• 농업과학연구
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• 제37권1호
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• pp.113-121
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• 2010

Land consolidation ratio for rice paddy fields reached to 64.7% as of 2008 in Korea, and this also accelerated automation of field machinery. Especially, research on autonomous tractors has been continuously conducted. Tillage is one of the labor-, energy-, and time-consuming field operations. Most important requirements for autonomous tractors would be travelling path planning and electronic system to control the tractor to follow the path. The instruction of computer was required to conduct the tillage operation in field with unmanned traveling tractor. This instruction was coincidently used in the control of the traveling path and the motion of tractor. The objectives of the study were 1) to characterize and model tillage operating sequence, turning pattern, and 2) to develop tillage path formation programs for autonomous tractor and evaluate the performance.

• Journal of Biosystems Engineering
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• 제25권1호
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• pp.55-62
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• 2000

Autonomous farm operation needs to be developed for safety, labor shortage problem, health etc. In this research, an autonomous tractor for tillage was investigated using machine vision and a fuzzy logic controller(FLC). Tractor heading and offset were determined by image processing and a geomagnetic sensor. The FLC took the tractor heading and offset as inputs and generated the steering angle for tractor guidance as output. A color CCD camera was used fro the image processing . The heading and offset were obtained using Hough transform of the G-value color images. 15 fuzzy rules were used for inferencing the tractor steering angle. The tractor was tested in the file and it was proved that the tillage operation could be done autonomously within 20 cm deviation with the machine vision and the FLC.

• 농업과학연구
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• 제43권1호
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• pp.116-126
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• 2016

The objective of this study is to predict the fuel efficiency of an agricultural tractor. The fuel efficiency of the tractor during rotary tillage was predicted using numerical modeling. A numerical model was developed using Simulation X. Based on tractor power flow, numerical modeling consisted of an engine, transmission, PTO (power take off), and hydraulics. The specifications of major components utilized in the numerical model were the same as those of a 71 kW tractor (field test tractor). The load that was inputted for fuel efficiency prediction into the simulation model was obtained from a field test. Fuel efficiency predictions were conducted by comparing field test results and simulation results. In addition, it was performed by dividing the rotary tillage and steering section. Main results are as follows: first, t-values of engine torque were measured to be 0.31 in the rotary tillage and 0.92 in the steering section. Second, t-values of fuel consumption were measured to be 0.51 and 5.41 in the rotary tillage and the steering section, respectively. Finally, t-values of fuel efficiency were measured to be 1.72 and 40 in the rotary tillage and the steering section, respectively. The results show no significant differences with t-values of less than 5% in the rotary tillage. But, it shows significant differences in the steering section. Therefore, simulation for accurate fuel efficiency prediction requires a suitable algorithm or detailed design of the simulation model in the steering section.

• Journal of Biosystems Engineering
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• 제36권6호
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• pp.397-406
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• 2011

In this study, surveys on operation status of the 73 tractors with rated power of over 75 kW from six provinces in Korea were performed to obtain basic data required for development and efficient use of the high-power and high-performance tractors. And types of tractors and implements, operation crops, types of operations, annual operation areas, annual operation days, annual operation hours, operation speeds and widths, and problems and improvements in use were investigated. Most (91.7%) of the tractor surveyed were operated for forage and silage crops such as rice straw, whole barley, rye grass, reed canary grass, sudan grass, and the remains were operated for upland crops such as ginseng, sweet potato, potato, chinese cabbage, radish. Main operations of the tractors were cutting, baling, and wrapping for forage crops, plow tillage, rotary tillage, and manure spreading. About half (47.9%) of the tractors were used exclusively for forage crop harvesting such as forage crop cutting, forage baling, and bale wrapping, 24.5% of the tractors were used exclusively for plow or rotary tillage, and 27.4% of the tractors were used for both forage crop harvesting, and plow or rotary tillage. For the tractors with power ranges of 75~83, 89~94, 98~101, 113, 124 kW, average annual operation areas per tractor for plow tillage, rotary tillage, forage crop harvesting (cutting, baling, wrapping), and manure spreading operations were analyzed as 112.6. 144.8, 158.9. 390.0. 215.6 ha, respectively. and total average annual operation area per tractor was 171.3 ha. Average annual operation days per tractor for those operations were analyzed as 24.1, 28.9, 38.3, 55.4, 33.4, respectively, and total average annual operation days per tractor was 33.6. Average annual operation hours per tractor for them were analyzed as 260.0, 321.6, 408.1, 664.8, 413.8, respectively, and total average annual operation hours per tractor for the all tractors was 377.1. Ranges of operation widths of plow tillage, rotary tillage, forage crop cutting, forage baling, bale wrapping, and manure spreading operations were shown as 1.5~2.6, 2.3~3.0, 1.8~3.2, 1.8~2.0, 1.8~2.3, 3.1~6.6 m, respectively. Ranges of operation speed of plow tillage, rotary tillage, forage crop cutting, forage baling, bale wrapping, and manure spreading were shown as 6~9, 4~11, 9~16, 8~15, 8~17, 12~16 km/h, respectively.

• 농업과학연구
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• 제38권2호
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• pp.343-347
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• 2011

Precise traveling and tillage operation using an autonomous tractor is difficult with the data from the Geographic Information System(GIS) because it does not include the data of the width and inclination of the field to work. The minimum turing radius of the tractor could be different from the value presented by the tractor maker due to the moisture content of the field soil or operators' skill. Two programs were developed to process data obtained with the tillage path measuring system: one for recognizing coordinates of the 4 field corners, and the other for recognizing the minimum turning radius of the tractor.

