A gripper for delicate edible manipulation

The general manipulation of delicate edible products requires of specific grippers able to firmly grasp these kind of products without damaging them. To address this problem we follow a soft and variable-stiffness approach. In this paper we design and construct successive gripper prototypes which fingers are composed of rigid and soft parts. The stiffness of the soft parts can be modified using the jamming principle. The gripper properties are experimentally evaluated using a subset of NIST benchmarks. This allows to obtain comparable and standardised results, used to improve the initial gripper design. In addition a new benchmark, the edible grasping benchmark, is proposed and used to measure the performance of the grippers while grasping fruits and vegetables. The final gripper prototype overcomes the problems observed in fruit and vegetable picking systems. It has been demonstrated in the experimental tests that the gripper has sufficient payload and adaptability to grasp several edibles without damage.