When Rolling Gets Weird: A Curved-Link Tensegrity Robot for Non-Intuitive Behavior
Lauren Ervin, Harish Bezawada, Vishesh Vikas
AI summary
Problem
Traditional straight-link tensegrity robots suffer from slow locomotion due to complex actuator coordination, while spherical robots lack the stability needed for unstructured terrain navigation.
Approach
The authors developed TeXploR2, a semi-circular curved-link robot that uses internal shifting masses to dynamically change ground contact points, enabling smooth rolling and stability validated through geometric modeling and experiments.
Key results
- Prototype achieves 0.71 body lengths per second, nearly triple the speed of straight-link designs
- Quasistatic simulation maps piecewise continuous rolling across four distinct locomotion states
- Experimental validation confirms successful dynamic rolling and non-intuitive state transitions
- Impact testing demonstrates structural shock absorption that preserves locomotion continuity
Why it matters
Provides a scalable, compliant robotic platform optimized for efficient and stable exploration in unstructured environments like lunar regolith and disaster zones.
Abstract
Conventional mobile tensegrity robots constructed with straight links offer mobility at the cost of locomotion speed. While spherical robots provide highly effective rolling behavior, they often lack the stability required for navigating unstruc- tured terrain common in many space exploration environments. This research presents a solution with a semi-circular, curved- link tensegrity robot that strikes a balance between efficient rolling locomotion and controlled stability, enabled by disconti- nuities present at the arc endpoints. Building upon an existing geometric static modeling framework [1], this work presents the system design of an improved Tensegrity eXploratory Robot 2 (TeXploR2). Internal shifting masses instantaneously roll along each curved-link, dynamically altering the two points of contact with the ground plane. Simulations of quasistatic, piecewise continuous locomotion sequences reveal new insights into the positional displacement between inertial and body frames. Non- intuitive rolling behaviors are identified and experimentally validated using a tetherless prototype, demonstrating successful dynamic locomotion. A preliminary impact test highlights the tensegrity structure’s inherent shock absorption capabilities and conformability. Future work will focus on finalizing a dynamic model that is experimentally validated with extended testing in real-world environments as well as further refinement of the prototype to incorporate additional curved-links and subsequent ground contact points for increased controllability.