• Agricultural and Biosystems Engineering
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• v.5 no.2
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• pp.40-44
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• 2004

This study was conducted to solve the problem of spinach harvesting done by manpower at the outdoor field during the cold winter season. Prototype spinach harvester was designed to dig, pick-up, and collect in a continuous operation for harvesting outdoor field-planted crawling type spinach. In the field test, two types of blades (Type A : angle of $150^{\circ}$, Type B : straight) were used for measuring the cutting loads of spinach and chain conveyor with lugs was used for picking up the root cut spinach. Prototype's vibrating blade reduced the digging power of the fixed blade by $46\%$. The loss was also very little ($0.7\%$) with a digging depth of 4 cm, an oscillation frequency of 748 rpm, and an oscillation distance of 33 mm. The working performance of the prototype spinach harvester was 38 hour/ha resulting to $96\%$ labor cost reduction compared to the conventional harvesting.

• Journal of Drive and Control
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• v.19 no.1
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• pp.26-33
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• 2022

This study dealt with a self-propelled spinach harvester, which is capable of carrying out sequential harvesting work. This study aimed to find the cause of the harvester's occasional performance deterioration, which occurs in the process of simplifying the hydraulic circuit, using a multi-domain analysis model. The study was carried out in the following manner. First, a hydraulic system analysis model, which combines linear motion, rotary motion, hydrodynamic behavior, and an electrical signal, was developed through SimulationX software, specialized in multi-domain analysis. Second, a scenario for single behavior and coupled behavior was set out on an actuator basis. Third, the flow rate of the hydraulic system, which is not required for the movement of the actuator, was quantitatively analyzed. The results showed that a change in oil temperature was the cause of the harvester's occasional performance deterioration. And the higher the oil temperature, the more serious the performance deterioration, especially as the number of actuators operated simultaneously was small.

• Journal of Biosystems Engineering
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• v.30 no.4 s.111
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• pp.210-219
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• 2005

This study was conducted to solve the problem of crawled spinach harvesting that had been mainly done by manpower on the outdoor fields during the winter season. Moreover, there are not enough workers available for farming at most of rural areas in Korea because farming is getting hard and the number of old-aged workers is increasing. In order to find appropriate methods of digging, picking and collecting of spinach, the tests were examined outdoors. A prototype was designed based on the results of the tests and then fabricated for digging, picking-up and then collecting in continuous operation for harvesting spinach planted in the outdoor fields. In the field test with the prototype, the vibration intensity transmitted to the driver by vibrating blade was low while the vibrating blade reduced digging power by $46\%$ compared to that of the fixed blade. The spinach loss was found to be as low as $0.7\%$ in the condition of digging depth of 40 mm, cam rotational velocity of 748 rpm, and blade amplitude of 16.5 m. The working performance of the prototype spinach harvester was found to be 3.8 hour/10a resulting in $96\%$ of labor saving and $85\%$ of operating cost compared to the conventional manual harvesting.

• Journal of Drive and Control
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• v.19 no.1
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• pp.69-75
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• 2022

This study aimed to develop solutions for the intermittent performance deterioration of self-propelled spinach harvesters through analysis model. The study was conducted in the following manner. First, changes in performance deterioration and surplus flow, which result from oil temperature changes, were analyzed by simulating actual sequential harvesting movements, which involve driving with actuators operated simultaneously, by analysis model developed in a previous study. Second, fundamental solutions for surplus flow problems were presented. Third, the solutions were applied to a virtual environment to present their practicality and quantitative effects. The two solutions based on the study results were as follows. First, a closed center-type directional control valve was applied to the hydraulic circuit. Second, an unloading system was set up through an on-off solenoid valve.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.193-198
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• 2003

가. 시금치를 기계로 일시에 수확하기 위해서는 기계파종에 의한 균일한 재배가 선행되어야 한다. 나. 시금치 수확요인시험 결과는 다음과 같다. (1) 절단날의 경사각이 0$^{\circ}$일 때 토양절단부하가 가장 적고 토양거동변화가 적어 시금치의 수확에 유리하였다. (2) 시금치 뿌리절단시험에서 뿌리절단날 종류별 뿌리절단부하는 산형 뿌리절단날의 내각이 작을수록 작았고, 일자날 일 때 크게 나타나는 경향을 보였으며, 일자날이 뿌리절단날의 토양절단 깊이에 대한 평균 뿌리절단길이가 가장 근접한 것으로 나타났다. (3) 뿌리가 절단된 시금치를 걷어올리는 시험에서는 주행속도 0.3m/sec, 체인컨베이어의 이송속도 0.5m/sec, 체인컨베이어의 이송각도 24$^{\circ}$, 지면에서 체인의 높이가 5cm 일 때 뿌리절단깊이 4cm 이하에서 시금치의 걷어올림 및 흙 분리가 양호한 것으로 나타났다. (중략)