A Wrapping Gripper for Packaging Chopped and Granular Food Materials

Abstract

Pneumatic driven soft robotic gripper has been studied intensively in recent years for grasping various types of objects including food materials. However, grasping of finely chopped and granular food materials has not been investigated frequently. This paper presents a pneumatic soft gripper capable of forming an approximately closed cavity to wrap the chapped and granular food materials. The gripper consists of four soft fingers and each finger was constructed by multiple horizontal and vertical air chambers. When the chambers were inflated, the finger bends towards two perpendicular directions. Finite element (FE) model of the soft finger was developed to predict the desired deformation behaviors. A robotic gripper was assembled with four soft fingers in a circular configuration. Experimental tests were conducted on grasping granular kernel corn, chopped green onion, and boiled hijiki. Results showed that the proposed gripper is able to wrap the food materials and the averaged weight of the grasped materials can be controlled by varying the insertion depth. However, the variations in grasped weight among trials are relatively large.