A Study on the Prediction of Driving Performance of Agricultural Tractors Driving on Dry Sand

김지태,임동우,조승제,박영준 한국농업기계학회 2022 바이오시스템공학 Vol.47 No.4

Purpose Agricultural tractors are used for driving and working in various felds. However, studies on predicting the driving performance of agricultural tractors on terrains other than agricultural land are insufcient. Therefore, this study was conducted to predict the driving performance of agricultural tractors on terrains other than agricultural land. Methods The cone index of dry sand was measured using the ASABE standard, which was then used to predict the driving performance of the agricultural tractor. In addition, the performance of an agricultural tractor driving on dry sand was measured using ISO 7464 and agricultural tractors. Results The driving performance of the agricultural tractor predicted using the ASABE standard was found to be higher than the actual driving performance, which was attributed to the diference in the strength and mechanical properties of the terrain. Therefore, the curve ftting for the coefcients known to be related to the terrain in the ASABE standard confrmed a reduction in the error rate by approximately 22.43%—from 30.73 to 8.30%. Conclusion This study derived an empirical equation for predicting the driving performance of an agricultural tractor suitable for dry sand using the ASABE standard and the test results. These results are expected to help predict the driving performance of agricultural tractors on dry sand more accurately.

Research Trends for Performance, Safety, and Comfort Evaluation of Agricultural Tractors: A Review

Kabir, Md. Shaha Nur,Ryu, Myong-Jin,Chung, Sun-Ok,Kim, Yong-Joo,Choi, Chang-Hyun,Hong, Soon-Jung,Sung, Je-Hoon Korean Society for Agricultural Machinery 2014 바이오시스템공학 Vol.39 No.1

Background: Significant technological development and changes happened in the tractor industries. Contrariwise, the test procedures of the major standard development organizations (SDO's) remained unchanged or with a little modification over the years, demanding new tractor test standards or improvement of existing ones for tractor performance, safety, and comfort. Purpose: This study focuses on reviewing the research trends regarding performance, safety and comfort evaluation of agricultural tractors. Based on this review, few recommendations were proposed to revise or improve the current test standards. Review: Tractor power take-off power test using the DC electric dynamometer reduced human error in the testing process and increased the accuracy of the test results. GPS signals were used to determine acceleration and converted into torque. High capacity double extended octagonal ring dynamometer has been designed to measure drawbar forces. Numerical optimization methodology has been used to design three-point hitch. Numerous technologies, driving strategies, and transmission characteristics are being considered for reducing emissions of gaseous and particulate pollutants. Engine emission control technology standards need to be revised to meet the exhaust regulations for agricultural tractors. Finite Element Analysis (FEA) program has been used to design Roll-Over Protective Structures (ROPS). Program and methodology has been presented for testing tractor brake systems. Whole-body vibration emission levels have been found to be very dependent upon the nature of field operation performed, and the test track techniques required development/adaptation to improve their suitability during standardized assessment. Emphasizes should be given to improve visibility and thermal environment inside the cab for tractor operator. Tractors need to be evaluated under electromagnetic compatibility test conditions due to large growing of electronic devices. Research trends reviewed in this paper can be considered for possible revision or improvement of tractor performance, safety, and comfort test standards.

Experimental Evaluation of Transmission Gear Noise in Agricultural Tractors

최찬호,안형종,박영준,유지훈 한국농업기계학회 2023 바이오시스템공학 Vol.48 No.2

Purpose Agricultural tractors have various noise sources, such as engines, transmissions, and hydraulic systems, with engines generally being the largest noise sources. Nonetheless, with the development of engine design technology, transmission gear noise, which was relatively unknown, has become an issue. However, research on the evaluation and analysis of transmission gear noise in agricultural tractors is insuffi cient. Method In this study, a method for evaluating the gear rattle and gear whine noise level of an agricultural transmission was presented. Also gear rattle noise and gear whine noise levels were evaluated and compared for domestic and imported tractors available in South Korea. Results The rotational speed fl uctuation that determines the gear rattle noise level of domestic and imported tractors was 29.9 and 21.5 rpm, respectively. Moreover, comparing the acceleration response of the PTO housing, the average of domestic tractors was 21.9 g and that of imported tractors was 7.7 g, 35% of that of domestic tractors. The overall noise level inside the domestic and imported tractors was measured to be 80 and 72 dBA, respectively, indicating a diff erence of 8 dBA based on the engine-rated rotational speed. Conclusion When the noise level of the gear harmonic component was compared through order tracking analysis, it was experimentally confi rmed that the engine noise contributed the most to the cabin noise of the imported tractor, while the noise of several gear noise contributed more than the engine noise in the domestic tractor.

