• Journal of Biosystems Engineering
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• 제16권2호
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• pp.148-158
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• 1991

This study was undertaken to develop the feed rate control system for the head feed thresher by making use of the microprocessor and to evaluate the response of the system to a various threshing conditions. It was verified the performance of the control system through experiments. Control conditions were determined based on the simulation results of control system. The control system set at RH=500rpm, RL=480rpm for the bundle feed was considered optimum to give a high threshing capability and still to stabilize the feeding seed regardless of the bundle size. The control system for the continuous spread feed set at the range of LH=15mm, and LL=12mm gave a high control performance for the feeding mass of 1.1Kg/m and lower tested. In addition, the feed rate proportionality constant should be set lower than one in order to keep the rotational speed of threshing cylinder within the range of 500~520rpm.

• Journal of Biosystems Engineering
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• 제16권2호
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• pp.124-132
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• 1991

This study was carried out to obtain the information needed in the development of forward speed control system and the improvement of combine performance. The effects of variety, grain moisture content and forward speed on the combine load characteristics were investigated through experiments. The results of this study are summarized as follows. 1. A data acquisition system was developed to measure the engine speed and the torques and speeds of the threshing cylinder, dean-grain auger and tailings-return auger. The system consisted of transducers, signal conditioner, interface board and microcomputer. The system accuracy is better than ${\pm}2.3%$ full scale. 2. Linear regression equations were obtained for the torque, speed and power requirement of threshing cylinder for different paddy varieties, grain moisture contents and feed rates. 3. The maximum value of relative frequency for threshing cylinder torque decreased as the increase in feed rate and moisture content. The range of torque fluctuation was 1.2~3.7 and 1.2~1.9 times the average and maximum torque, respectively. The maximum value of power spectrum density (PSD) appeared to be about 11 Hz regardless of paddy variety, grain moisture content and feed rate. 4. The speed of tailings return thrower decreased rapidly at below 900rpm, and it fell to near zero about 3 seconds after that time. When the travelling of combine harvester was stopped immediately after sensing the overload, it took about 7 seconds for a full recovery of the no-load speed of tailings return thrower.

• Journal of Biosystems Engineering
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• 제15권2호
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• pp.110-122
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• 1990

This study was undertaken to develop the feed rate control system for the head feed thresher by making use of the microprocessor and to evaluate the response of the system to a various threshing conditions. The control unit was composed of one-board microcomputer. The speed of the wet-paddy feeding chain was controlled by dc moter with PI controller. It was used the adaptive control method to maintain the constant feed rate regardless of the fed rice varieties. The sliding type potentiometer was used as the feed rate sensor, which was attached on the sheaf-holding apparatus. The mathematical models of the system components were derived and computer simulation was developed for investigating the parameters affecting on control performance and for estimating the response of the system. A one-board microcomputer-based feed rate control system developed in this study was properly functioned and assessed as adequate for the feed rate control system of the head feed thresher. Based on the simulation for the bundle feed, it was anticipated that the lower setting value of the cylinder speed(RL) is to be set higher than the limiting operational speed. In addition, the higher setting value of the cylinder speed(RH) is to be set lower than the limiting cylinder speed for threshing. The computer simulation for the continuous spread feed showed that the lower the setting value of straw layer thickness(LL) was set, the shorter the correction time. However, if too low LL may be established, the feed rate could not reach to its desired rate.

• 한국작물학회지
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• 제31권2호
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• pp.150-155
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• 1986

콩을 탈곡기로 탈곡할 때 종실손상율이 낮으면서 발아율이 높은 종실의 수분함량과 탈곡기의 적정 급동속도를 구명하여 기웅탈곡시에 필요한 기초자료로 활용코자 시험을 실행하여 얻어진 결과를 요약하면 다음과 같다. 1. 성숙시 식물체 각 부위별 수분함량은 대입종인 황금콩의 경우 줄기, 종실, 콩깍지 순으로 소입종인 단엽콩은 줄기, 콩깍지, 종실 순으로 많았다. 2. 황금콩과 단엽콩의 성숙후 식물체 부위별 수분함량과 수분함량 감소정도는 줄기 및 종실에서는 비슷하였으나 콩깍지는 소입종인 단엽콩이 성숙후 7 일까지는 황금콩보다 높았고 그 후에는 차이가 없었다. 3. 성숙후 7 일의 일중의 줄기, 종실, 콩깍지의 수분함량 변이는 시간이 경과함에 따라 수분함량이 감소하는 경향이며 성숙후 14일에는 오전 11시까지 꼬투리의 수분함량이 종실의 수분함량보다 높았으나 그 이후에는 종실의 수분함량이 더 높았다. 4. 콩 탈곡시 탈곡기의 급동속도가 빨라지거나 종실수분함량이 많아질수록 종실보상율은 증가는 경향이며 대입종인 황금콩이 소입종인 단엽콩보다 종실 보상입율이 높았다. 5. 보상입율과 발아율을 고려할 때 탈곡기의 적정급동속도는 11 m/sec.가 적당한 것 같았다. 6. 탈곡에 알맞는 종실의 수분함량은 수량, 보상입율, 발아율, 작업속도 및 건조작업 등을 고려할 때 종실의 수분함양이 15∼20%가 적당한 것 같았다.

• Journal of Biosystems Engineering
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• 제13권3호
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• pp.20-31
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• 1988

This study was undertaken to investigate the load characteristics of the head-feed thresher, which may be affected by various factors such as physical properties of grain, thresher design parameters and its operational condition. The study was conducted at an initial step toward developing an automatic feed-rate control system of the head-feed thresher. A microcomputer-based data acquisition system for the load-speed characteristic of the thresher-shaft and the rail-deflection of the feeding device in accordance with a varied feeding thickness was developed. The sensors being developed and used for sensing the torque and speed of the cylinder and the power-input-shaft and the feeding thickness showed a high accuracy. A microcomputer-based data acquisition system developed in this study was assessed as adequate for a rapid acquisition and analysis of data. The effect of the feed-rate on the torque and speed of the thresher shaft, when fed intermittently by bundles, affected not by the rice varieties but by the dryness of threshing material tested. When fed by the continuous constant thickness, the torque and speed of the cylinder due to the increase of the feed-rate or feeding thickness were given by the relation by the second order parabola.