A hygienically designed force gripper for flexible handling of variable and easily damaged natural food products

To overcome present difficulties in robotized food handling a force sensing robot gripper for flexible production is presented. A magnetic coupling is used to completely encapsulate the actuator mechanism, improving hygiene and enabling a future hose-down proof design. Product location, orientation and product type and width are extracted by a vision system to aid the gripping process. Knowing the product type the grip force is set individually for each product. In the paper data of achievable grip strength, positioning accuracy and gripping times for force controlled gripping are presented. Grip times of 410-530 ms for grip forces of 50-700 g respectively are realized. An initial microbiology study on a model system showed that an intermediate decontamination can be used to reduce the cross contamination of Listeria innocua (SIK215) significantly. The gripper is further shown to be able to handle an in-feed mixture of tomatoes, apples, carrots, broccoli and grapes without intermediate adjustments. Industrial relevance: This paper covers the development and evaluation of a hygienically designed universal robot food gripper. The gripper enables an increased use of robots in the food industry and makes very flexible production with minimal changeover times possible. (C) 2011 Elsevier Ltd. All rights reserved.