Force control approach for the automation of cashew-shelling operation

Vietnam is one of the world´s largest countries in terms of exportingers of cashews nuts in kernel (edible portion) form. Currently, more than 200,000 labors are engaged in the cashew processing industry. Although most cashew processing operations have been automated, the shelling operation is still conducted manually. Consequently, the shelling rate is very low compared to other operations, and the labor conditions are strenuous and unsafe. This paper introduces a cashew-shelling machine design to improve the production efficiency and working conditions. The proposed design includes shell milling operation and wedge splitting process designs. In addition, a conveyor system design to transport cashews is included to increase the production efficiency. Because cashews come in different sizes, we propose a force controller for the milling system that cuts the cashew shell without deteriorating the cashew kernel. Experimental results demonstrate the effectiveness of the proposed force controller.