Motion analysis of the root-cutting blade for an automatic spinach harvester

In the present paper, motion analysis of a root-cutting blade which moves in soil of the spinach field of an automatic spinach harvester for eating raw is considered. The challenge is hard to develop the automatic spinach harvester because leaves and stems are soft and bruise easily, so that there are not any harvesters which are widely used in the farm. In contrast, the automatic spinach harvester under development by our research group shows the result of automatic harvesting for any types of spinach even if the farm field has no any ridge and interrow space in experimental test. In experiments using a test bed harvester, first, the root-cutting blade of the harvester moves in soil to cut the root of the spinach, second, the carrying part of the harvester consists of the conveyor belt collects the root cut spinach and carry them from the ground to the upper side. The trajectory of the root-cutting blade in soil is important for successful automatic harvesting, but any analysis have not been carried out for the investigation to find appropriate trajectory for harvesting. In the present paper, some characteristics are clarified using some numerical analysis of the root-cutting blade motion in soil and experimental results in the farm field. The numerical analyses of the motion of the root-cutting blade in soil are executed based on the discrete element method (DEM).