamic behaviors of the system.

An Identification Method of Secondary Resistance for Quick Torque Control in Induction Motors

Seok-Kwon Jeong(정석권),Jung-Hoan Byun(변정환) 한국해양공학회 1997 韓國海洋工學會誌 Vol.11 No.4

최근 유도전동기를 이용한 가변속 구동시스템의 수요가 자동화 및 에너지의 효율적 이용 측면에서 육상 산업체는 문론, 선박 및 해양플랜트에도 확산되고 있다. 유도전동기의 토크 고속제어법은 가변속 구동시스템의 고성능화를 위한 필수과제로서, 제어법 적용시 2차저항의 동정문제가 대단히 중요하다.<br/> 본 논문에서는 유도전동기의 토크 고속 응답제어계에 있어서 고정도의 토크응답을 실현하기 위한 2차저항 동정법을 제한한다. 제안된 방법은 모터의 회로방정식으로부터 유도되며, 모터의 인가전압과 1차전류 정보로부터 간단히 구현된다. 제안된 방안의 타당성을 검증하기 위하여 펄스폭변조방식의 전압형 인버터를 상정한 수치 시뮬레이션을 수행하며 그 결과를 통하여 제안방식의 유용성을 입증한다.