• Korean Journal of Agricultural Science
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• v.47 no.1
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• pp.43-58
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• 2020

Mulching plastic is used for the purpose of maintaining soil temperature, moisture, and weed and pest prevention in agriculture. Any remaining plastic after use may contaminate the soil and damage crop growth. To solve this problem, mulching plastic wrappers have been studied and developed, but the actual use rate is quite low due to their poor performance and frequent tearing of the plastic on the field. In this study, we developed a tractor attachable mulching plastic wrapper to minimize the tearing of the mulched plastic. The developed mulching plastic wrapper consists of hydraulic motors and pumps, valves, a microcontroller, and sensors. The collecting speed of the plastic mulch was calculated considering the tractor's travel speed and the radius of the collecting drum. A proportional controller was designed to control the rotating speed of the hydraulic motor as the plastic was wound around the collection drum and the radius increased. The performance of an indoor experiment was quite promising because the difference between the collecting speed predicted by the calculation and the actual collecting speed was 2.71 rpm. Based on a field verification test, the speed difference was max. 14.28 rpm; thus, the, proportional integral derivative (PID) controller needs to be considered to control the drum speed precisely. Another issue was found when the soil covered at the edge of the plastic was hardened or the road surface was uneven, the speed control was unstable, and the plastic was torn. In future research, vibrational plows will be equipped to break-up the harden soil for collecting the plastic smoothly.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.111-116
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• 2003

토양 경도는 작물의 성장 특히, 뿌리의 성장에 큰 영향을 미친다. 토양의 경도가 증가함에 따라 작물의 수량이 감소되는 현상은 많은 연구에서 보고된 바 있다. 따라서 작물에 따라 적절한 토양 경도를 유지하는 일은 대단히 중요하다. 최근, 정밀 농업에 대한 관심이 증가됨에 따라 토양과 작물의 상태를 정확히 나타낼 수 있는 다양한 변수가 연구되고 있으나, 아직까지 단 하나의 변수로써 생육 상태를 정확히 나타낼 수는 없다. 토양 경도도 작물의 생육 상태에 영향을 미치는 변수로서, 그 영향을 구명할 필요가 있다. (중략)

• Journal of Biosystems Engineering
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• v.25 no.2
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• pp.79-88
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• 2000

Effects on tractive performance of design parameters of cage wheel as a traction aid to driving tires of tractor in wet paddy field were investigated experimentally. an experimental cage wheel was designed so that the design parameters such as wheel diameter, wheel width, lug pitch and lug angle could be varied during traction test, The traction test was conducted in two different types of wet paddy field ; shallow and deep harpan fields . Experimental results showed that tractive performance is affected by both soil conditions and the design parameters. A considerable improvement on the tractive performance was obtained by using a cage wheel with 45$^{\circ}$ lug angle in shallow hardpan and smaller lug pitch in deep hardpan. The diameter of cage wheel was mostly influential to the tractive performance both in shallow and deep hardpans.

• Journal of Biosystems Engineering
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• v.31 no.4 s.117
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• pp.334-341
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• 2006

This study designed to develop a mower which can reach to side of a tractor or inclined road side and operate weeding. The prototype consists of 4 parts; the base and turning equipment, the boom, the arm, the weeder. The hydraulic actuators were divided into two operations, weeding and operation of boom and they were controlled by electrical equipment. Weeding was very effective when pressure set up at $15{\ell}/min$ using weeding, as $2.27kg{\cdot}m$, 2,210rpm. Weeding range of flail mower was 1.1 to 2.6m from the center of turning equipment at a flat. In case of disk mower, it was 1.5 to 2m. As a result of operation test, flail mower was appropriate for weeding at fence and short weeds, disk mower was appropriate for long weeds.

• Journal of Biosystems Engineering
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• v.26 no.4
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• pp.337-354
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• 2001

This study was conducted in order to develop a Chinese cabbage harvester attachable to tractors. For designing Chinese cabbage harvester in which laboratory and field tests were conducted with to determine feasible values design factors. To adopt the various sizer of C-cabbages, U-type soft rubber band was attached to the chain conveyor with an angle. Required torque of the conveyor axle was about 206-210kgf$.$cm. And the required peripheral speed of the disk cutter was 6.54m/s or more to have a clean session in root cutting. Three different harvest method were tested. The best harvesting method with minimum pulling force and damage was disk cutting flying just above the soil surface were the cut chinese cabbages are transferring to the holding conveyor attached soft rubber lug in prompt. Theoretical speed ratio of the tractor travel and feed of a chain conveyor was 1:1.2 with the attaching angle of 30 degree and 1:1.1 with the angle of 20 degree. Actual field experiment showed the speed ratio of 1:1.5 was the best because of the slip effect.

