Multi-Fingered Soft Gripper Driven by Bellows Actuator for Handling Food Materials

In Japan, the demands for automation in the food industry are constantly increasing in recent years due to the labor shortage caused by the super-aged society. However, robotic handling of raw food materials presents challenges for conventional rigid grippers due to the large variations in shape, size, fragility, and surface properties of food materials. In this paper, soft grippers driven by bellows actuator are proposed for handling various food products. The idea is to use the contraction of the bellows actuator to drive a multi-fingered soft structure for grasping. An important feature of the proposed grippers is that they actively make contact with the environment during grasping, and therefore, they are expected to be able to grasp food materials with thin profiles. Three different gripper designs, which have two, six, and eight fingers respectively, were fabricated and experimentally tested for grasping five kinds of raw food products. We found that the proposed grippers can grasp thin food products such as a Japanese omelet. Results also suggested that increasing the number of the fingers did not guarantee better grasping performances and the parallel two-fingered gripper performed the best among the three different gripper designs.