• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.2
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• pp.53-58
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• 2005

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1127-1136
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• 1993

A mathematical model has been developed for the simulation of static stability of agricultural tractors. The model was based on Reichmann's model but modified to improve its shortcomings for practical applications. Two examples of model simulation were presented and showed its usefulness in evaluating the control and stability loss boundaries.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.284-287
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• 2006

We consider the transportation problem of optimizing the use of trailers and tractors. Several variants with fixed loading and unloading time are discussed. We show that the variant requiring on-time delivery can be solved in polynomial time, whereas the other variant requiring time-window delivery is NP-hard. We also discuss that if the number of loading and unloading operations assigned to each trailer or tractor is limited, even the variant requiring on-time delivery becomes NP-hard.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.20-32
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• 1982

This survey was conducted to investigate the present status of farm tractor utilization for obtaining a basic reference to the establishment of the government's agricultural mechanization strategies. Thirty two counties from the eight provinces except Jeju were covered in this study. From these selected areas, 433 sample farms having farm tractor were taken to obtain the general informations by the enquete, and 93 sample farms among them to investigate the status of daily tractor use in the year of 1980. The analyzed results are summarized as follows: 1. Farm tractors owned by the rice-oriented farms holds 71.5 percent of the total number of tractors the livestock-oriented farms 17.0 percent, and the orchard-oriented farms 7.0 percent. Among the farm tractors 64.3 percent was a large size (46ps) and 35.7 percent a small size(19~23ps). 2. Most of the tractors surveyed were equipped with the essential attachments such as plow and rotavator. About 18 percent of the tractor owners had no trailer, which seemed too high considering the large percentage of tractor use for transportation. The availability of other attachments was very low except a grader on the rice-oriented farms and a hay harvester and a front loader on the livestock-oriented farms. 3. The average size of farm was 3.9 hectare for the rice-oriented farms, 13.9 hectare for the livestock-oriented farms and 7.4 hectare for the orchard-oriented farms. It was obious that the average farm size of was too small compared to the theoretical machine capacity of the tractors. 4. About 70 percent of the tractor operators were in the age of twenties and thirties. About 90 percent of them had an educational level of middle school graduate or above even though their technical level was very low. 5. Any particular problem in tractor use was not found in this survey. From the farmer's preference for purchasing a new tractor, however, it is estimated the demand on a 20-30ps tractor will be more increased. 6. The average annual use of tractor was of about 100 days or 400 hours. It appeared that the rice-oriented farms used most with 412.4 hours per year, and followed by the livestock-oriented farms with 403.6 hours, the orchard oriented farms with 377.7 hours. 7. Among the total hours of tractor use, 47.3 percent was for transportation, and 41.6 percent was for plowing and rotary tillage. The largest portion of the annual tractor use was taken by transportation on the livestock-oriented farms, by land preperation on the rice-oriented farms, and by loading and chemical spraying on the orchard-oriented farms. 8. The hours of tractor use had a peak in May. The hours of use for own farm was remarkably different among the different farm oriented, but there was no considerable difference between the too different sizes of tractor. 9. The hours of tractor use decreased as the age of the operator or the educational level increased. The reason might be that the operators who had a high educational level or were older had a tendency of disliking custom works. 10. The average custom use of tractor was 171.3 hours per year, and the ratio of custom work was 63.7 percent on the rice-oriented farms, 31.7 percent on the livestock-oriented farms and 22.4 percent on the orchard-oriented farms. Among the custom works, the most popular one was the grader leveling. 11. The charge on custom work was about 40,000 Won per hectare for plowing and rotary tillage, and it was the most expensive in the southeastern region, and next followed by the southwestern region. 12. The average plowing capacity of the small tractor was 7.8 hours per hectare in the paddy field, and that of the large tractors was 4.3 hours per hectare. The average rotary-tilling capacities of the small and the large tractors were 6.5 and 4.3 hours per hectare, in the paddy field respectively.

• Journal of Biosystems Engineering
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• v.33 no.3
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• pp.151-156
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• 2008

This study was conducted to evaluate ride vibrations experienced by tractor operators during plowing, rotovating, and transporting operations in Korea. Field data of ride vibrations were taken at the operator-seat interface from 49 tractors and analyzed on the basis of ISO 2631-1 and EU Directive 2002/44. Of the measured ride vibrations 15.4% in the plowing and 12.5% in farm road transport exceeded the 8-hour fatigue decreased proficiency boundary in the fore and aft directions at frequencies from 1 to 5 Hz. 93.9% exceeded the 8-hour potential health risk of ISO 2631-1. The ride vibrations exceeding the 8-hour exposure limit were 38.5% in plowing, 31.6% in rotovating, 100% in farm road transport and 88.9% in concrete road transport. Although most tractor operators were not exposed to ride vibrations greater than the 8-hour exposure limit value (ELV) of EU Directive 2002/44, 7.7% of the operators in the plowing experienced greater vibrations than the ELV in the fore-aft direction. Farm road transport produced greater vibrations than any other operations. Concrete road transport, plowing and rotovating operations followed next. Limit criteria for ride vibration exposure differ depending upon the guidelines. Exposure limit of the health guidance caution zone of ISO 2631-1 is lowest among its kinds.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.63-71
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• 2015

