농업용 트랙터의 차축 구동 토크 예측을 위한 동역학 시뮬레이션 모델 개발

전현호,백승민,백승윤,김용주 대한기계학회 2023 大韓機械學會論文集A Vol.47 No.11

농업용 트랙터는 시장 수요에 맞게 지속적으로 개선 및 개발되고 있다. 이러한 과정에서 트랙터는 다양한 설계 변경이 이루어진다. 설계 변경에 따라 내구성 확보를 위해서는 반드시 성능평가가 수행되어야 한다. 농업기계분야에서는 대부분 시제품을 이용한 성능평가들이 이루어지고 있으며, 이는 많은 시간과 비용을 필요로 한다. 이를 해결하기 위해 최근 시뮬레이션 모델을 이용한 성능평가에 대한 연구가 다양하게 수행되고 있다. 따라서 본 연구에서는 농업용 트랙터의 성능평가를 위해 동역학 시뮬레이션 모델을 개발 및 검증에 대한 연구를 수행하였다. 시뮬레이션 모델 개발은 타이어 계수 측정 시스템 및 계측용 트랙터 개발을 통해 수행되었다. 트랙터 모델 구성은 차량의 제원 및 상용프로그램인 Recurdyn(V9R4, Functionbay Co. Ltd., Korea)을 이용하여 수행하였다. 모델 검증은 시뮬레이션 결과 값 및 계측 값의 평균 차축토크 비교 분석을 통해 수행하였으며, 분석결과 6%의 오차를 보였다. 해당 모델을 이용하여 트랙터의 차축 부하 예측이 가능할 것으로 판단되며, 본 모델은 차후 연구에서 쟁기 및 로타리 등 주요 트랙터 작업 조건에서의 차축 부하 예측에 활용할 예정이다. Agricultural tractors are continuously being developed to improve performance. In this process, the tractor design has to be changed. To secure durability according to the design change, performance evaluation has to be conducted. Performance evaluation using prototypes is mostly conducted in agricultural machinery, which requires a lot of time and money. Various studies on performance evaluation using simulation models have been recently conducted to solve this problem. Therefore, this study is conducted to develop and validate a dynamic simulation model for the performance evaluation of agricultural tractors. The development of the simulation model is conducted through the development of a tire stiffness and a tractor measurement system. The tractor model is configured using the commercial program for dynamics simulation. The simulation model is validated through a comparison of the average axle torque of the simulation result and measurement data. It shows that there was an error of 6. It is deduced that it is possible to predict the axle torque of the tractor using the dynamic simulation model of an agricultural tractor. In future, studies will be conducted using this simulation model to predict the axle torque in conditions of tractor operation such as the plow and rotary tillage.

엔진 부하율에 따른 트랙터 경운 작업 시 배기가스 분석

이준호,전현호,백승윤,백승민,김완수,아윱,김용주 사단법인 유공압건설기계학회 2022 드라이브·컨트롤 Vol.19 No.4

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.

농작업에 따른 78 kW급 농업용 트랙터 엔진 부하율 분석

백승민,김완수,백승윤,전현호,이대현,김형권,김용주 유공압건설기계학회 2022 드라이브·컨트롤 Vol.19 No.1

The purpose of this study was to calculate and analyze the engine load factor of major agricultural operations using a 78 kW class agricultural tractor for estimating the emission of air pollutants and greenhouse. Engine load data were collected using controller area network (CAN) communication. Main agricultural operations were selected as plow tillage (PT), rotary tillage (RT), baler operation (BO), loader operation (LO), driving on soil (DS), and driving on concrete (DC). The engine power was calculated using the measured engine load data. A weight factor was applied to load factor for considering usage ratio according to agricultural operations. Weight factors for different agricultural operations were calculated to be 27.4%, 32.9%, 17.5%, 7.7%, 4.5%, and 10.0% for PT, RT, BO, LO, DS, and DC, respectively. As a result of the field test, load factors were 0.74, 0.93, 0.41, 0.23, 0.27, and 0.21 for PT, RT, BO, LO, DS, and DC, respectively. The engine load factor was the highest for RT. Finally, as a result of applying the weight factor for usage ratio of agricultural operations, the integrated engine load factor was estimated to be 0.63, which was about 1.31 times higher than the conventional applied load factor of 0.48. In future studies, we plan to analyze the engine load factor by considering various horsepower and working conditions of the tractor.

