• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.351-358
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• 2000

This study was conducted to develop a speed control system of a DC motor which drove a barley seeder mounted on a combine harvester. Barley seeder mounted on a combine has been known to reduce labor and cost of barley cultivation. However, development of the seeder has been unsuccessful because the combine, a dedicated rice and barley harvester has not enough space and proper power take-off for barley seeder. To develop a barley seeder, small powered motor speed controller was required. A proximity sensor for detecting working speed of the combine and a programmable one board microprocessor was used to develope a control system. Motor parameters and motor constant, relationship between seeding rate, motor speed, groove volumes of a tested roller, torque were measured. The proximity sensor sent a frequency signal to the microprocessor. In laboratory experiments, the excitation voltage of the motor was shown not to be proportional to the size of pulse width (duty ratio). A table transforming frequency signal, that represented for working speed to proper pulse width was developed from seeding rate experiments. However, seeding rate at low frequency signal was not proportional to the working speed. Seeding rate control proportional to the frequency signal was achieved by shifting of the frequency signal.

• Journal of Biosystems Engineering
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• v.20 no.1
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• pp.36-46
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• 1995

The number of possible working days is one of the major factors for estimating the coverage area of a combine harvester. The percentages of possible working days at 24 locations were presented by analyzing the amount of rainfall during the working periods of rice harvesting from the end of September to the end of October for past 20 years. The percentages of possible working days ranged from 75% to 85% in most cases.

• Journal of Biosystems Engineering
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• v.19 no.3
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• pp.175-184
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• 1994

This study was conducted to investigate experimentally the basic characteristics of the torque of the cutterbar driving shaft as the double-knife was used instead of the conventional standard single-knife type. A new design for inclined setting of the cutterbar relative to the direction perpendicular to combine harvester movement was investigated to test a possible reduction of concentrated load caused by the simultaneous cutting of many rows. It was evaluated that the maximum torque and mean total power of the driving shaft due to the cutting resistance of the rice straw were largely depended upon the rotational shaft-speed and straw feeding rate, but were resepectively 1.1~2.3 and 1.15~1.34 times higher compared to those while idling. It was also proved that the inclined setting of the cutterbar could save a considerable amount of energy required for its driving shaft.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.30-37
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• 1999

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1998.12a
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• pp.56-61
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• 1998

• Journal of Biosystems Engineering
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• v.20 no.1
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• pp.3-12
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• 1995

This study was conducted to investigate the cutting mechanism of the reciprocating knife of combine harvester. The cutting operation of reciprocating knife was demonstrated through the cutting pattern diagram which was drawn by computer graphics. Various kinds and dimensions of standard-type reciprocating knives were analyzed by the developed program. The results are summarized as follows : (1) For the 50mm standard reciprocating knife, the bunching area and the maximum stalk-deflection were decreased rapidly according to the increase of cutting velocity ratio by 1.0 and decreased very slowly over this ratio. But, the secondary cut was occurred at ratio of 1.0 and increased rapidly over this ratio. (2) The 76mm standard knife showed better cutting mechanism than the 50mm, in two respects : the larger cutting area per one stroke and the lower revolutional speed of crank shaft for the same cutting velocity. (3) In respect to the bunching area and the secondary cutting length, the adequate height of 50mm standard reciprocating knife was 45~50mm. (4) In order to maintain the proper cutting mechanism, the adequate cutting velocity at forward speed of 0.5㎧ to 1.2m/s was from 0.4m/s to 1.2m/s for the standard knife.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.704-713
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• 1993

A principle for the determination of reel stagger, based on reel kinematics and crop stem deflection , is proposed. Equation derived theoretically and information obtained empirically are combined to obtain an algorithm for the determination of reel stagger. The algorithm has yet to be evaluated on actual combine harvesters in the harvesting mode.

• Journal of Biosystems Engineering
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• v.19 no.1
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• pp.22-32
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• 1994

The combine harvester is considered as an important but complicated and costly machine. The appropriate size of combine has to be developed to use efficiently in Korea. But the combine is such a complicated machine that a complete design model to develop a new type is impossible without understanding the relationship between each factor. The combine capacity is generally limited by the cleaning shoe performance. So a design model for a cleaning shoe has to be developed first for the complete combine design. The objective of this research was to develop a cleaning model of head-feeding combine to predict grain separation from chaff and broken straw on a sieve. A developed physically based model can explain the situation which can happen during separation process. A test apparatus based on the field going machine was developed. The test materials were paddy rice and barley. The data obtained were analyzed by the hand and the video camera. The developed model was verified as an adequate model through the test with $R^2$ of 0.934 and 0.837. The model can be used to evaluate design and operation alternatives of combine and also applied to the automatic control of separation unit of combine with a loss monitering sensors.

