Characterising 3D-printed Soft Fin Ray Robotic Fingers with Layer Jamming Capability for Delicate Grasping

Abstract

Motivated by the growing need within the agri-food industry to automate the handling of delicate produce, this paper presents soft robotic fingers utilising the Fin Ray <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> effect to passively and gently adapt to delicate targets. The proposed Soft Fin Ray fingers feature thin ribs and are entirely 3D printed from a flexible material (NinjaFlex) to enhance their shape adaptation, compared to the original Fin Ray fingers. To overcome their reduced force generation, the effects of the angle and spacing of the flexible ribs were experimentally characterised. The results showed that at large displacements, layer jamming between tilted flexible ribs can significantly enhance the force generation, while minimal contact forces can be still maintained at small displacements for delicate grasping.