The reliability Assessment Technique of the Hydraulic Pump for Agricultural Tractor during the Actual Agricultural Operations

( Abu Ayub Siddique ),백승민 ( Seung-min Baek ),이대현 ( Dae-hyun Lee ),김용주 ( Yong-joo Kim ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.2

This study was focused on the development of the reliability test technique for the hydraulic pump of a tractor during major agricultural operations at various driving and PTO gear stages. The hydraulic pressure measurement system was installed on the tractor. The measured hydraulic pressure and engine rotational speed were converted to the equivalent pressure and engine speed for each agricultural operation using a mathematical formula. Also, the overall equivalent pressure and overall engine speed were calculated to determine the acceleration lifetime. Finally, the developed reliability test technique was evaluated by RS-B-0063, which is the existing reliability evaluation standard for agricultural hydraulic gear pumps. The overall equivalent pressure of the hydraulic pump and the engine rotational speed were found around 10.07 MPa and 1,512.93 rpm, respectively. The acceleration factor was calculated using the overall pressure and engine speed accounting for 336. The evaluation results proved that the developed reliability test method for the hydraulic pump of a tractor satisfied the standard criteria. The warranty life was increased 1.64 times and fault-free test time was decreased 22.73 times, which indicate that the developed technique is efficient and economic. Therefore, it could be said that the developed reliability test technique could be applicable to the hydraulic pump of the tractor during agricultural field operations.

농업용 트랙터의 타이어 강성 계수 측정 시스템 개발

전현호 ( Hyeon-ho Jeon ),김용주 ( Young-joo Kim ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.1

Agricultural operation using tractors is mainly conducted in paddy fields or unpaved roads. Operations in paddy fields or unpaved roads creates constant vibrations. The vibrations on a tractor cabin is important regarding the comfort and helath of the operator. Therfore, in order to increase the comfort and health of the operator, research on reducing the vibration on tractor cabin is required. In the case of small and medium-sized tractors used in Korea, there is no vibration control technology such as cabin or axle suspension. Therefore, the role of reducing the vibration of tractor is conducted only by the vehicle's tires. In order to increase comfort of the operator, it is necessary to select an appropriate tire. For this purpose, a lot of tests using real vehicles are generally performed, but these methods are high time and cost consuming. Studies using dynamic models are needed to reduce the cost and time spent. This research is a basic study for developing a dynamic model of an agricultural tractor. A measurement system for measuring the stiffness coefficient of tires was developed. A 38 kW class tractor (M520, Tongyangmoolsan., Co., Ltd., Korea) was selected for the stiffness coefficient measurement. The frame for fixing the tire for measurement was constructed as shown in Fig 1. The tire was fixed on the frame, and a load cell and displacement sensor were attached to measure the amount of tire deformation according to the load. The data of the sensor was measured using DAQ (840B, HBM, Germany). The data measurement was repeated three times. It shows that the stiffness coefficient of the front tire was about 449 and the rear tire was about 643. In the future study, other coefficients such as dampring ratio will be measured to develop the dynamic model of an agricultural tractor.z

Performance Evaluation of a Driving Power Transmission System for 50 kW Narrow Tractors

홍순중,하종규,김용주,Shaha Nur Kabir,서영우,정선옥 한국농업기계학회 2018 바이오시스템공학 Vol.43 No.1

Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission’s power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission’s gear, bearing, and oil seal. The motor’s power was input in the transmission’s input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission’s power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission’s gear, bearing, and oil seal. The motor’s power was input in the transmission’s input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and tra... Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission’s power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission’s gear, bearing, and oil seal. The motor’s power was input in the transmission’s input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.

Safety Factor Simulation of Hydraulic Mechanical Transmission of Agricultural Tractor

( Jeong-hoon Jang ),( Seung-min Baek ),( Sun-ok Chung ),( Chang-hyun Choi ),( Hae-yoon Tak ),( Teak-jin Kim ),( Jong-yeal Shim ),( Tae-ho Han ),( Yong-joo Kim ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Tractors are agricultural machines that perform various farming operations. As the tractors work on various terrains such as slope land, and reclaimed land, uneven field, various types of transmission have been used. Gears are components of transmission and transmit the power of an engine to a machine and offer numerous speed ratios, a compact structure, and high efficiency of power transmission. In the automotive and construction machinery field, powertrain design uses simulation software. However, transmission of tractor design for agricultural applications uses the empirical method because of the wide range of load fluctuations in agricultural fields. Recently, continuously variable transmissions have been widely used in field tractors. The continuously variable transmission is composed of planetary gear system, helical gear sets, hydrostatic unit, and hydraulic values. Planetary gears system is composed of planetary gears, carriers, sun gears, and ring gears, and have various gear ratios according to various combinations of gears. However, planetary gear system has difficulty in designing and assembling. So, virtual modeling and analysis of planetary gear system using simulation software are needed. In this study, the planetary gear system applied in continuously variable transmission of agricultural tractor was developed by using the gear analysis software Romax DESIGNER. In addition, safety factor and lifetime of planetary gear system were evaluated in various input load conditions. Finally, safety factor and lifetime of planetary gear system were compared in various conditions.