• Journal of Biosystems Engineering
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• 제36권3호
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• pp.163-170
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• 2011

Analysis of load on major parts of the tractor power drive line is critical for efficient and optimum design of a tractor. The purpose of this study was to evaluate severeness of the tractor PTO driving axle during rotary tillage operation. First, S-N (stress vs. number of cycle) curve of a PTO driving gear was obtained through the fatigue life test using a PTO dynamometer. Second, PTO severeness was evaluated during rotary tillage operation. Torque measurement system was constructed with strain-gauge sensors to measure torque of a PTO axle, an I/O interface to acquire the sensor signals, and an embedded system to calculate severeness. The severeness of PTO was analyzed using measured torque data during rotary tillage. In the PTO gear life fatigue test, breakage time and bending stress of the gear were measured by tooth widths and torque change during the fatigue life test. The S-N curve showed a good linear relationship between bending stress and number of cycle (life) with a coefficient of determination of 0.97. For PTO severenss evaluation, rotary tillage operations were conducted at two PTO rotational speeds (level-1, level-2) under different paddy and upland field sites with different soil conditions. Results of averaged relative severeness for PTO level-1 and PTO level-2 were 1.96 and 3.34, respectively, at paddy field sites, and they were 1.36 and 2.51, respectively, at upland field sites. The results showed that the PTO driving axle experienced more severe load during rotary tillage at paddy fields than at upland sites, and relative severeness was greater at the higher PTO rotational speed under all of the soil conditions.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.54-61
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• 2022

This is a basic study analyzing emissions of an agricultural tractor during tillage operations. In this study, CO, THC, NOx, and PM considered as emission factor were analyzed during plow and rotary tillage operation by the tractor. Engine torque and rotational speed were measured through ECU. Engine power was calculated using engine torque and rotational speed. The emissions was calculated based on the number of units, rated power, load factor, and operating time. Results showed that the load factor was calculated almost twice, which was higher than 0.48. It was also observed that the emission of the tractor was variable for different agricultural operations because tractor loads were different based on operations. There was a difference in emissions due to differences in plow and rotary working hours. To estimate the emission of agricultural tractor based field operations in detail, it is necessary to consider TAF (Transient Adjustment Factor) and DFA (Deterioration factor). In the future, TAF and DFA will be considered to estimate emissions of the agricultural tractor. Finally, results of this study can contribute to the literature to estimate tractor emissions accurately.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.36-45
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• 2022

The aim of this study was to verify an E-driving system of a 44 kW-class electric tractor using agricultural workload data. Workload data were acquired during field test (plow tillage, rotary tillage, loader operation, field driving, asphalt driving) using a conventional tractor with a load measurement system. These workload data were converted to data of a 44 kW-class tractor based on the load factor of the engine. These data were used to verify the design of the E-driving system of an electric tractor. High-load operations such as plow tillage, rotary tillage, and loader operation could be performed at stage L and stage M. High-speed operation (asphalt driving) could be effectively performed at stage H using a rated rotational speed of the motor. As a result, the E-driving system of the electric tractor was possible to perform all major agricultural operations according to gear stages of range shift. Based on results of this research, we plan to develop an electric tractor equipped with an E-driving system and conduct research on actual vehicle verification in the future.

• Journal of Biosystems Engineering
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• 제43권2호
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• pp.83-93
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• 2018

Purpose: This study derived the consumed power and load characteristics of a tillage operation performed in an upland field located in Seomyeon, Chuncheon, Rep. Korea, where potatoes and cabbages were cultivated in two crops. Methods: A plow and rotavator were mounted on a tractor with 23.7 kW of rated power to perform the tillage operation. The work conditions were determined, considering the actual working speed of the tillage operation performed by the local farmers. The power consumption of the rear axle, engine, and power take-off (PTO), PTO torque, and tractive force were measured under each work condition. The consumed power and load characteristics were analyzed using their average values. Results: The rotary-tillage operation consumed more engine power than the plow operation for the same tractor-transmission gear condition. The PTO in the rotary-tillage operation and the rear axle in the plow operation consumed the most power. The power consumption of the engine and the PTO for the rotary-tillage operation tended to increase as the transmission gears of the tractor and the PTO became higher. In contrast, the rear-axle power consumption was insignificant. In addition, the PTO torque tended to rise as the tilling pitch increased. For the plow operation, the drawbar power and the rear axle power accounted for 68-90% of the engine power. The engine and rear axle power, drawbar power, and tractive force tended to rise as the working speed increased. Conclusions: The power consumption and load characteristics differed for the plow and rotary-tillage operations. They may also differ depending on the soil conditions. Therefore, the power consumption and load characteristics in various work environments and regions should be analyzed, and reflected in the design of tractors and working implements. The results derived from this study can be used as a reference for such designs.

• 농업과학연구
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• 제47권4호
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• pp.1135-1145
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• 2020

The purpose of this study was to compare and analyze the emissions of SOx and NH3 for a 78 kW class agricultural tractor during agricultural operations. A real-time monitoring system was constructed for measuring the load data. The field test was conducted during plow and rotary tillage. The working conditions were selected with the transmission gears in M3 Low and M2 High for the plow tillage and L3 High and L3 Low for the rotary tillage. The engine torque and fuel consumption were measured using controller area network (CAN) communication, and the emissions of SOx and NH3 were calculated based on the fuel consumption. As a result of the field tests, the engine torque was higher for the plow tillage than for the rotary tillage. As the gear stage was increased, the engine torque became higher. The emissions of SOx and NH3 were higher for the plow tillage than for the rotary tillage because the fuel consumption increased. Moreover, the emissions of SOx and NH3 tended to be more distributed for the rotary tillage than for the plow tillage. To develop an emission factor for agricultural machinery, it is important to measure reliable emission data during agricultural operations. In a future study, we will collect various emission data using a portable emission measurement system during agricultural operations.