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샤피크키라가 ( Shafik Kiraga ),레자나심 ( Nasim Reza ),초두리밀런 ( Milon Chowdhury ),구란다즈아스라푸자만 ( Gulandaz Md Ashrafuzzaman ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.2
Chinese cabbage is a commercially valuable crop due to its various uses. Among its important quality parameters is mass, which can be used in the development of yield maps for yield monitoring. Previous research focused mostly on the use of load cell(s) and stereo-based approaches for mass estimation. This study aimed to propose a new method of mass estimation using three HY-SRF05 ultrasonic sensors, and compare it’s performance to that of a single load cell under laboratory conditions. An impact plate was fabricated and installed to receive impact of Cabbage as it dropped off an inclined conveyor. The load cell was calibrated with different loads and achieved an R2 fit of 0.986. Cabbage mass was calculated from the load cell signals. The effects of different dropping heights, plate angles, and conveyor speeds were also investigated. On the same conveyor, three sensors, two installed opposite to each other and at the top, were first calibrated using known distances, and then used to measure Cabbage length and thickness. Cabbage mass was calculated from its volume assuming an elliptical shape.. The proposed method had a mass estimation accuracy greater than 91%, slightly lower than that for the load cell’s 95%. The proposed method showed potential for mass estimation.
농업 4륜 전기 자동차 설계를 위한 환감 기어의 부하 분석
알리모하마드 ( Mohammod Ali ),이슬람나피울 ( Md. Nafiul Islam ),레자나심 ( Md Nasim Reza ),초두리밀론 ( Milon Chowdhury ),이슬람수마이야 ( Sumaiya Islam ),이현석 ( Hyun-seok Lee ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1
The load analysis of gears is a major challenge to ensure the reliability of the power transmission system of the all-wheel-drive electric vehicle. It is necessary to select the proper material and face width for design the reduction gears to avoid its failure during field operations. Therefore, this study aimed to investigate the suitable materials and dimensions, to evaluate the fatigue life regarding the level of damage. A field experiment was conducted on the off-road conditions following the driving speeds. A load (torque) measurement method was established to collect the torque data using torque sensors and data acquisition systems. A load duration distribution (LDD) method was used to analyze the torque data to examine the cyclic load characteristics. The Palmgren-Miner cumulative damage model was used to determine the fatigue damage level of the reduction gears. The hypothetic fatigue life was recorded up to 2500 hours that satisfied the actual service life of the agricultural vehicle. In order to the analyses, the steel material ‘SCr420H’ with a 5 mm face width gear was suitable for a 10-year vehicle service life. The results presented in this study can suggest the service life of a four-wheeled electric vehicle for agricultural use.
농업용 붐 분무기의 노즐 높이 및 분무 균일 성 측정을 위한 초음파 센서에 대한 온도의 영향
샤피크키라가 ( Shafik Kiraga ),레자나심 ( Md Nasim Reza ),초두리밀런 ( Milon Chowdhury ),이슬람나피울 ( Md Nafiul Islam ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1
The increasing popularity of boom height controllers requires a desired nozzle height above the spray targets for effective spraying. The objective of this study was to determine the effect of temperature on nozzle height measurement using ultrasonic sensors and the impact on spray uniformity. Experiments were carried out with a constant nozzle spacing of 50 cm and a pressure of 600 kPa considering temperature compensation and non-compensation states of ultrasonic sensor measurements. Nozzle heights of 30, 50, and 70 cm were selected for reference. Two measurements were carried out for each selected height with a temperature compensated and non-compensated state at 15, 25, and 300C. The spray distribution was also determined for each measurements. Coefficient of Variation (CV) and percent measurement error (ME) were used to characterize spray uniformity and temperature effect on height measurement. The estimated heights with temperature compensation were closer to the reference heights, which exhibits a low ME. The ME increased from low to high temperatures. Temperature compensated heights resulted in more even spraying trends, with lower CV values accompanied by non-compensated heights. Our findings showed that, ultrasonic sensors need temperature correction for proper Nozzle height measurement and optimal spray distribution.
알리모하마드 ( Mohammod Ali ),아스라푸자만구란다즈 ( Gulandaz Md Ashrafuzzaman ),레자나심 ( Md Nasim Reza ),하비네자엘리에젤 ( Habineza Eliezel ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.1
To ensure the durability of gears a fatigue analysis is essential to avoid failure during field operations under various dynamic loads. Therefore, the objective of the study was to conduct a theoretical fatigue analysis of spiral bevel gear to calculate the service life of the power transmission part of a utility track vehicle that is under development. A field experiment was performed to measure the applied load (torque) of the gear in various agricultural operations. A torque measurement system was developed to collect the axle torque data of the vehicle. The load duration distribution (LDD) method was applied to analyze the torque data to assess cyclic load characteristics. The Palmgren-Miner cumulative damage model was employed to predict fatigue failure levels of spiral bevel gears. The fatigue life under an empty platform with the driver, a lawnmower, a sprayer-trailer (150-L payload), and a lawnmower and 150-L payload trailer was recorded from 13,000 to 25,000 h approximately, which was a sufficient lifespan range of gears for 12-years service life. According to the analyses, the gears met the standard service life during field operations with attached implements. The results provided in this study can be used to design power transmission systems of utility vehicles for multipurpose agricultural operations.
Development of soil water content monitoring system using Raspberry Pi and Arduino communication
하비네자엘리에젤 ( Eliezel Habineza ),알리모하마드 ( Mohammod Ali ),아흐메드샤리아르 ( Shahriar Ahmed ),레자나심 ( Md Nasim Reza ),장영윤 ( Young Yoon Jang ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.2
Soil water content is a key requirement for plant growth and development. Monitoring the soil water content continuously at several locations may offer accurate water variability data for irrigation scheduling. The aim of the study was to design and fabricate an automated data acquisition system for monitoring the variations of soil water content within the experimental soil bin through Raspberry Pi and Arduino serial communication. For evaluating the sand soil water content variability, a soil bin test bench (3m*3m) containing sandy soil was built and 90 soil water content sensors were inserted at different depths of 10, 20, 30, 40, and 50 cm, respectively. For water supply in the soil bin, a drip irrigation system containing 3 rows (60 cm inter-row distance) with 5 drippers each pipeline with 30 cm intervals, was designed. Raspberry Pi (Pi4 model B+) and three Arduino (Mega 2560) were interfaced with sensors and the data were obtained using python programing language. The data was automatically recorded in the external Pi-memory for further processing and remote monitoring was performed using a Raspberry Pi VPN system. During the experiment, the maximum and minimum averages of the ambient temperature, humidity, and the soil water content values were recorded and found to be 42.1±3 to 32.7±3°C, 75±2 to 42.9±4% and 60.91±2 to 26.95±1%, respectively. The water content percentages varied at different depths of sandy soil due to pressure difference, flow rate, and water infiltration rate. The designed automatic irrigation monitoring system would help to monitor water variability in soil.