Review : Off-Road Machinery System Engineering ; Research Trends for Performance, Safety, and Comfort Evaluation of Agricultural Tractors: A Review

( Shaha Nur Kabir ),( Myong Jin Ryu ),( Sun Ok Chung ),( Yong Joo Kim ),( Chang Hyun Choi ),( Soon Jung Hong ),( Je Hoon Sung ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.1

Background : Significant technological development and changes happened in the tractor industries. Contrariwise, the test procedures of the major standard development organizations (SDO`s) remained unchanged or with a little modification over the years, demanding new tractor test standards or improvement of existing ones for tractor performance, safety, and comfort. Purpose: This study focuses on reviewing the research trends regarding performance, safety and comfort evaluation of agricultural tractors. Based on this review, few recommendations were proposed to revise or improve the current test standards. Review: Tractor power take-off power test using the DC electric dynamometer reduced human error in the testing process and increased the accuracy of the test results. GPS signals were used to determine acceleration and converted into torque. High capacity double extended octagonal ring dynamometer has been designed to measure drawbar forces. Numerical optimization methodology has been used to design three-point hitch. Numerous technologies, driving strategies, and transmission characteristics are being considered for reducing emissions of gaseous and particulate pollutants. Engine emission control technology standards need to be revised to meet the exhaust regulations for agricultural tractors. Finite Element Analysis (FEA) program has been used to design Roll-Over Protective Structures (ROPS). Program and methodology has been presented for testing tractor brake systems. Whole-body vibration emission levels have been found to be very dependent upon the nature of field operation performed, and the test track techniques required development/adaptation to improve their suitability during standardized assessment. Emphasizes should be given to improve visibility and thermal environment inside the cab for tractor operator. Tractors need to be evaluated under electromagnetic compatibility test conditions due to large growing of electronic devices. Research trends reviewed in this paper can be considered for possible revision or improvement of tractor performance, safety, and comfort test standards.

Pre-processing of load data of agricultural tractors during major field operations

Ryu, Myong-Jin,Kabir, Md. Shaha Nur,Choo, Youn-Kug,Chung, Sun-Ok,Kim, Yong-Joo,Ha, Jong-Kyou,Lee, Kyeong-Hwan Institute of Agricultural Science 2015 Korean Journal of Agricultural Science Vol.42 No.1

Development of highly efficient and energy-saving tractors has been one of the issues in agricultural machinery. For design of such tractors, measurement and analysis of load on major power transmission parts of the tractors are the most important pre-requisite tasks. Objective of this study was to perform pre-processing procedures before effective analysis of load data of agricultural tractors (30, 75, and 82 kW) during major field operations such as plow tillage, rotary tillage, baling, bale wrapping, and to select the suitable pre-processing method for the analysis. A load measurement systems, equipped in the tractors, were consisted of strain-gauge, encoder, hydraulic pressure, and radar speed sensors to measure torque and rotational speed levels of transmission input shaft, PTO shaft, and driving axle shafts, pressure of the hydraulic inlet line, and travel speed, respectively. The entire sensor data were collected at a 200-Hz rate. Plow tillage, rotary tillage, baling, wrapping, and loader operations were selected as major field operations of agricultural tractors. Same or different farm works and driving levels were set differently for each of the load measuring experiment. Before load data analysis, pre-processing procedures such as outlier removal, low-pass filtering, and data division were performed. Data beyond the scope of the measuring range of the sensors and the operating range of the power transmission parts were removed. Considering engine and PTO rotational speeds, frequency components greater than 90, 60, and 60 Hz cut off frequencies were low-pass filtered for plow tillage, rotary tillage, and baler operations, respectively. Measured load data were divided into five parts: driving, working, implement up, implement down, and turning. Results of the study would provide useful information for load characteristics of tractors on major field operations.

Development of Driving Simulator for Safety Training of Agricultural Tractor Operators

( Yu Yong Kim ),( Byoung Gap Kim ),( Seung Yeoub Shin ),( Jinoh Kim ),( Sung Hyun Yum ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.4

Purpose: This study was aimed at developing a tractor-driving simulator for the safety training of agricultural tractor operators. Methods: The developed simulator consists of five principal components: mock operator control devices, a data acquisition and processing device, a motion platform, a visual system that displays a computer model of the tractor, a motion platform, and a virtual environment. The control devices of a real tractor cabin were successfully converted into mock operator control devices in which sensors were used for relevant measurements. A 3D computer model of the tractor was also implemented using 3ds Max, tractor dynamics, and the physics of Unity 3D. The visual system consisted of two graphic cards and four monitors for the simultaneous display of the four different sides of a 3D object to the operator. The motion platform was designed with two rotational degrees of freedom to reduce cost, and inverse kinematics was used to calculate the required motor positions and to rotate the platform. The generated virtual environment consisted of roads, traffic signals, buildings, rice paddies, and fields. Results: The effectiveness of the simulator was evaluated by a performance test survey administered to 128 agricultural machinery instructors, 116 of whom considered the simulator as having potential for improving safety training. Conclusions: From the study results, it is concluded that the developed simulator can be effectively used for the safety training of agricultural tractor operators.