• Journal of Biosystems Engineering
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• v.19 no.3
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• pp.163-174
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• 1994

This study was conducted to investigate the dynamic motion of knife drive system of combine harvester. A computer program was developed to simulate the dynamic motion of the knife drive linkage and its algorithm was evaluated through experiments. The results are summarized as follows : 1. The theorectical horizontal (the direction of knife's reciprocating motion) reaction forces at the supporting point of rocker arm and crank arm were changed in the similar sinusoidal trends with the measured reaction forces. 2. The maximum values of shaking moment and reaction force per one revolution of crank arm followed polynomial trends as the rotational speed of crank shaft increased. The unbalanced force acting on the driving system increased at high speed. Therefore, the rotational speed of crank shaft should be maintained in proper range at increased forward speed to decrease vibration of the knife drive system. 3. The added mass to the crank arm increased the dynamic unbalanced force at the supporting point of rocker arm. It counterbalanced the reaction force at the supporting point of crank arm.

• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.142-157
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• 2001

This study was conducted to get the basic information for promoting farm machinery productivity by surveying the regular maintenance and repair status of major farm machinery such as power tiller, farm tractor, rice transplanter and combine harvester. The survey was carried out through 9 provinces including Cheju province by direct visiting farmers with prepared questionnaire. The results of this study can be summarized as follows : 1. The average farming carrier of the surveyed farmers was 25.3 years, and 21-30 years of farming carrier showed the highest portion as 40.7%. The average carrier of using farm machinery was 9.4 years, and that was 14.9 years for power tiller, 8.3 years for farm tractor, 9.0 years for rice transplanter, 7.9 years for combine harvester, 7.5 years for mini tiller, 9.7 years for power sprayer, and 8.2 years for binder etc. 2. The regular maintenance for farm machinery was conducted mainly at repair shop (49.5%) or dealer agency (12.0%) as 61.5%, and 34.9% of farmers conducted the regular maintenance by themselves at their house. 3. The reasons for not-fully recognizing operation manual and insufficient before-, during-, after-maintenance of farm machinery were insufficient time for them (45.8%), troublesome (22.9%), unknown maintenance method (16.3%), unknown the necessity for maintenance (12.4%), and others (2.6%) in order. 4. For the annual exchange of engine oil, 3.2 times is necessary but actually 1.7 times was exchanged for power tiller, 4.3 times is necessary but actually 1.9 times was exchanged for farm tractor, 2.7 times is necessary but actually 1.7 times was exchanged for rice transplanter, 2.2 times is necessary but actually 2.3 times was exchanged combine harvester. 5. For the annual cleanness or exchange of fuel filter, 3.2 times is necessary but actually 1.1 times was done for power tiller, 4.3 times is necessary but actually 1.6 times was done for farm tractor, 2.7 times is necessary but actually 1.7 times was done for rice transplanter, 1.9 times is necessary but actually 0.8 times was done for combine harvester. 6. For the annual cleanness or exchange of air filter, 3.2 times is necessary but actually 1.4 times was done for power tiller, 4.2 times is necessary but actually 2.4 times was done for farm tractor, 2.6 times is necessary but actually 1.6 times was done for rice transplanter, 3.9 times is necessary but actually 7.0 times was done for combine harvester. 7. For the experience of breakdown related to maintenance, 5.3% of farmers experienced breakdown due to the insufficient exchange of engine oil, 7.7% of farmers experienced breakdown due to the insufficient cleanness or exchange of fuel filter, and 2.9% of farmers experienced breakdown due to the insufficient cleanness or exchange of air filter. 8. Most farmers (76.1%) recognized the necessity for agricultural machinery training or education, and most farmers preferred about one week for the training period, simple or ease maintenance for the training level, agricultural technical center or agricultural machinery manufacturer for the training agency. 9. Complete recognition of operation manual and sufficient before-, during-, and after-maintenance for farm machinery can minimize the breakdown as well as conduct suitable period farming, enlarge the endurance, prevent the safety accidents, and promote productivity of farm machinery. Therefore, these can be accomplished by the thorough training or education for agricultural machinery.