RollUP: Rolling-Up End-Effector for Fabric Handling

The fabric deforms easily due to the physical constraints of its environment. The deformation of the fabric shape, including wrinkles, makes the precise pick-and-place of a piece of fabric difficult to automate its handling. This letter proposes a Rolling UP end-effector (RollUP) to pick-and-place a fabric piece while keeping it flat without making wrinkles. RollUP has a roller unit actuated by an electric motor and a vacuum suction slot on the roller. A fabric piece is picked up by air suction and rolled up. Rolling up the fabric reduces the unconstrained free area of the piece of fabric to be handled and makes it easier to handle a fabric with a large dimension. By attaching two RollUPs to the dual-arm manipulator, fabric tension can be controlled to keep it flat. Three experiments are conducted to evaluate the performance of RollUP. First, the grasping performance of the single RollUP for fabric pieces made of different materials and shapes is evaluated. Second, the relationship between the angle subtended by the fabric and the maximum force that can be applied to the fabric without slippage is investigated. Lastly, pick-and-place experiments involving a piece of fabric are performed using a dual manipulator system equipped with two RollUPs to evaluate performance.