자주식 양파정식기 정식 메커니즘에 따른 기구학적 해석

카말라술 ( Kamal Rasool ),나피울이슬람 ( Md. Nafiul Islam ),모하마드알리 ( Mohammod Ali ),밀론초두리 ( Milon Chowdhury ),임승진 ( Seung-jin Lim ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.2

The demand of the onion transplanter is increasing in Korea as mechanization rate of the transplantation is less than 2% ~ 5%. Seedling transplanting mechanism is the key component of onion transplanter. Therefore, kinematic analysis of transplanting mechanism is helpful to determine the operational efficiency and performance of the implement. The purpose of this study is to develope kinematic models and simulation analysis of three different transplanting mechanisms. Five bar transplanting mechanism with pushing type seedling extraction, five bar transplanting mechanism with pin type seedling extraction, and four bar transplanting mechanism with clamp type seedling extraction were considered and their motions were simulated using commercial software. Selection of the appropriate link combination was done by conducting five numbers of trials for each mechanism with different lengths of link bars. The simulated velocities and accelerations of the end effector for each mechanism in the ‘X’ and ‘Y’ directions for appropriate link combination were found as 0.3 m/sec, 0.5 m/sec, 0.36 m/sec, 0.73 m/sec, 1.29 m/sec. 1.27 m/sec and 3.9 m/sec2, 1.6 m/sec2, 4.5 m/sec2, 4.7 m/sec2, 7.34 m/sec2, 7.26 m/sec2 respectively. The maximum seedling extraction rates were found as 60, 60 and 30 seedlings per minute, respectively. The five bar transplanting mechanism with pushing type seedling extraction could be considered as appropriate picking mechanism for onion seedling transplantation at 60 rpm speed of the driving link.

IoT를 이용한 사막 토양에서의 벼 재배를 위한 센서 기반 자동관개제어 시스템

모하마드알리 ( Mohammod Ali ),카말라술 ( Kamal Rasool ),밀론초두리 ( Milon Chowdhury ),정재혁 ( Jae-hyeok Jeong ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.1

Automatic irrigation according to the water demand is an efficient way to manage the water loss and ensure the rice quality and productivity in desert soil. Therefore, the aim of the study was to develop a sensor-based automatic irrigation control system for rice production in desert soil using Internet of Things (IoT). Field experiment was conducted in tropical desert area located at United Arab Emirates University (UAEU) farm site at Al-Foah, Al-Ain, UAE. A Linux based VPS system on Raspberry Pi 3 model B+ platform was used to implement the irrigation control unit. Python programming language was used for automation purpose. Commercial soil water content sensor (ECH20 EC-5) and relays were interfaced with the raspberry GPIO pins which were responsible to switch motor on/off. The water content percentage (%) ranging from 25~30% were considered for the rice growth in the desert soil. The output value of the water content sensors were posted and stored on the dedicated web server. The irrigation system operated based on the developed algorithm which autonomously maintain the required soil water content level in the dessert soil depending on their out put values. The pump were observed to be in operation when soil water content level dropped down below the 25% and vice versa. The proposed study based on IoT helped to display the current water content (%) and the status of pump operation (on/off). The smart irrigation system would be suitable to monitor the moisture content for rice cultivation in desert soil.

수경 작물 재배 시스템의 양액 조제에 영향을 미치는 요인 식별

밀론초두리 ( Milon Chowdhury ),카말라술 ( Kamal Rasool ),모하마드알리 ( Mohammod Ali ),나딘알리칸 ( Nadeen Ali Khan ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.1

Automatic target hydroponic solution preparation is still a critical issue as several factors affect this process. The objective of this study was to identify the major factors affecting the target nutrient solution preparation, in terms of nutrient mixing method, coefficients identification, and stock solutions supply rate, for hydroponic crop cultivation. A hydroponic nutrient solution preparation test bench was fabricated, which consisted of sensors, tanks, pumps, pipes, and a controller. Two control methods, on/off and PID, were implemented and coefficients of the relevant control methods, dead-band for the on/off, and Kp, Ki, Kd for the PID method, were identified through mathematical simulations. Validation tests were performed to select the suitable control method along with their coefficients based on the response time and steady-state error. Effects of different stock solution supply rates (0.03, 0.05, and 0.1 Lmin-1) on the control methods were also evaluated. In the on/off and PID control method, the target ion concentration was maintained with the errors of 22.15% and -1.241%, respectively. Considering 2% dead-band for on/off method, and tuning the PID coefficient, the steady-state error reduced to 1.175% and -0.398%, respectively. In the case of on/off control, duration of oscillation and overshoot volume were increased with stock solutions supply rate. In the PID control, the low supply rate (0.03 Lmin-1) showed the minimum steady-state error (-0.402%), but took a long time to reach steady (364s). The Rising time for the high supply rate (0.1 Lmin-1) was short (89s), but the steady-state error was high (-1.363%). The results indicate that the nutrient mixing method, relevant coefficient/s identification, and supply rate of the stock solutions need to be adjusted system-specifically.

