• Agricultural and Biosystems Engineering
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• v.2 no.2
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• pp.69-74
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• 2001

Detection of operation lines in farm works, object recognition and obstacle avoidance are essential pre-requisite technologies for unmanned agricultural machinery. A CCD camera, which has been largely used for these functions, is expensive and has difficulty in real-time signal processing. In this study, a laser range sensor was selected as the guiding vision for unmanned agricultural machinery such as a tractor. To achieve this capability, algorithms for distance measurement, signal filtering, object recognition, and obstacle avoidance were developed. Computer simulations were carried out to evaluate performance of the algorithms. Experiments were also conducted with various materials and shapes, Laser beam lost its intensity for poor reflective materials, resulting in less range value than actual, so a compensation technique was considered to be necessary. Object detection system was fabricated on an agricultural tractor and the performance was evaluated. As test result for obstacle detection and avoidance in field, to detect and avoid obstacle for path finding with guiding system for unmanned agricultural machinery was enable.

• Journal of Biosystems Engineering
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• v.31 no.2 s.115
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• pp.95-101
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• 2006

Present chemical application system using a power sprayer has been a labor intensive, ineffective and shirking task in farming. Therefore, a small RF controlled (unmanned) helicopter was suggested to replace the conventional spray system. The aerial application using the unmanned helicopter has been already utilized in Japan, where total area applied up to 704,000 ha in 2005. In this article, the status and cost analysis on the unmanned agricultural helicopter were studied. The aerial application using the agricultural helicopter helps precise and timely spraying and reduces labor intensity and pollution. The field capacity of the helicopter was found to be 60-70 ha a day. The break even point was estimated near the operating area of 750 ha annum. The development of an agricultural helicopter was necessary for taking advantages of both technique and economy.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.165-173
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• 2020

The emergence of unmanned agricultural machinery has brought new research content to the development of precision agriculture. In order to speed up the research on key technologies of unmanned agricultural machinery, classification of intelligence level of unmanned agricultural machinery has become a primary task. In this study, the researchers take the complex interactive system consisting of unmanned grain harvester, task and driving environment as the research object, and carry out a research on the grading and classification of intelligent level of unmanned grain harvester. The researchers of this study also establish an evaluation model of unmanned grain harvester vehicle, which consists of human intervention degree, environmental complexity, and task complexity. Besides, the grading and classification of intelligence level of the unmanned grain harvester is carried out according to the human intervention degree, environmental complexity and the task complexity of the unmanned grain harvester. It provides a direction for the future development of unmanned agricultural machinery.

• Journal of Biosystems Engineering
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• v.33 no.2
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• pp.94-100
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• 2008

Present chemical application method using a power sprayer has been labor intensive, costly and ineffective. Therefore, a small agricultural unmanned helicopter was suggested to replace the conventional spray system. In this study, conceptual design for developing the helicopter and a consequential prototype were reported. The overall conceptual design was initiated by deciding the type of agricultural helicopter, as the single rotor helicopter with a tail system. As the first step of the designing, an air-cooled, 2-stroke engine was selected and a prototype transmission was designed by determining the rotating speed of main rotor shaft. A 'pusher' type tail rotor system was adapted to balance the reaction torque and reduce the power use. The tail boom length was designed to avoid the rotating trajectory of the main rotor. The RF console consisted of the engine control, attitude control, and emergency control modules. Assembling the prototype concluded the mechanical development of the agricultural helicopter.

• Journal of Biosystems Engineering
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• v.35 no.5
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• pp.302-309
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• 2010

Aerial application using an unmanned agricultural helicopter would allow precise and timely spraying. The attitude of a helicopter depends on a number of dynamic variables for roll-balanced flight. Laterally tilting behavior of a helicopter is a physically intrinsic phenomenon while hovering and forwarding. In order to balance the fuselage, the rotor should be counter-tilted, resulting in the biased down-wash. The biased spraying toward right side causes uneven spray pattern. In this study, a raised tail rotor system for the roll-balanced helicopter was studied. Thrust of the tail rotor system was measured and theoretically estimated for the fundamental database of the roll-balanced helicopter design. The estimated tail thrust and roll-moment would be used to design the raising height of tail rotor and roll balancing dynamics. The unmanned agricultural helicopter required the tail rotor thrust of about 39.2 N (4.0 kgf) during hovering with a payload of 235.4 N (24 kgf). A raised tail rotor system would compensate for the physical tilt phenomena. A further attitude control system of helicopter would assist roll-balanced aerial spray application.

• Journal of Biosystems Engineering
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• v.31 no.3 s.116
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• pp.182-187
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• 2006

Aerial application using an unmanned agricultural helicopter can reduce labor and pollution. The development of an agricultural helicopter became urgent for both precise and timely spraying. In this study, a rotor system for unmanned helicopter capable of 20 $kg_f$ payload, was developed and lift capability was evaluated. A lift force over the dead weight of the helicopter was obtained at the pitch angle of $6^{\circ}$. As the pitch angle increased to $8^{\circ}\;and\;10^{\circ}$, the total lift increased to $74{\sim}81\;kg_f\;and\;86{\sim}93\;kg_f$, respectively. A range of engine speed at the rated flight condition, lifting mean payload of 23 $kg_f$ was determined. The data acquired from this study will be used for designing tail system and RF console in the next stage of the research. The rated lift capability was enough for loading 20 liters of spray material including spraying equipments.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1264-1272
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• 1993

The software for unmanned control of three row typed rice combine has been developed using fuzzy logic. Three fuzzy variables were used : operating status of combine, steering, and speed. Eleven fuzzy rules were constructed and the eleven linguistic variables were used for the fuzzy rules. Six sensors were use of to get input values and sensor input values were quantified into 11 levels. The fuzzy output was infered with fuzzy inferrence which uses the correlation product encoding , and it must have been defuzzified by the method of center of gravity to use it for the control. The result of performance test using graphic simulation showed that the intelligently unmanned control of a rice combine was possible using fuzzy logic control.

• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.14-20
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• 2008

An agricultural unmanned helicopter was suggested for an alternative to current pesticide application methods to solve such problems as high cost, low efficiency, shirking task and unsafe work. To pursuit this trend, researches on the development of unmanned helicopters have been accelerated in Korea as well. In this research, a guide type centrifugal clutch that plays an important role in the unmanned helicopter was studied. Theoretical analyses and experimental tests were conducted for designing an optimal clutches. Main design factors of the guide type centrifugal clutch were found to be spring constant, free length of spring, mass of friction sector, contact area, allowable pressure, number of friction sector, friction coefficient, radius of drum, and clutch arrangement. And these design factors could be the functions of engaging engine speed and desired power transfer capacity. The result of the single clutch test showed the power transfer capacity of 14.1 PS at 5,800 rpm and the result of the dual clutch test showed that the capacity of 17.7 PS at 5,600 rpm. These experimental results agreed well the theoretical simulations.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.23-29
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• 1999

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1997.12a
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• pp.11-17
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• 1997