Development and Evaluation of a Tomato Fruit Suction Cutting Device

Abstract

This paper introduces a structure and harvesting motion for the suction cutting device of a tomato harvesting robot, and reports harvesting experiments conducted in a tomato greenhouse. The suction cutting device comprises a suction part and a cutting part. The suction part separates the target fruit from a tomato cluster and the cutting part cuts the peduncle of the target fruit. A photoresistor in the cutting part assesses whether or not the target fruit is harvestable, and the cutting motion is performed only when the fruit is assessed as harvestable. The harvesting experiments were conducted in a tomato greenhouse to evaluate the suction cutting device. In this experiments, 50 tomato clusters were randomly selected as the harvesting objects, and there were 203 tomato fruits (including immature fruits). Out of the 203 tomato fruits, 114 tomato fruits were mature and within the robot workspace. Out of the 114 tomato fruits, 105 tomato fruits were recognized as target fruits by the harvesting robot. Out of these 105 tomato fruits, 65 tomato fruits were assessed as harvestable and 55 were successfully harvested (the harvesting success rate was 85%). Based on the results of the harvesting experiments, this study clarified the issues of the suction cutting device, classified the fruits according to whether they were easy or difficult to harvest, and evaluated the fruit characteristics qualitatively.