온실 내 온습도환경관리를 위한 제어인터페이스 성능평가

장영균 ( Young-kyun Jang ),카말라술 ( Kamal Rasool ),밀론초두리 ( Milon Chowdhury ),정재혁 ( Jae-hyeok Jeong ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.1

우리나라는 과채류, 화훼 등의 작물을 집약적으로 생산하는 시설원예 온실이 1950년대부터 2000년도까지 온실 규모가 급증가하였다. 국내에서는 2000년도 이전부터 네덜란드의 ICT 기반의 스마트팜 기술이 도입된 스마트 온실이 보급, 활용되었고, 시설원예 환경관리를 위한 복합환경제어기는 대부분 네덜란드, 이스라엘 등의 수입산이며, 초기 구축비용이 고가제품으로 고장시 수리 또한 힘들어 실질적으로 농가가 사용하는 불편함이 많이 겪고 있는 실정이다. 본 연구에서는 이러한 문제점을 해결하기 위해 온실 내부 구동기가 센싱 값에 따라 자동제어가 가능한 H/W를 설계, 제작하고, 자동제어알고리즘을 적용하여 PID 제어방법으로 온실 내 온습도 관리 여부를 확인하고자 한다. 위와 같은 문제를 해결하기 위해 제어인터페이스를 저가형으로 오픈소스 형태이고 간편 교체가 가능한 아두이노 마이크로컨트롤러를 사용하고, 제어장치의 고장문제를 해결하기위한 릴레이 교체 또는 추가를 통해 손쉽게 구동기 교체가 가능하도록 10A 릴레이를 이용하여 하드웨어를 설계 및 제작하였다. 제어인터페이스는 온실 내외부의 온습도 환경요인을 센서를 통해 자동 측정하고, 제어기에 입력된 환경관리 목표값에 따라 각종 구동장치를 가동시켜 온실 내부의 환경을 최적 관리하며, 센싱 값에 대한 구동기가 희망온도 27℃, 희망습도 60%를 설정하고 온도를 관리하는 유동팬, 냉난방기, 습도를 관리하는 제습기, 가습기를 작동시킨 결과, 1시간 이내에 온도 5%, 습도가 오차범위 2% 이내에서 지속적으로 유지되는 것을 확인할 수 있었고, 목표 수치에서 온습도 변화에 따라 잦은 구동이 반복되기때문에, PID 제어방법을 이용하여 온도, 습도의 상호작용을 통한 정밀제어가 가능하다는 것을 확인하였다.

Theoretical Analysis of Bending Stresses to Design a Sprocket for Transportation Part of a Chinese Cabbage Collector

이예슬,ALI MOHAMMOD,Md Nafiul Islam,Kamal Rasool,장보은,Md Shaha Nur Kabir,강태경,정선옥 한국농업기계학회 2020 바이오시스템공학 Vol.45 No.2

Purpose Force calculation, stress, and fatigue analysis are major issues in machine design to ensure the life expectancy of sprocket-gear power transmission systems. Therefore, this study aims to conduct a theoretical analysis of bending stresses to select the size and component materials for the power transmission part of a Chinese cabbage collector that is under development. Methods The three-dimensional models of a 14T sprocket gear for two steel materials, SCr420H and SM45C, were generated, employing commercial software. The bending stresses, deformations, and fatigue damages of the designed sprocket were determined by varying the face width and pressure angle of the sprocket teeth. The Lewis and American Gear Manufacturer Association (AGMA) equations were used to calculate the bending stresses. The calculated bending-stress values were compared with the stress values obtained from finite-element analysis (FEA). Results The maximum stress values on the gear teeth were 650.07, 826.23, and 840.77 MPa for a 20° pressure angle by using the Lewis, AGMA, and FEA methods, respectively. The simulated maximum stress value was higher than the yield strength of the SM45C steel and lower than the yield strength of the SCr420H steel. In addition, the maximum face width showed the minimum bending stress and fatigue damage for the selected material. Hence, considering the safety factor, the steel material SCr420H was selected with a 4.5-mm face width for designing the power transmission part of the Chinese cabbage collector. Conclusion The analysis of bending stresses presented in this research can guide the design of a sprocket for the efficient transfer of Chinese cabbages using the proposed Chinese cabbage collector.

