A problem associated with the aging society in Japan is that the number of people working in the field of agriculture is decreasing. This is also the case for strawberry farmers. However, the idea of applying robotics technology in farming has been introduced, and some strawberry farms are now preparing to use this technology since elevated cultivation has become popular recently. Our goal is therefore to develop a strawberry-harvesting robot system.

* This research is supported by the Bio-oriented Technology Research Advancement Institution. This research is also a collaboration between Waseda University and Maekawa Manufacturing Company.

The requirements for a strawberry-harvesting robot system are as follows:

1. Able to harvest without harming the soft strawberry fruit
2. Able to achieve a high crop yield

Automatic harvesting at night

This automatic harvesting system consists of rail tracks placed under elevated strawberry beds in the strawberry greenhouse and a robotic manipulator that runs along the tracks picking the fruit whose position it recognizes with stereo cameras. This harvesting is done at night because the camera recognition is stable when there is no sunshine.

Approaching from beneath the elevated soil bed

By observing the strawberry fields, we found that mature, red fruit tends to hang strait down from the soil bed, so the ripe berries in the fruit clusters may hang lower than the unripe ones. Because of this characteristic, approaching the fruit from beneath the soil bed is very effective because the mature fruit is usually facing away from the soil bed.

Symmetrical system on the soil bed line

This system is designed to be symmetrical on the soil bed line so that the manipulator can approach both sides of the fruit. To achieve the camera recognition on both sides, the robot is equipped with two sets of stereo cameras. This recognition system can shorten the work-time of the harvesting process because one set of stereo cameras can capture the fruit while the manipulator is approaching on the other side.

End effector that clips the strawberry stems

The end effector installed on the manipulator can clip the strawberry stem so that the harvesting process does not harm the soft strawberry fruit.