Development of an autonomous tomato harvesting robot with rotational plucking gripper

In this paper, we present a design and development an autonomous tomato harvesting robot. We developed a harvesting robot with stereo camera which can measure depth in short range and direct sunlight and plucking gripper using the infinity rotational joint. We also evaluate the developed robot through harvesting in the tomato robot competition and the real farm. In the tomato robot competition, the robot harvested tometoes from tomato clusters and tomato trees, harvesting speed was about 80[s/fruit] and successful rate was about 60%. In the real farm we evaluated the robot with tomato trees in semi-outdoor environment to show the effectiveness and robustness under direct sunlight. According to the result of harvesting with real tomatoes, we improved the robot motion and finally harvesting speed was up to 23[s/fruit], however the gripper may grasp multiple fruits in case of very cluttered cluster and the calyx also may be broken when the stem angle is deep from the rotation axis. To avoid this situation, a grasp state estimation of the gripper and simultaneous recognition fruit and stem positions are next problems to improve the harvesting successful rate.