ISHS Acta Horticulturae 440: International Symposium on Plant Production in Closed Ecosystems
DEVELOPMENT OF A GRIPPER FOR A PLUG-IN GRAFTING ROBOT SYSTEM |
| Authors: | Y. Nishiura, H. Murase, N. Honami, T. Taira, A. Wadano |
| Keywords: | compression test, grafting robot, gripper development, handling, physical property, shearing test, slippage test |
| Abstract:
A gripper for a fully automatic grafting robot that uses the "Plug-in Method" was developed. Since the gripper is an important handling mechanism of the robot, its design requires special considerations. When the seedlings are transported, the gripper moves downward by its own weight. When shaping the end of the scion and stock for the Plug-in Method, the gripper exerts rotational forces. The gripper also exerts static forces when it firmly holds a seedling. Longitudinal shearing and rotational forces occur when the seedling is picked from the plug-cell tray, cut, tapered and drilled to make a conical hole. Tomato seedlings with different physical properties were used for the determination of the gripper design parameters. The seedlings were subjected to both compression and shearing tests. The critical values of elastic and shear forces were found to be 120 and 300 gf/mm of stem diameter, respectively. A prototype gripper was fabricated and tested for tension and shear. When forces applied to the gripper exceeded 150 gf/mm diameter, the gripper crushed the seedlings. It was found that when a maximum grip force of 150 gf/mm diameter was applied to the gripper, a force of 100 gf/mm diameter was required to slip the seedlings in the gripper. The gripper was tested for its effectiveness in holding the scion and stock when being shaped for grafting. It was found that with 150 gf/mm diameter grip force, a force of 50 gf/mm diameter was required to slip the seedlings during rotation. | |
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