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정밀레벨측정을 위한 FMCW 타입의 레이더 레벨 트랜스미터 구현
지석준(Suk-Joon Ji),이준탁(Joon-Tark Lee) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.3
In this paper, Zoom FFT is applied to the method of distance measurement using beat frequency in order to improve the precision of distance measurement for FMCW Radar Level Transmitter. Distance precision is improved from 146.5mm to 5mm using the advantage of Zoom FFT which can raise the frequency precision without changing the sampling frequency or FFT point number to be fixed in the beginning of designing signal processing. For verifying the effectiveness of this Zoom FFT to FMCW Radar Level Transmitter, test bench is made to measure the distance for every 1mm between 700mm and 2000mm and measurement error can be checked in the range of ±5mm.
상관분석법을 이용한 FMCW 타입 레이더 레벨 트랜스미터의 정밀 거리 측정에 관한 연구
지석준(Suk-Joon Ji),이준탁(John-Tark Lee) 대한전기학회 2012 전기학회논문지 Vol.61 No.7
In this paper, FMCW type radar level transmitter using correlation analysis method is implemented for precise distance measurement of cargo tank. FMCW type radar level transmitter is the device for distance measurement which calculates the distance by analyzing the beat frequency, that is, the frequency difference between Tx and RX signal from radar antenna using Fast Fourier Transform(FFT), but compensated algorithm like Zoom FFT is needed for the improvement of the frequency precision because the frequency precision of FFT is limited depending on sampling frequency and the number of sampling data. In case of Zoom FFT, the number of sampling data and noisy signal are the main factor influencing the measurement accuracy of Zoom FFT like FFT. Therefore, in order to overcome the limited environment and achieve the precise measurement, correlation coefficient is used for the distance measurement and the errors of measurement are verified to be in the range of ±1㎜.
선박 Cargo Tank의 수위측정을 위한 FMCW Radar type의 레벨트랜스미터
지석준(Suk-Joon Ji),이준탁(Joon-Tark Lee) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
본 논문에서는 선박 Cargo Tank의 액위 측정을 위한 FMCW (Frequency Modulated Continuous Wave) Radar type의 레벨트랜스미터에 관하여 연구를 소개하였다. 일반적으로 FMCW Radar type의 레벨트랜스미터는 주파수를 송수신하는 Front-end부와 송수신신호에서 추출한 차주파수(beat Frequency)의 처리를 위한 아날로그처리부, 측정된 차주파수를 이용하여 Tank의 액위를 계산하는 디지털처리부로 구성된다. 개발 중인 FMCW Radar type 레벨트랜스미터는 실제 적용될 선박의 Cargo Tank를 가상화하여 제작한 실험용 Tank에서 실험을 진행하였으며, 약 ±7㎜ 이내의 측정오차가 발생하였다. 향후 Cargo Tank 내의 장애물, Echo Cancel에 대한 신호처리와 알고리듬 연구, VCO 선형성 개선을 통해 정확도 ±3㎜ 이내의 FMCW Radar type 레벨트랜스미터를 개발하여 상용화하는 것이 목표이다.
Hybrid GA-PID WAVENET 제어기를 이용한 모형 헬리콥터 시스템의 자세 제어
박두환,지석준,이준탁 대한전기학회 2004 전기학회논문지 D Vol.53 No.6(D)
The Helicopter Simulator System is non-linear and complex. Futhermore, because of absence of its accurate mathematical model, it is difficult to control accurately its attitudes such as elevation angle and azimuth one. Therefore, we proposed a Hybrid GA-PID WAVENET(Genetic Algorithm Proportional Integral Derivative Wavelet Neural Network)control technique to control efficiently these angles. The proposed Hybrid GA-PID WAVENET is made through the following process. First, the WAVENET fundamental functions are defined. And their dilation and translation values are adjusted by GA to construct the optimal WAVENET controller. Secondly, the proportional, integral, and derivative gain coefficients of PID controller are tuned optimally. Finally, WAVENET controller which has a good transient characteristic and GA-PID controller which has a good steady state characteristic is adequately combined in hybrid type. Through the computer simulations, it is proved that the Hybrid GA-PID WAVENET control technique has a more excellent dynamic response than PID control technique and GA-PID one.
Development of the Micro-controller Based Low Cost Gas Sampling System for Vessels
Choi, Woo-Jin,Ji, Seok-Jun,Lee, Joon-Tark 東亞大學校 海洋資源硏究所 2003 硏究論文集 Vol.15 No.-
We have developed the micro-controller based low cost gas sampling system which has micro-controller based two pumps and forty eight channels for vessels or crude oil tankers. Our low cost gas sampling system offers compact and accurate detection solutions, high reliability, and the flexibility to adapt to specific user requirements. At same time, an infrared hydrocarbon gas detector is synonymous with safety even in flammable environments, providing early alarm notice of potentially dangerous gas levels. Simplicity with flexibility has been the focus of this design. Installation is easy and protection assured from the smallest vessels to the large crude oil tankers. Futhermore, this system offers the important informations of each tank such as gas concentration, alarm, flow rate, system default and leakage on a graphic LCD window. Therefore, because of its advantages of low cost, high performances, simplicity of control and fluent interfacing with the other equipments, it is possible to design an integrated control system with analysis functions and alarm units.
동기전동기의 안정된 운전을 위한 퍼지 부하각 제어시스템에 관한 연구
이관태,지석준,이준탁 한국지능시스템학회 2007 한국지능시스템학회 학술발표 논문집 Vol.17 No.1
동기기가 전동기의 모드로 운전하고 있을 때, 동기속도로 안정된 운전을 하는 중 순간적으로 과부하가 인가되게 되면 이로 인해 동기 이탈 현상이 발생한다. 동기속도로 운전 중인 동기전동기가 동기이탈을 하게 되면 계통의 역률, 안정도 등에 치명적인 악영향을 미치게 되어 여러 가지 손실을 가져오게 된다. 동기전동기가 안정된 운전을 할 수 있도록 하기 위한 한 가지 요인인 부하각을 제어하게 되면 앞에서 말한 위험한 상황을 예방 할 수가 있다. 본 논문에서는 동기전동기의 부하각을 마이크로프로세서에 의해 퍼지 부하각 제어 기법을 적용하여 동기전동기의 안정된 운전을 행하고자 하였다.
RVEGA를 이용한 온도 제어 시스템의 최적 퍼지제어기 설계에 관한 연구
김정수,박두환,지석준,이준탁 동아대학교 생산기술연구소 2001 生産技術硏究所硏究論文集 Vol.6 No.2
In general, the thermal control system has nonlinearity and the time delay, futhermore, it is difficult to design the free size controller, because the external environmental disturbances, such as rapid temperature change. Many researchers in this field are preferring to adapt the fuzzy logic controls, but it is noted that the actuator identification of M.F.'s used in FLC is very difficult. Therefore in this paper, an implementation technique of thermal control system using RVEGA based optimal fuzzy control was proposed. It's superiority and exaction in controller design processes hardware in implementation were proved through a series of simulations and experimentations.