Design of Knitted Superelastic Tire Treads for Next Generation Non-Pneumatic Rover Tires

Terrestrial rover vehicles require tires that can withstand harsh environments while still being optimized for traction in different conditions. Past rover tires have suffered from failure due to fatigue, jagged rocks, and uneven weight distribution, shortening the operational lifespan of the vehicle and limiting research capabilities. The recent development of the superelastic spring tire shows significant improvement by leveraging material strains and geometric deformations to increase recoverable structural deformations. However, the interlocking spring architecture is limited to a single surface topology that may not be ideal for all terrain or all tire designs. This research presents superelastic knitted structures useful for a rugged tire skin because they support large forces, recover large deformations, and provide a variety of surface topologies. In this study, a prototype superelastic knitted tire is built to the form factor of a moped and experimentally tested. The tire’s stiffness, traction properties, resilience, and scalability are investigated and compared to NiTi and rubber tire performance in rugged environments. A variety of surface topologies are manufactured through the implementation of different knitted patterns and compared to traditional grouser element geometries. The ability to tune the mechanical performance through the choice of geometric parameters and knitted pattern is discussed. Knitted superelastic tire treads provide vast design customization through a scalable manufacturing process, potentially enabling next-generation compliant rover tires with enhanced longevity, reusability and increased explorable terrain.