Path planning is an essential part for traveling and mowing of autonomous lawn mower tractors. Objectives of the paper were to analyze operation patterns by a skilled farmer, to extract and optimize waypoints, and to demonstrate generation of formatted planned path for autonomous lawn mower tractors. A 27-HP mower tractor was operated by a skilled farmer on grass fields. To measure tractor travel and operation characteristics, an RTK-GPS antenna with a 6-cm RMS error, an inertia motion sensing unit, a gyro compass, a wheel angle sensor, and a mower on/off sensor were mounted on the mower tractor, and all the data were collected at a 10-Hz rate. All the sensor data were transferred through a software program to show the status immediately on the notebook. Planned path was generated using the program parameter settings, mileage and time calculations, and the travel path was plotted using developed software. Based on the human operation patterns, path planning algorithm was suggested for autonomous mower tractor. Finally path generation was demonstrated in a formatted file and graphic display. After optimizing the path planning, a decrease in distance about 13% and saving of the working time about 30% was achieved. Field test data showed some overlap, especially in the turning areas. Results of the study would be useful to implement an autonomous mower tractor, but further research needs to improve the performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.181-186
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• 2013

In recent years, eco-friendliness and high fuel economy have become important issues for commercial tractors. Electric tractors are often required for operation in a greenhouse. However, the battery capacity limits the available operation time. To overcome this problem, a plug-in hybrid electric tractor is considered a reasonable alternative. This tractor has a basic driving ability and can operate in various working modes such as mower, rotary, loader, and trailing. This study focuses on the energy management strategy by considering various working modes.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.2-5
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• 1996

Orissa is one of the major rice growing states of India. The state covers an area of 15.54 mha with 6.00mha cultivable holding is 1.46 ha. The power input is much below the national average of 0.87 hp/ha. Recently, the Government of Orissa has accorded equal status to Agriculture as given to the Industry with determination to increase the power input for agricultural production to2.54 hp/ha so as to obtain an average rice productivity of 3.0t/ha. Appropriate power units so as to be available with in the purchasing power of the small size farm owners in lieu of a pair of bullocks appear to be the right approach and is found to be in line with the highly successful Japanese and Korean model of small farm mechanization . The state needs 0.25m units of small tillers and tractors per year. The present population of tractors and power tillers in the state is about 11000nos. In India, two manufactures in collaboration with Japanese firms started manufacturing of power tiller sin 197 . The present production of power tillers in the country is about 1000 unit per year which is inadequate to meet the demands of all the stats. To meet the demands of the Orissa state, three Chinese model power tillers imported by local agencies are being supplied to the farmers during the past two years. Encouraged by the demand of power tillers in the state, three local manufacturing units located at Bhubanewar have come up with their own model of light weight power tillers(1.5 to 3.0 hp) during the past one year. These machine have been evaluated in the farms of the university and have been found to be promising . There is a target of supplying during 1996-97. The local manufacturers are in need of international collaboration for technical knowhow to manufacture these machine economically to meet the requirement of the farmers.

• Journal of Biosystems Engineering
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• v.27 no.6
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• pp.537-546
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• 2002

In this study an automatic soil hardness measuring system mountable on agricultural tractors was developed to improve the accuracy of manual soil hardness testers by a constant penetrating rate, right direction of the cone-penetrometer and the isolation of vibration from the operator. This was necessary to supply similar experimental condition for performance test of new model and comparative experiment. The results of the study are summaried as follows; 1. The system consisted of a sensing part of soil hardness, a driving part of the measuring system and an attaching part between the tractor and the measuring system. 2. The allowable limit value of the system developed was set to 392N to protect from breaking the serve motor and the coupling used in this system. 3. The driving shaft penetrated into soil by 0.3m to measure soil hardness. The soil hardness was measured at the depth of 0.3m from the soil surface but the penetrating work was stopped and the driving shaft was pulled out to protect the system when the value of the soil hardness was too big on foreign substances like stones or straws. 4. Two values measured by automatic measuring system developed in this research and manual penetrometer were compared by statistics hypothesis testing method. When two people measured the soil hardness at the depth of 0.1 and 0.15m by manual cone penetrometer, there was no relationship between two values by two people but the values at the same depths by automatic measuring system developed showed similarity. The automatic system, therefore, developed in this research was proper for measuring soil hardness.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.3
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• pp.222-230
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• 1995

This study was canied out to ddermine optimum areas for various sizes of land coverage of the farm machinery utilization in 1993-1994. A kind of machinery size and work systems were classed as the power tiller of 10HP+man power, the tractor of 35~46HP (tractor of 64~86HP and attachment were leased to harvest work), 64-86HP+ attachment and 90- 105HP+ attachment, respectively. \ulcornerhe results are summarized as follows: 1. The optimum areas of tractors of 90~105HP, 64~86HP and the power tiller of lOHP were estimated as 21.9 (corn-rye cropping system)- 26.9ha (sorghum $\times$ sudangrass - rye cropping system), 14.7 - 22.8ha and 1.2 - 1.61ha, respectively. The break-even-point areas of the tractors of 90-105HP. 64-86HP and the power tiller of lOHP were 16.6 (corn-rye cropping system)- 19.9ha (sorghum $\times$ sudangrass - rye cropping system), 12.5 - 16.lha and 0.12-0.13ha, respectively. 2. The optimum areas (land sizes, annual field capacity) for 50 cows by feeding rate(%) of roughage to concentrate were 6.8ha, 13.6ha in the 4060, 8.5ha, 17.0ha in the 5050 and 10.2ha, 20.4ha in the 60:40, and in case of 30 cows, it were 4.lha, 8.2ha in the 40:60, respectively. In the former case for the form of work system was the trador of 90-105HP+attachment and 64~86HP+ attachment, and the latter was the tractor of 35~46HP (tractor of 64~86HP and attachment were leased to harvest work) and 64-86HP+ attachment. 3. Productiori cost for corn-rye cropping system reducted to 51.8% in 102.9 wonkg dry matter the tractor of 90~ 105HP+ attachment with 213.4 wonkg dry matter the power tiller of 10HP+ man power.