트랙터 부착형 배추 수집기 횡전도각 분석

장보은 ( Bo-eun Jang ),카말라술 ( Kamal Rasool ),이상희 ( Sang-hee Lee ),박주택 ( Ju-taek Park ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.1

트랙터 및 농작업기계 보급 확대와 발전으로 인해 사망 사고발생이 증가하고 있으며, 농업기계 농작업 사고유형 중 전복 인한 사고가 36.8%로 큰 비율을 차지하고 있다. 또한 작업 시 트랙터의 전도 문제는 경사지의 기계화 추진뿐만 아니라 작업 안전의 관점에서도 중요하다. 본 연구에서는 트랙터 부착형 배추 수집기 주행상의 안정성을 분석하기 위한 것으로서, 동역학 분석 프로그램을 이용한 시뮬레이션 및 실제 전도시험을 통하여 시작기의 안정성을 평가하였다. 배추 수집기의 주행 안정성 분석을 위하여 동역학 분석 프로그램을 활용하여 횡전도각 시뮬레이션을 진행하였다. 무게 중심은 이론식을 통해 계산되었으며, X축 방향으로 1.32 m, Y축 방향으로 0.9 m에 위치한다. 컨베이어 각도에 따른 기체의 횡전도 분석을 위해 컨베이어의 각도가 0°, 45°, 90°인 경우 시뮬레이션을 각각 3회씩 반복하여 수행하였다. 실증시험을 위한 트랙터 부착형 배추 수집기의 전도시험 또한 컨베이어의 각도 0°, 45°, 90° 일 때 측면별 각 5회씩 반복하여 전도시험을 수행하였다. Recurdyn을 통한 측면 별 횡전도각 시뮬레이션 결과, 배추 수집기가 우측으로 기울어질 때의 횡전도각은 각각 53.49°, 53.32°, 52.59°으로 나타났으며, 좌측으로 기울어질 때 컨베이어 각도별 횡전도각은 각각 12.28°, 32.49°, 40.45°으로 나타났다. 좌측으로 배추 수집기가 기울어질 때 수집기 컨베이어의 길이로 인해 횡전도각이 12° 이상으로 기울어지기 시작하면 그라운드에 접하였다. 전도시험 결과, 배추 수집기가 우측으로 기울어질 때의 횡전도각은 각각 31.20°, 22.40°, 31.15°이었고, 좌측으로 기울어질 때의 횡전도각은 15.11°, 20.60°, 30.92°였다. 시뮬레이션 결과와 비슷하게 좌측으로 기울어질 때는 컨베이어가 바닥에 닿아 컨베이어가 완전히 펴진 상태, 즉 작업 상태에서 기울어질 때에는 지면에 충돌할 위험성이 크다고 판단된다. 횡전도 분석 결과, 컨베이어의 각도가 0°, 45°, 90°로 설정되었을 때 15.11° ~ 31.20° 범위를 가지었으며, 이는 ISO 16251-2 기준에 충족되는 것으로 판단되었다. 추후 배추의 적재, 주행 속도 등을 고려한 동적 시뮬레이션 및 실차 시험을 통해 안정성이 보장된 시작품 개발에 도움을 줄 수 있을 것이다.

Sensor-Based Nutrient Recirculation for Aeroponic Lettuce Cultivation

Chowdhury Milon,ISLAM MD NAFIUL,Reza Md Nasim,ALI MOHAMMOD,Rasool Kamal,Kiraga Shafik,이대현,정선옥 한국농업기계학회 2021 바이오시스템공학 Vol.46 No.1

