Design of a magnetorheological robot gripper for handling of delicate food products with varying shapes

Natural food products are often variable in shape and easily bruised, making them difficult to handle for a robot. In this paper, a novel robot gripper that utilizes the effects of a magnetorheological (MR) fluid is described and evaluated. In the gripping process pouches filled with MR fluid are molded around the product’s contours. Through the activation of an electromagnet in the gripper arm, a large increase in the MR fluids yield stress confines the product in the mould produced by the gripper surfaces, allowing it to be lifted. Mounted on a six axis KUKA robot products such as apples, carrots, strawberries, broccolis and grapes have been handled without bruising or denting and without the tool changes that would typically be needed. The paper presents data regarding the forces exerted on products during gripping as well as data on maximum payloads and graspable product shapes.