Numerical Investigation of a Granular-based Gripper

  • Dierks, Niklas (Institut für Partikeltechnik)
  • Wacker, Christian (Institut für Werkzeugmaschinen und Fertigungs)
  • Zetzener, Harald (Institut für Partikeltechnik)
  • Schilde, Carsten (Institut für Partikeltechnik)
  • Dröder, Klaus (Institut für Werkzeugmaschinen und Fertigungs)
  • Kwade, Arno (Institut für Partikeltechnik)

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A sub-discipline of material flow in production systems is handling, involving the positioning and movement of objects such as materials and products. Therefore, handling systems, consisting of a movement device (robots), end effector (gripper), sensors, peripherals and a grasping object, are used. For successful grasping of an object, the design of the gripper and the understanding of the influences of process and design conditions are crucial. This contribution investigates a new type of gripper, shown in Figure 1. It is granular-based and consists of a flexible membrane filled with granules and a porous surface on the underside. This design enables the gripper to adapt to different shaped objects for secure grasping and handling. By varying the level of granule filling and the properties of the granules and membrane, the degree of formability and possibilities of a molding to the surface of grasped objects can be influenced. When a vacuum is applied, the suction force allows for a secure grasp of different geometries. Preliminary experimental studies have proven that an improved shape-adaption influences the resulting achievable gripping forces positively and thus leads to a more secure grasp. In order to enable further insights into the influences of the gripper design and the process conditions on the gripping process, the molding process is investigated numerically with DEM. For this purpose, the influences of the bond properties forming the airtight membrane, the particle properties such as friction, Young's modulus and coefficient of restitution as well as the process parameters on the resulting molding of the gripper on the gripped object are investigated. Finally, a comparison with the experimental results will assess, whether a prediction of the grasping force based on the moulding process is already possible or a CFD/ CFD-DEM simulation is necessary.