Bio-Inspired Rolling-Disk Continuum Robot: Logarithmic Spiral and Constant Curvature Design with Contraction Capabilities
Md Modassir Firdaus, Vikranth Mallru, Harsh Malodia, Madhu Vadali
Abstract
Soft robotics draws inspiration from biological appendages like seahorse tails, octopus arms, and elephant trunks, which demonstrate remarkable flexibility and diverse functionalities. While advances in soft robotics have enabled delicate manipulation, safe human interaction, and medical applications, existing systems lag behind mimicking nature with a change in length. This paper presents a novel rolling-disk-based continuum robot design that replicates natural logarithmic spiral geometry while overcoming limitations of previous bio-inspired systems, including fixed length, complex elastic interconnects, and absent central lumens. The proposed 3D-printable architecture enables cost-effective rapid prototyping with adjustable parameters, achieving both logarithmic spiral and constant curvature bending, consistent with established kinematic models. A central hollow passage supports tool integration for minimally invasive procedures, while contraction capability enables dynamic length adjustment. Comprehensive mathematical analysis, CAD development, and SOFA simulations validate the design conceptualisation. Experimental demonstrations confirm bending, contraction, and grasping capabilities across diverse object geometries, establishing a foundation for scalable, adaptable tendon-driven continuum robots that bridge biological inspiration with practical engineering implementation.