• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.292-300
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• 2007

Not many types of roughage cutters have been introduced in Korea so far. However, those machines could not satisfy farmers to cut rice straw or barley wrap-silage properly. Stiffness and firmness of roughage bale were two obstructing factors. In order to solve this problem, a tractor attached cut-feeding machinery for the round baled roughage was developed for dairy and beef cattle farm in Korea. A series of tests were performed and acquired data were analyzed by using the several imported roughage cutters, which have been already introduced in dairy farm in Korea. And, a prototype of forage cutter was selected, analyzed, designed and manufactured to develop a tractor attached roughage cut-feeder for round bale. Also, the prototype machine was tested, modified and improved through revising model. As a result, a tractor attached roughage cut-feeder for round bale was manufactured. In order to evaluate the performance of the model machinery. a series of test were performed by the prototype machinery both at the plant and field. The model machinery developed satisfied in both power requirement and cutting capacity. As a conclusion, one of the obstacles against feeding the round baled roughage in the korea cattle farm can be eliminated by developing the tractor attached round baled roughage cut-feeder.

• Journal of Biosystems Engineering
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• v.14 no.4
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• pp.229-241
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• 1989

The purposes of this study were to develop an electronic-hydraulic draft control system for tractor implements, to investigate the control performance of the system and the possibility of adaptation to the conventional tractor. Experiments were carried out to investigate the responses of the system to the step and sinusoidal inputs in draft control. The effects of control mode, hydraulic flow rate, reference deadband, and proportional constant on control performance of the system were investigated. Moreover, the effects of filtering signals from draft sensor were also investigated. The following conclusions were derived from the study; 1. In draft control, there were hunting problems in controlling the implement without filtering the draft signals. Filtering was performed by a control program of electronic controller and the control performance and stability of the system were improved significantly. 2. For the draft control system operated on on-off control mode, draft was controlled within ${\pm}27-{\pm}55kg_f$ to the reference draft when the hydraulic flow rates were 5-15 l/min. For the draft control system operated on PWM control, draft was controlled within ${\pm}27kg_f$ to the reference draft regardless of hydraulic flow rates. 3. In the frequency responses of the draft control system, control performance on PWM control mode was not better than on on-off control mode because of characteristics of hydraulic valve and drafe sensor. As the hydraulic flow rates increased for the system operated on on-off control mode, the corner frequency of amplitude attenuation increased, but the corner frequency of phase-angle change remained nearly the same. But, the system was unstable beyond the frequency of 3.1 rad/s. 4. The electronic-hydraulic hitch control system developed in this study showed superior control performance, stability and convenience compared to conventional mechanical-hydraulic hitch control system. It is considered to be a superior replacement for the conventional mechanical-hydraulic hitch control system.

• Journal of Biosystems Engineering
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• v.27 no.1
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• pp.11-18
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• 2002

One of the major obstructing factors against managing dairy farm in Korea has been a shortage of roughage supply, which resulted in excessive abuse of concentrate feed. In order to solve this problem, production of the wrap silage by the winter cereal forages raised in the fallow paddy field is strongly recommended in Korea. The main objective is to develop a tractor attached round bale wrapper which can process the silage by wrapping the round bales with thin plastic films. This is the first half of the study which is divided by two parts. In this first part, bale wrapping process was analyzed, and based on this results the followings were designed, developed and tested. 1. Bale wrapper which haying the maximum capacity of 1 ton bale with various functions such as loading, wrapping, discharging the round bales and supplying and cutting wrap films was designed. 2. An actuator and its hydraulic circuit of each process were developed and tested. 3. Also, the variations of hydraulic pressure and engine speed were investigated by operating bale wrapper developed. In this test, maximum pressure of the hydraulic circuit for the bale wrapping was 130 kg/㎠ when it raised the bale, which was quite below the relief pressure of 170 kg/㎠ of hydraulic circuit. In the engine speed test, speed drop was 20∼67 rpm, which meant that there was no over-load operation. Therefore, the experiment proved that developed hydraulic circuit and mechanism is stable in bale wrapping operation

• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.99-106
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• 2002

This study was conducted to improve utilization efficiency of slurry and choose a suitable type of tractor power which can be attached by manure spreader in the paddy field. In the paddy field, the pulling force for the spreader was measured by using a measurement system installed between tractors with and without the spreader. The soil moisture contents at the 0${\sim}$10cm and 10${\sim}$20cm depth of test soil(SiCL) were 28.45% d.b. and 23.47% d.b., respectively in average while Cone Index at l0cm and 15cm depth were 14.5kPa and 16.2kPa, respectively. It was impossible to measure the soil moisture contents and Cone Index below 20cm depth of the soil because the hardness of the soil increased greatly. Thereafter, hard pan of the sampled soil was found at 15${\sim}$20cm depth. While the required power only for the dragged tractor was found to be 3.44kW in the test field, the required pulling powers of tractor considering the pumping were 8.48${\sim}$12.48kW, 12.19${\sim}$16.19kW, 16.96${\sim}$20.96kW, respectively for 2 tons, 3 tons, and 4 tons of tank capacity. As the tank capacity increased, the sinkage of soil were also increased to 7cm, l0cm, and 12cm, respectively for the tractors with 2 tons, 3 tons and 4 tons of tank capacity. Considering about 60% of pulling efficiency of tractor, a tractor which had lower than 25.74kW of pulling power was suitable to pull the spreader and spread the slurry simultaneously for manure spreader with 2 tons of tank capacity. 29.42kW${\sim}$36.78kW of pulling power was found to be optimum for the tractor with 3 tons of tank capacity while over 40.45kW for 4 tons of tank capacity.

• Journal of Korean Society of Forest Science
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• v.88 no.2
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• pp.255-265
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• 1999

This study deals with forest soil characteristics and their effects on the trafficability of logging vehicles. The study area is the national experimental forest located in Kwangnung. This site has 20m length and is equally divided by 5 surveying ranges with 4m width, on which a tractor(FIATAGRI) attached with logging boogie can drive in 4 driving types, namely 1time-return unload, 1time-return with load of 780-790kg weight of 3 logs, 5 and 10times-return with same load. After one driving type on all surveying ranges, the soil hardness is surveyed 5 times with 3 several type tools, SHM-1 type, lang penetrometer(L-PNTM), and clegg impact soil tester(CIST). A disturbed degree of cover vegetation and sliding conditions of vehicle are also observed. As results, the soil type of the test site was SC by USCS and dry brown forest soil. The cover vegetation is gotten trambled under driving after 3-5 times-return, shrubs leaves are fully fallen and their bark are peeled, and after 10 times-return the cover vegetations were nearly disappeared. The test vehicle has neither slided nor was overthrown. The wheel tracks in the 1-3 ranges, of which unit weight(gd, gt) is high and soil moisture content(MC) is low, were only 1-2cm deep, but those in the 4-5 ranges, of which the gd, gt is low and the MC is high, were 5-7cm deep. In the soil hardness test, which was established in 5 test ranges by types of driving, the more driving times, the higher the hardness. The soil hardness surveyed by L-PNTM has changed slowly and that surveyed by SHM-1 type has risen sharply. In the ranges with higher specific gravity(Gs), higher unit weight, lower MC and higher liquid limit(LL) and plasticity index(PI) was the soil hardness high and the trafficability was good. In the ranges with opposite conditions, also in the ranges of the lower soil hardness, the trafficability must be not good, because the wheel track may be deep. The results from CIST attached with 4kg hammer was not better than expected. So it is recommended to use CIST with 2.5kg or 0.5kg hammer.