Enhancing performance in Flexible Mono-Tread Mobile-Track (FMT) through smooth flexion and passive mechanism: Designing the vertebral structure and head shape

Abstract

We have developed a Flexible Mono-tread Mobile-Track (FMT), which exhibits an inherent capability for flexed posture in three dimensions and can traverse over rough terrain, particularly in post-disaster scenarios. The flexion mechanism of the FMT passively adapts to irregular ground surfaces, reducing overall weight, degrees of freedom for operation, and the operator's workload. Rigorous testing of legacy prototypes confirmed the remarkable mobility, following the National Institute of Standards and Technology (NIST) guidelines. The FMT’s performance is notably influenced by the flexibility of the vertebral body structure and the shape of the track belt. For instance, the asymmetric track belt results in anisotropy of forward and backward movement, while the layered body cannot achieve uniform three-dimensional flexion. Additionally, the asymmetric or simple circular head shape poses challenges in ensuring consistent climbability over steps with overhang walls. This paper proposes a solution involving a new vertebral body structure and symmetric track belt for the FMT. The resulting prototype, MRT03-GEJIY, addresses these challenges and improves upon the performance of the legacy FMT prototypes in the following: 1) Establishing a reliable vertebra for achieving wide and uniform curvature, facilitating smooth track belt movement. 2) Implementing a symmetric track segment to enhance the isotropy in forward and backward movement. 3) Introducing a horizontally symmetrical head shape equipped with passive obstacle-crossing capability. Furthermore, we conducted performance evaluations of MRT03-GEJIY, including tests such as step-climbing.

Keywords

• tracked robot
• flexible mono-tread mobile track
• mobile mechanism
• track belt
• vertebral structure