• Journal of Biosystems Engineering
• /
• 제34권5호
• /
• pp.297-304
• /
• 2009

This study was conducted to investigate the adequacy of the representative empirical models which are developed for predicting the tractive performance of the tractor operating in various soil conditions. Four representative empirical models which are widely used in the traction prediction of tractor were selected through literature review. Four models were Wismer-Luth, Brixius, Dwyer and Hernandez model, which were empirical traction models of a single wheel. The efficacy of four models were confirmed via comparison of the tractions of tractor predicted using the four models with those measured from traction tests which were conducted for two different driving type (2WD and 4WD) of the tractor on two different soil conditions. The results showed that tractions predicted by Brixius' model, especially for slip range under 20% which the operating efficiency of a tractor is very high, were well consistent with the ones measured from traction test better than the tractions predicted by models which are proposed by Wismer-Luth, Dwyer and Hernandez.

• Journal of Biosystems Engineering
• /
• 제29권5호
• /
• pp.407-418
• /
• 2004

There are several different types of continuously variable transmission(CVT) such as toroidal drive, belt drive, hydrostatic drive, hydro-mechanical drive. The toroidal CVT is an alternative to the manual transmission, HST, power-shift gear trans-missions or other CVTs. The driver of the CVT tractor doesn't have to operate a shia lever since the CVT controller automatically controls the speed of tractor. Thus, it is much easier to operate the CVT tractor. The fuel efficiency of CVT tractor can be increased since the controller responds quickly to the change in external load on the wheel during field operation. This study was conducted to develop the hardwares and softwares for the toroidal CVT controller which control the variator and the range clutches. The hardware consisted of a measurement system, hydraulic system and computer. And the PID controller was developed using the simulation model of the CVT control system. Through the simulation, the control coefficients for the PID controller were selected. Finally, the performance of the CVT control system was evaluated by step response test and torque response test. The settling time of the CVT control system appeared to be fast enough for field operations.

• Journal of Biosystems Engineering
• /
• 제24권3호
• /
• pp.209-216
• /
• 1999

A self-travelling sprayer was developed to avoid the exposure of an operator to agricultural chemicals and exhaust gas, to improve safety and to increase working efficiency during the application and transport work in the greenhouses. This system consists of self-travelling system and the control system for application and safety device. The auto-spray car is equipped with a liquid chemical tank of 80l capacity. The travelling system adopted mechanical steering system which link mechanism of front wheel is guided by guide rollers. The sprayer travels along the guiding pipe which is set on the furrow in the greenhouses. The sprayer stops automatically applying and traveling when the liquid chemical tank becomes empty or when the sprayer reach the turning point. The spray booms swings in a vertical plane. The control system of safety devices controls the automatic stop of the sprayer when there is an obstacle on the traveling path, or when the battery becomes discharged. The auto-spray car traveled smoothly and steadily along the guide pipe during traveling straightly and turning on the ground.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
• /
• pp.538-545
• /
• 1993

Individual farming involving small land parcel (0.5 to 1.0ha) is declining because it is uneconomic and unable to incorporate modern technological innovation to improve its production efficiency. A centrally managed medium scale mechanised rice share farming was implemented at Permatang Pauh, Sebeerang Perai, Malaysia in 1988-1991 for eight seasons on a contiguous 57 ha rice land rented from 100 owners. Ten participants were chosen to participate in this project which perpetuated from revolving fund of MR 165.000. The objective of the project was to overcome problem of production efficiency and to provide a stable income to farmers operating on a medium and full time basis. Mechanisation was given prime emphasis to optime and reduce labour requirement and meeting the targeted crop scheduling. Direct seeding and mechanical transplanting methods of crop establishment were adopted. Land preparations, crop establishment and crop care were done using machineries purchased by the group. Selected participants were trained to operate machineries which composed 2 and 4 wheel tractors, mechanical transplanters, motorised seeders and sprayers. Harvesting and transportation of rice to the mills were done on contractual basis using combine harvesters and bulk handling via 3-4 ton lorries respectively. The net clean yield (less 10-20 percent deduction at rice mills) obtained in such project has contributed to stabilise the production and income of participating farmers.

• Journal of Biosystems Engineering
• /
• 제33권5호
• /
• pp.355-361
• /
• 2008

As agricultural machinery has become larger and tillage practices have changed in recent decades, compaction as a result of wheel traffic and tillage has caused increasing concern. If strategies to manage compaction, such as deep tillage, could be applied only where needed, economic and environmental benefits would result. For such site-specific compaction management to occur, compacted areas within fields must be efficiently sensed and mapped. We previously developed an on-the-go soil strength profile sensor (SSPS) for this purpose. The SSPS measures within-field variability in soil strength at five soil depths up to 50 cm. Determining the variability structure of SSPS data is needed for site-specific field management since the variability structure determines the required intensity of data collection and is related to the delineation of compaction management zones. In this paper, soil bin data were analyzed by a spectral analysis technique to determine the variability structure of the SSPS data, and to investigate causes and implications of this variability. In the soil bin, we observed a repeating pattern due to soil fracture with an approximate 12- to 19-cm period, especially at the 10-cm depth, possibly due to cyclic development of soil fracture on this interval. These findings will facilitate interpretation of soil strength data and enhance application of the SSPS.

