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하주식,최경삼,김승호,Ha, Joo-Shik,Choi, Kyung-Sam,Kim, Seung-Ho 한국마린엔지니어링학회 1979 한국마린엔지니어링학회지 Vol.3 No.1
Recently the adaptive control system, which keeps the control system always optimal by adjusting the control parameters automatically according to the variations of the plant parameters, have become very important in the field of control engineering. The adaptive control systems are usally composed of the plant identification, the decision of the optimal control parameters, and the adjustment of the control parameters. This paper deals with a method of the adaptive control system when PI or PID controller is used in the feed back control system. Its controlled object (the plant) is assumed to be described by the transfer function of $\frac{ke^{-LS}}{1+TS}$ where k, T and L are steady state gain, time constant and pure dead time respectively, and their values are variable in accordance with the change of environmental circumstance. It has been known that a pseudo-random binary signal is quite effective for the measurement of an impulse response of a plant. In adaptive control systems, however, the impulse response itself is not appropriate to determine the control parameters. In this paper, the authors propose a method to estimate directly the parameters of the plant k, T and L by means of the correlation technique using 3 level M-sequence signal as a test signal. The authors also propose a method to determine the optimal parameters of the PI or PID controller in the sense of minimizing the square integral of the control error in the feed back control system, and the values of the optimal parameters are computed numerically for various values of T and L, and the results are examined and compared with those of the conventional methods. Finally the above-mentioned two methods are combined and an algorithm to struct an adaptive control system is suggested. The experiments for the indicial responses by means of both the model of the temperature control system using SCR actuater and the analog simulations have shown good results as expected, and the effectiveness of the proposed method is verified. The M-sequence generator and the time delay circuit, which are manufactured for the experiments, are operated in quite a good condition.
지연요소를 수반하는 일차계통의 패러미터 추정에 관한 연구
하주식(Joo Shik Ha) 대한전기학회 1969 전기의 세계 Vol.18 No.1
A lot of recent researches have shown that a Pseudo Random Binary Signal is a quite effective test signal to measure the impulse response of a plant. Generally speaking, however, such a response itself is not satisfactory to determine the appropriate control parameters or control inputs. Here, the author intends to estimate the unknown parameters of the First Order Plant with Dead Time by means of correlation method using M-sequence signal. The time constant T and the dead time L of the plant are eatimated with one tracking loop by automatically adjusting delay time .tau. of M-sequence signal according to variations of T and L. In this paper, a three level M-sequence signal is used as a test signal in order to avoid troublesome operations to calculate partial derivatives of a given performance index with respect to the parameters which are usually required in the Model Method. Several experiments with analogue computer using low pass filters as averaging circuits showed good results as expected.
박재식(Jae-Shik Park),소명옥(Myong-Ok So),오세준(Se-June Oh),유희한(Hee-Han Yoo),박진길(Jin-Gil Park),하주식(Joo-Shik Ha) 한국마린엔지니어링학회 2003 한국마린엔지니어링학회 학술대회 논문집 Vol.2003 No.-
Photovoltaic power generation systems are expected to be widely used becase of their cleanness in the environment. But one of their disadvantages is the unexprected fluctuation of photovoltaic power generated by the weather conditions.<br/> This paper proposes to predict the output fluctuation of photovoltaic power by analyzing clouds through the image processing technique. First, the velocity of the cloud in the image is calculated by the comparison between two sequential images of the cloud, and then, the weather conditions are forecasted by examining the color values of the image along the direction of the cloud movement. Experimental results, the weather forecast 60, 90 and 120 seconds ahead and the estimation of the time required for the solar radiation to fluctuate on a large scale, show the possibility of the prediction of the output fluctuation of photovoltaic power generation system.<br/>
김창세(Chang-Se Kim),하윤수(Yun-Su Ha),하주식(Joo-Shik Ha) 한국해양대학교 해사산업연구소 1998 海事産業硏究所論文集 Vol.7 No.-
DC servo motors are widely used in many industrial fields as actuator of robot and driving power motors of electrical vehicle. Usually in the speed control systems of DC servo motors, speed sensors are required and this fact results in the increased price and operating cost and the limitted application of the motors. In this paper, a new speed control method for DC servo motor is proposed. In the scheme, the rotational speed is estimated by the measurement values of the armature voltage and current, instead of measurement by sensor. This paper also report on the results of experiments to prove the validity of the proposed method.