Grasping and Rolling In-plane Manipulation Using Deployable Tape spring Appendages

Rigid multi-link robotic arms face a tradeoff between their overall reach distance (the workspace), and how compactly they can be collapsed (the storage volume). Increasing the workspace of a robot arm requires longer links, which adds weight to the system and requires a larger storage volume. However, the tradeoff between workspace and storage volume can be resolved by the use of deployable structures with high extensibility. In this work we introduce a bidirectional tape spring based structure that can be stored in a compact state and then extended to perform manipulation tasks, allowing for a large manipulation workspace and low storage volume. Bidirectional tape springs are demonstrated to have large buckling strength compared to single tape springs, while maintaining the ability to roll into a compact storage volume. Two tape spring structures are integrated into a bimanual manipulator robot called GRIP-tape that allows for object Grasping and Rolling In Planar configurations (GRIP). In demonstrations we show that the continuum kinematics of the tape springs enable novel manipulation capabilities such as simultaneous translation-rotation and multi-object conveyance. Furthermore, the dual mechanical properties of stiffness and softness in the tape springs enables inherent safety from unintended collisions within the workspace and soft-contact with objects. Our system demonstrates new opportunities for extensible manipulators that may benefit manipulation in remote environments such as space and the deep sea.