Developing and Evaluating a Mechanical Leaf Removal Design for a New Broccoli Variety

Abstract

Automation within an industrial sector has now for years been an obvious factor. Everywhere mechanical instruments and sensors are implemented for fast and precise processes. The agricultural sector is some steps behind in relation to other sectors. Reason being that there are many irregularities which in other sectors have been made into uniform variables. One of the problems that needs to be tackled within the agricultural sector is having the leaves of crops removed.
Rijk Zwaan has created a new variety of broccoli and to make this commercially viable, a harvest machine is required. One of the aspects of this harvesting process is removing the leaves. This has to be achieved in one continuous session, with at least a ground speed of 1 km/h, while the broccoli's are still in the field. With a focus on the best performance for the least destructive working principle. After listing all the requirements, ideas are structured in a morphological overview. A weighted criteria table will be used to select three ideas, which will be made into prototypes.
Results from the initial testing period will reveal the best concept, which will be optimised. This was the Metal Wire design, which exist of multiple stainless steel wires attached perpendicular to a rotating shaft. An important aspect that boosted the performance was the unravelled ends of these wires. These rotating shaft had the wires removing the leaves, while beating the leaves down from both sides.
After optimization, the current prototype could ensure a 60% of the top section and 80% of the middle section with 20% of the broccoli’s destroyed. Which was not enough to satisfy the goal, however the promising results could be improved with an upgraded machine. A clear trade-off was found between the performance and destruction. Significant improvements in results could be achieved by incorporating additional features such as a funnel and designing a more robust structure with fewer obstructions, controllable ground/rotational speed, and better alignment with the beds. Therefore at the current state the leaf removal machine operates substandard, but has potential to be developed into the desired product.