Abstract
Tomato harvesting robots have been reported in recent years in Japan. In the reports, two plate hand, hand with three fingers which are driven by air pressure, and hand which harvests by rotating part with guide bar have been studied. But the physical properties of each part of tomato plant have not been considered enough when they were manufactured, therefore the hands could not harvest fruit and injured other fruits in the same cluster or stems sometimes.
In this paper, a harvesting method to pick fruit up at joint after dividing objective fruit from others was contrived in order to develop hand which was able to harvest with no damage not only to the fruits but also to tomato plant. Before manufacturing the harvesting hand, fruit moving distance in cluster, picking force and picking angle at joint were studied. Two finger hand with absorptive pad was made as a trial based on the physical properties. Besides, harvesting experiment was done, after the hand was attached to manipulator with 7 degrees of freedom. From the results, the following was obtained.
1) Fruit moving distance in cluster was 50 mm in average.
2) It was adequate to pick fruit up on YZplane or on ZX plane from the results of picking force and picking angle at joint.
3) The hand was able to harvest fruit in cluster successfully with no damage.
4) The hand would be improved, if sensors which detected pressure and position of the pad were attached to it.