Purpose The objective of this study was to investigate the effects of used-nutrient solution recirculation on nutrient efficiency improvement and reduction of environmental pollution of an ion-selective electrodes (ISEs)-based recycle-type aeroponic crop cultivation system. Methods A recycle-type aeroponic crop cultivation test bench was fabricated, which consisted of K+, NO3-, and Ca2+ ISEs, pH, and EC sensor, and lettuce were cultivated for inspecting the nutrient solution recirculation process. The specific growth rate of lettuce was evaluated. Different percentages of the used-solution (20%, 40%, 60%, 80%, and 100% of the target volume) were recirculated to find a proper recirculation volume for maintaining the target nutrient level with the minimum supply of stock solutions. The nutrient saving percentage was determined by comparing the nutrient solution requirement with the open-type aeroponic system and open-field cultivation practices. Reduction of environmental pollution was assessed based on the possible environmental pollutions (i.e., surface water pollution, groundwater contamination, and contaminant deposition in the human body), which could be occurred by the direct discharge of the hydroponic nutrient solution. Results The minimum amount of stock solutions were required during the 60%used-solution recirculation. The nutrient solution requirement of the recycle-type aeroponic system was almost 3 to 5 times less than the open-type aeroponic system, and 3 to 6 times less than open-field cultivation based on nutrient consumption rates at different growth stages. An open-type aeroponic system might require more nutrient solution than the open-field cultivation practices based on the frequency of nutrient solution supply in the crop root zone. Although, the discharged nutrient solution increased the K+, NO3-, andCa2+ ion levels a little in the considered surface water reservoir, groundwater, and human body, long-term discharge of the high concentrated hydroponic nutrient solution would be hazardous. Conclusion The findings of this study showed that the nutrient saving efficiency of a recycle-type crop cultivation system is higher compared to the open-type and conventional cultivation practices, which can minimize the cultivation cost notably, and the environmental pollutions can be reduced significantly through the sensor-based nutrient management.

Analysis of Driving Stability and Vibration of a 20-kW Self-Propelled 1-Row Chinese Cabbage Harvester

ALI MOHAMMOD,이예슬,Chowdhury Milon,KHAN NADEEM ALI,Swe Khine Myat,Rasool Kamal,Kabir Md Shaha Nur,이대현,정선옥 한국농업기계학회 2021 바이오시스템공학 Vol.46 No.1

Purpose Overturning and high vibration levels are major causes of agricultural farm fatalities and mechanical troubles during operation. This study assessed the stability angles of a self-propelled 1-row Chinese cabbage harvester and measured the vibration levels for safety under different conditions. Methods The stability of the Chinese cabbage harvester was investigated using computational methods, and the vibration levels were measured on off-road and field conditions. The three-dimensional model of the Chinese cabbage harvester was designed and simulated to evaluate the static stability angles employing commercial software. The relationship between vehicle and deformable soil was calculated using the empirical models. The critical angles and the climbing ability of the developed harvester were examined under loaded and unloaded conditions. The vibration exposures were measured on the cabbage conveyor and the power transmission part in static, off-road, and field operation conditions under various speeds and slopes. Results The stability simulation results showed the minimum lateral stability angles of the harvester were pointed on the loaded condition compared to the unloaded condition. The maximum sideways overturning angle of the Chinese cabbage harvester was recorded as 32° at 150° ground angle and 30° at 270° ground angle, from the moving directions clockwise, for unloaded and loaded conditions. The high levels of vibration were measured at 0.19, 1.64, and 1.38 m/s2 for static, off-road, and field conditions at high speeds among X-, Y-, and Z-axis directions, respectively. Besides, the considerable vector sum (Av) exposures were calculated 1.54, 2.14, and 2.48 m/s2 at 0.3, 0.6, and 0.9 m/s forward speeds on the cabbage conveyor part. Conclusion The concept and guidelines of this research could help to protect operators from safety risks and expose vibration characteristics during farm operations of the self-propelled Chinese cabbage harvester prototype.

농업용 소형 궤도차량 동력전달시스템 효율성 분석

모하마드알리 ( Mohammod Ali ),나피울이슬람 ( Md. Nafiul Islam ),카말라술 ( Kamal Rasool ),밀론초두리 ( Milon Chowdhury ),나딤알리칸 ( Nadeem Ali Khan ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.2

Optimization of the power transmission parts is essential for the development of a multi-functional platform for an agricultural track vehicle. However, the goals of the study were to design the gears and to evaluate the power transmission efficiency using computational simulation methods. The 3D models of a 10, 20, 30, 40, 50T spiral bevel gear were generated using steel material SM45C, employing the commercial software. The power transmission efficiency was calculated varying the gear teeth number, face width, and motor speeds maintaining the electric vehicle powertrain directions. The gear modules of 2.2, 2.7, and 3.2 were used to design the selected gears following a 1:1 gear ratio. The power transmission efficiency of the introduced vehicle was simulated using 1000, 2000, 3000, and 4000 rpm speeds. The simulation results of a 3.2 mm module with 50T showed better performance with maximum power loss at a high rotational speed. The maximum power transmission efficiency was recorded to be 99.95% when adjusted for 4000 rpm rotational speed. The designed gears with 30 mm and 20 mm face width achieved 99.91% and 99.93% transmission efficiency, respectively. The software-based analysis of power transmission gears would provide guidelines for the optimal design of the introduced agricultural utility vehicle.