• Journal of Biosystems Engineering
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• v.26 no.1
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• pp.1-10
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• 2001

Interactions between cage wheel and soil under the wet paddy field condition were analyzed. The cage wheel as a traction aid to driving tires of tractor was attached to the outside of the tires. The driving torque transmitted only to the cage wheel was measured and its effect on the total driving torque by both the tires and cage wheel was analyzed. Mathematical models were developed to predict the soil thrusts y a single lug and by the cage wheel with many lugs, respectively. Experimental results showed that as the diameter of cage wheel increased, positive effects of the cage wheel on the traction also increased. About 33-40% of the total traction force was obtained by the cage wheel with a diameter 1,182mm and 49-55% with a diameter 1,222mm. The peak thrust of the single lug of cage wheel increased by 31% and 59%, respectively when the diameter of the cage wheel increased from 1,182mm to 1,222mm and 1,262mm. The thrust by the cage wheel was estimated by using the developed mathematical models and the results were proved that the models are reliable for the estimation of the traction by the cage wheels.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.501-508
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• 2010

A swirl chamber type diesel engine attachable to 18 kW agricultural tractors was improved to reduce exhaust emissions. Compression ratio and throat area ratio of the combustion chamber were varied to determine optimum combustion conditions. Tests were composed of full load and 8-mode emission tests. Compression ratio was fixed as 21, but the swirl chamber volume was increased by 3.8%. Output power, torque, specific fuel consumption, exhaust gas temperature, and smoke level were not considerably different for compression ratios of 21.5 (reference condition) and 21 (test condition), while NOx, HC, CO and PM levels for the compression ratio of 21 were decreased by 11%, 46%, 28%, 11%, respectively, from those for the compression ratio of 21.5. The tests were also conducted with a compression ratio of 22 and 4.3% increased chamber volume. Output power, torque, exhaust gas temperature and smoke level were greater, while specific fuel consumption was less for the compression ratio of 22 than those for the compression ratio of 21.5. Increase of compression ratio decreased HC and CO levels by 24%, 39%, but increased NOx and PM levels by 24%, 39%. Based on these results, a compression ratio of 21 was selected as an optimum value. Then, full load tests with the selected compression ratio of 21 were carried out for different throat ratios of 1.0%, 1.1%, 1.2%. Output power and torque were greatest and smoke was lowest when throat area ratio was 1.1%, which satisfied the target values of specific fuel consumption (less than 272 g/$kW{\cdot}h$) and exhaust gas temperature (less than $550^{\circ}C$). Therefore, a throat area ratio of 1.1% was selected as an optimum value.

• Journal of Biosystems Engineering
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• v.36 no.1
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• pp.9-14
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• 2011

This study was carried out to develop a vine crusher for harvesting sweet potato. The experimental two-row vine crusher attachable to agricultural tractor composed of vine crushing part with frail type vine crushing blades and vine lifting blades, power transmission part with chain and gear transmission mechanism, crushing height control part with two control wheels and manual levers, and implement frames, was designed and fabricated. And this vine crushing performance was also analyzed. From vine crushing tests, backward travel direction (i.e., rotational direction of the vine crushing blades) showed better vine crushing performance than forward travel direction. Crushing ratio of remained vine was increased, and length of remained vine and length of crushed vine were decreased as working speed was decreased and rotational speed of vine crushing blades was increased. At a working speed of 0.27 m/s and rotational speed of vine crushing blades of 800 rpm, crushing ratio of remained vine was 98%, length of remained vine was 104 mm, and length of crushed vine was 327 mm. But, when crushing vine on irregular ridges, vines and mulching vinyl were wound in the vine crushing part. Therefore, change of location of power transmission chain mechanism, and an automatic control device for controlling crushing height were needed.