• 농업과학연구
• /
• 제37권1호
• /
• pp.37-43
• /
• 2010

This study carried out to develop barrier-free certification program in forest trail. It is done to provide the certification system presented about certification organized, certification standard and indexes, evaluation method and operation plan. In order to develop certification program in forest trail, detailed measurement index must be developed earlier based on an accessbility, a stability, a preservation and a walking continuity. The suitable forest trail for weak pedestrian was investigated that running slope should be 1/20(5%) maximum, cross slope cannot exceed 1/50(2%) maximum and clear tread width should be above of minimum 90cm. In addition, the trail type is designed as a mixed trail system which is a combination of the loop and the line form and its distance should be 225~675m. Finally, forest trail should be manage sustainably by having regular monitoring and evaluation.

• 한국정밀공학회지
• /
• 제25권4호
• /
• pp.108-117
• /
• 2008

A transmission designed with P.T.O(Power Take-Off) axle for agricultural work vehicles including multi-purpose vehicles has been developed. It is focused on the 4-wheel drive transmission of synchronous contact type for practical use in fruit tree households which is required for a large-sized agricultural vehicle. Concerning to the specification performed, the load capacity is from 500kg to 1,000kg and the safety should be secured for passengers. In addition, the driving condition should also be secured under bad situations of the topographic slope, swampy land and the rest. In order to carry out above tests, a prototype vehicle through strength analysis of transmission design has been manufactured. Consequently, optimal design conditions on the power transmission with multi-purpose vehicle for various jobs are proposed such as an indication of optimal RPM and torque at a certain work situation. The performance test through the prototype of multi-purpose work vehicle is performed and the related data base is achieved. Finally, it is improved on troubles by the analysis of the results of R&D and provided the solutions on problems occurring to mass production in the future.

• Journal of Biosystems Engineering
• /
• 제41권4호
• /
• pp.281-287
• /
• 2016

Purpose: The purpose of this study is to develop a walking-type two-row sesame reaper, which can simultaneously perform the cutting and collecting of sesame plants and other crops like perilla and soybean. Methods: The factors involved in reaping sesame were determined experimentally in order to design a prototype of the sesame reaper. The prototype is made up of four parts for cutting, conveying, collecting, and running. The height of two disc-plate saw blades on the cutting part is adjusted by an adjusting wheel, and peripheral speed is adjusted in accordance with the running speed. The conveying belt of the conveying part can be tilted from $0^{\circ}$ to $90^{\circ}$. The collecting part extracts a predetermined amount of transferred sesame plants. The prototype was used to evaluate the performance at different working speeds, so that the work efficiency can be calculated. Results: The center of gravity of the sesame plants was 900 mm, measured from the end of the cut stem. The diameter of the disc-plate saw blade was determined to be 355 mm, peripheral speed was 20.4-32.7 m/s, and the picking height of the conveying belt for sesame was 130 mm. The performance of transfer and collection of the sesame, when the insertion angles were $60^{\circ}$ and $90^{\circ}$, proved to be excellent. However, when the angle was over $120^{\circ}$, the performance was only 75-80%. The performance was at 100% efficiency when the ratio between running speed and conveying belt speed of the prototype was 1:2, which seems to be the ideal ratio for the sesame reaper. Conclusions: A sesame reaper was developed, which can integrate the processes of cutting, conveying, and collecting, by investigating and considering various factors involved in the reaping process. The sesame reaper can reduce the costs for yielding and producing sesame due to its highly efficient performance.

• Journal of Biosystems Engineering
• /
• 제14권2호
• /
• pp.85-93
• /
• 1989

This study was intended to develop the system which controls header height of combine automatically by means of sensing the difference between the header and the ground surface. A micro-computer was used for the controller. The sensing unit designed for the study was composed of potentiometer, oscillating link, and gage wheel. An electric-hydraulic circuit was driven by microcomputer to control header height of combine. Performance of the control system was tested by computer simulation, stationary operation of header, and traveling on the simulated ground.

• Journal of Biosystems Engineering
• /
• 제32권4호
• /
• pp.223-229
• /
• 2007

This study was conducted to develop a 2 row type band furrow tiller for a walking cultivator. The tillage and weeding operations in the furrow of dry fields has been done manually or chemical herbicide has been applied. The application of herbicide induces soil pollution and manual operation requires heavy labor. This 2-row type implement was developed to substitute this manual operation and to minimize soil pollution. The developed implement was composed of power transmitting device, tilling device, frame and tail wheel. The max. plowing width and depth were 300mm and 180mm, respectively. The revolutions of the hexagonal shaft and the tillage shaft were $227{\sim}376rpm$ and $355{\sim}590rpm$, respectively. The adequate working speed was $0.50{\sim}0.83m/s$ and the field capacity was $0.17{\sim}0.28hr/10a$.