Direct ink writing-printed silicone rubber and fused deposition modeling-fabricated PA6-CF for metamaterial-inspired hyper-redundant robotic manipulators

Abstract

Leveraging the high strength-to-weight ratio of composite materials for lightweight robot design, this study presents a cable-driven underactuated hyper-redundant robot with a metamaterial-inspired architecture, achieving performance in complex and constrained environments. By adopting a modular flexible structure, coupled with a soft-mechanism integration approach, we design a 10-joint hyper-redundant robotic arm composed of three modules: head, middle, and tail. The rigid arm is fabricated from carbon fiber–reinforced polyamide-6 using fused deposition modeling. Universal joints in the middle segment facilitate three-dimensional deflection, while single-axis joints in the head and tail segments provide axial motion stability. Underactuated cable coupling allows coordinated multi-degree-of-freedom motion with fewer drive units. Structural modularization and joint-level constraint design reduce volume and mass while improving spatial flexibility. The soft-tentacle mechanism, fabricated via direct ink writing (DIW), allows compliant deformation and adaptive grasping through pneumatic actuation. The experimental results show that the robot exhibits high flexibility and environmental adaptability during confined-space manipulation, with a maximum end-effector speed of approximately 90 mm/s, a positioning repeatability of less than 3 mm, and a maximum payload of about 300 g. Notably, this integrated design maintains motion stability comparable to fully actuated hyper-redundant robots, while reducing system complexity through underactuation and modular construction.

Keywords

additive manufacturing / 3D printing / carbon-fiber - reinforced polyamide-6 / underactuated hyper-redundant robots / hyper-redundant manipulation

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Central South University