주요 농작업에 따른 78kW급 농업용 트랙터의 소요 동력 분석

김완수,김연수,김택진,박성운,최용,최일수,김영근,김용주 대한기계학회 2019 大韓機械學會論文集A Vol.43 No.12

The aim of this study is to analyze the power requirement of a 78 kW agricultural tractor for the optimal design of a power transmission system. Moldboard plow tillage, disc plow tillage, rotary tillage, baler operation and loader operation are selected as major agricultural operations. The power measurement system is constructed for the driving axle, PTO axle, main hydraulic pump and auxiliary hydraulic pump. The total power requirement for the moldboard plow tillage, disc plow tillage, rotary tillage, baler operation and loader operation are 53.69, 37.50, 65.61, 36.84 and 17.55 kW, respectively. The rotary tillage consumed about 84 % of the engine rated power, with the highest required power compared to other agricultural operations. The power requirement of the driving axle, PTO axle, main hydraulic pump and auxiliary hydraulic pump are 13.6, 31.5, 2.01 and 1.84 kW, respectively. The sum of the power requirements is 48.9 kW, which is 63 % of the engine rated power. 본 연구는 트랙터의 동력전달시스템 최적 설계를 위한 기초연구로써 78kW급 농업용 트랙터의 소요 동력을 분석하기 위하여 수행되었다. 트랙터 소요 동력 계측시스템은 주요 동력 소모원인 차축, 동력 취출 장치, 주 유압펌프, 보조 유압펌프에 대하여 구축하였으며, 필드시험은 주요 농작업기 5종에 대하여 수행하였다. 몰드보드 플라우, 디스크 플라우, 로타리, 베일러, 로더 작업 시 총 소요 동력은 각각 53.69, 37.50, 65.61, 36.84, 17.55kW로 나타났다. 본 연구에서 수행한 농작업 중 로타리 경운 작업에서 엔진 정격출력의 약 84%의 동력 소모로 가장 높은 소요 동력을 나타냈으며, 로타리 경운 작업 외 주요 농작업별 평균 소요 동력은 엔진 정격출력의 70% 미만 수준으로 나타났다. 주요 동력 소모원별 소요 동력은 차축, PTO 축, 주 유압펌프, 보조 유압펌프에서 각각 13.6, 31.5, 2.01, 1.84kW로 나타났으며, 주요 동력 소모원의 소요 합은 48.9kW로, 정격 출력의 63%를 사용한 것으로 나타났다.

55㎾급 농업용 트랙터 정유압 기계식 변속기 설계

백승민(Seung Min Baek),김완수(Wan Soo Kim),김연수(Yeon Soo Kim),백승윤(Seung Yun Baek),김용주(Yong Joo Kim) 유공압건설기계학회 2020 드라이브·컨트롤 Vol.17 No.2

The purpose of this study was to suggest design criteria for the HMT (hydro-mechanical transmission) of a 55 ㎾-class agricultural tractor, develop a simulation model, and evaluate its performance such as axle rotational speed, tractor speed, and power transmission efficiency. In this study, the HMT comprised a compound planetary gear and a HSU (hydro-static unit), and the compound planetary gear comprised two planetary gear sets. The HMT has three gear stages, and the maximum tractor speed was selected as 40 km/h. The simulation time was set at 2736 hours considering the lifetime of the tractor, and the simulation was performed for each gear stage at the engine-rated power conditions. As a result of the simulation, the axle rotational speeds for each gear stage were 39, 77, and 158 rpm, respectively. The range of tractor speed for each gear stage were 1.05-10.22 ㎞/h, 10.74-20.17 ㎞/h, and 20.70-41.40 ㎞/h, respectively. The APE (absolute percentage gear) for the tractor’s maximum speed between target value and simulation results were 2.20%, 0.85%, and 3.50%, respectively. Also, the power transmission efficiency for each gear stage were 0-75%, 72-81%, and 69-81%, respectively. The simulation results for the power transmission efficiency of the HMT were similar with the results of the previous research. This was a basic study on the development of the HMT for an agricultural tractor. In future studies, it is necessary to develop a tractor platform and evaluate the performance. The comparison between the simulation model and the HMT tractor should be performed.

Magic formula를 이용한 트랙터 타이어-아스팔트의 견인력 예측 모델 개발

김지태 ( Ji-tae Kim ),안다빈 ( Da-vin Ahn ),김경대 ( Kyeong-dae Kim ),조승제 ( Seung-je Cho ),박영준 ( Young-jun Park ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1

차량의 주행성능은 차량의 주행장치와 노면의 역학적 상호작용에 의해 결정된다. 농업용 트랙터(이하 트랙터)는 주로 농지에서 농작업 시 운용되기 때문에 트랙터 주행성능(견인력, 견인효율) 예측에 관한 연구는 트랙터 타이어-토양의 역학적 상호작용에 초점을 두고 수행되었다. 하지만, 트랙터는 농작업 이외에도 이동, 운송 등 다양한 분야에서 활용되고 있으며 아스팔트 도로 위를 주행하는 경우도 빈번히 발생한다. 하지만, 트랙터 타이어-아스팔트의 역학적 상호작용에 관한 연구결과는 미비한 실정이며, 아스팔트 위를 주행하는 트랙터의 주행성능 예측은 승용 차량 타이어-아스팔트의 역학적 상호작용을 통하여 수행되고 있다. 따라서, 아스팔트 도로 위를 주행하는 트랙터의 안정성 및 주행성능 예측을 위해서 트랙터 타이어-아스팔트의 역학적 상호작용에 관한 연구가 필요하다. 본 연구에서는 트랙터 타이어-아스팔트의 상호작용 분석을 위해 magic formula를 사용하였다. 80 kW급 트랙터의 견인시험(KS B ISO 7464:1983)을 통해 아스팔트를 주행하는 트랙터의 슬립에 따른 견인력을 측정하였으며, 이를 통해 트랙터 타이어-아스팔트 magic formula parameter를 도출하였다.

