内成り栽培用イチゴ収穫ロボット(第2報) : 2号機の試作と収穫基礎実験 [in Japanese] Harvesting Robot for Strawberry Growth on Annual Hill Top (Part 2) : Manufacture of the second Prototype Robot and Fundamental Harvesting Experiment [in Japanese]
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内成り栽培されたイチゴをロボット収穫することを目的とし, 1号機の問題点を解決するため, 2号機を試作し, 収穫実験を行った.その結果, 以下の知見が得られた.<BR>1) 1号機に見られた4つの問題点は解決され, 対象とした成熟果12個はすべて損傷なく収穫可能であった.<BR>2) 本実験で用いた視覚センサのアルゴリズムは, 成熟果を識別し, 位置検出するために有効で, 目的果実の近隣にある果実を誤って収穫した場合にも対処可能であること, 実際に計測したZ座標の平均値を用いることで, 正確に果実の三次元位置が計測可能であること, 収穫時に位置が移動した果実にも対処可能であること等の利点があった.<BR>3) 本エンドエフェクタの問題点として, 未熟果を成熟果と同時に吸い込むことがあること, エンドエフェクタの接地位置を判断する必要があること, 開閉部が他の果実に接触することがあることがあげられた.
The second prototype robot for harvesting strawberries grown on annual hill top was made for trial based on experimental results of the first prototype robot. Its manipulator was a cartesian coordinate type with three degrees of freedom and a sucking type end-effector was attached to the manipulator. Harvesting action of the robot was as follows : The end-effector moved downward until the sucking head reached ground. It was possible to stop end-effector movement without measuring the depth to ground by an external sensor because a limit switch was attached to sucking head of the end-effector. The end-effector could suck a target fruit into the sucking head. When two pairs of photo-interrupters detected the fruit in the sucking head, the manipulator moved upward and internal cylinder rotated to cut peduncle. Even if the peduncle was not cut by the rotation, an open-close section was closed and detached the fruit from the peduncle. As the visual sensor, a color CCD camera was used. Three dimensional positions of target fruits were calculated from a two dimensional image acquired by the camera and from the depth when the end-effector reached ground. The depth was stored and ac-cumulated in computer memory and the averaged value was used as z coordinate of the next target fruit.<BR>From the experimental results, it was observed that every mature fruit could be harvested in about 7 seconds. Although the success rate was 100%, some adjacent immature fruits were sucked with the target fruits. It was considered that control of volume flow rate of the vacuum device and immature fruit position detection were necessary from engineering view point and that control of peduncle length was desired from horticultural view point in order to reduce the sucked immature fruits.
- Shokubutsu Kojo Gakkaishi
Shokubutsu Kojo Gakkaishi 13(4), 231-236, 2001-12-01
JAPANESE SOCIETY OF AGRICULTURAL, BIOLOGICAL AND ENVIRONMENTAL ENGINEERS AND SCIENTISTS