55kW급 농업용 트랙터 정유압 기계식 변속기 설계

백승민,김완수,김연수,백승윤,김용주 사단법인 유공압건설기계학회 2020 드라이브·컨트롤 Vol.17 No.2

The purpose of this study was to suggest design criteria for the HMT (hydro-mechanical transmission) of a 55 kW-class agricultural tractor, develop a simulation model, and evaluate its performance such as axle rotational speed, tractor speed, and power transmission efficiency. In this study, the HMT comprised a compound planetary gear and a HSU (hydro-static unit), and the compound planetary gear comprised two planetary gear sets. The HMT has three gear stages, and the maximum tractor speed was selected as 40 km/h. The simulation time was set at 2736 hours considering the lifetime of the tractor, and the simulation was performed for each gear stage at the engine-rated power conditions. As a result of the simulation, the axle rotational speeds for each gear stage were 39, 77, and 158 rpm, respectively. The range of tractor speed for each gear stage were 1.05-10.22 km/h, 10.74-20.17 km/h, and 20.70-41.40 km/h, respectively. The APE (absolute percentage gear) for the tractor’s maximum speed between target value and simulation results were 2.20%, 0.85%, and 3.50%, respectively. Also, the power transmission efficiency for each gear stage were 0-75%, 72-81%, and 69-81%, respectively. The simulation results for the power transmission efficiency of the HMT were similar with the results of the previous research. This was a basic study on the development of the HMT for an agricultural tractor. In future studies, it is necessary to develop a tractor platform and evaluate the performance. The comparison between the simulation model and the HMT tractor should be performed.

농업용 트랙터 진동 저감을 위한 실험적 연구

박현우(Park, H. W.),문남수(Moon, N. S.),정봉수(Jeong, B. S.),박진성(Park, J. S.),김병진(Kim, B. J.) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10

The vibration that occurs when starting the agricultural tractor is raised more than double compared to the general situation. In this case, impulsive vibration make the machines life to be shortened, which can cause a drivers physical problems also. Therefore, in this paper, we have taken an effective way to reduce the impulsive vibration that occurs when starting a agricultural tractor. As a result, we confirmed that appling the anti-vibration pads and the high stiffness engine mounts is effective method to reduce the impulsive vibration.

농업용 트랙터 듀얼 클러치 변속기의 동력전달 효율 분석에 관한 연구

문석표,문상곤,김재승,손종현,김용주,김수철 유공압건설기계학회 2022 드라이브·컨트롤 Vol.19 No.1

The aim of this study was to conduct basic research on the development of a dual-clutch transmission(DCT) and automatic transmission for agricultural tractors. The DCT layout and the DCT simulation model were developed using commercial software. Power transmission efficiency of the DCT and component power loss were analyzed to verify the developed simulation model. Power loss analysis of the components was conducted according to previous studies and ISO(International Organization for Standardization) standards. The power transmission efficiency of the DCT simulation model was 68.4–91.5% according to the gear range. The power loss in the gear, bearing, and clutch DCT system components was 0.75–1.49 kW, 0.77–2.99 kW, and 5.24–10.52 kW, respectively. The developed simulation model not include the rear axle, differential gear, final reduction gear. Therefore actual power transmission efficiency of DCT will be decreased. In a future study, an actual DCT can be developed through the simulation model in this study, and optimization design of DCT can be possible by comparing simulation results and actual vehicle test.

농업용트랙터 ROPS 시험의 신뢰성 향상을 위한 측정불확도 추정

임류갑,강영선,김택진 사단법인 유공압건설기계학회 2023 드라이브·컨트롤 Vol.20 No.1

The agricultural tractor ROPS test method according to OECD code 4 is a test to assess whether the driver's safety area can be secured when a tractor overturns, and reliability should be ensured. In this study, a model formula and procedure for calculating measurement uncertainty expressing reliability in the field of agricultural machinery testing were established according to the ISO/IEC Guide 98-3:2008. The characteristics of the ROPS test device were assessed and repeated tests were performed, and the were used as factors to calculate the measurement uncertainty. As a result of repeated tests, the accuracy was higher than 1.9 % in all load directions; thus, they were, applied to calculate the type A standard uncertainty. The final expanded uncertainty was calculated within the range of less than ± 7.76 kN of force and ± 6.96 mm of deformation in all load directions.