Design and Modeling of a Reconfigurable Robot: Decoupled STAR (DSTAR)
Tomer Siboni, Matan Coronel, David Zarrouk
AI summary
Problem
Miniature crawling robots often lack the maneuverability to traverse unstructured, rubble-filled environments or overcome large obstacles without relying on heavy, complex multi-motor systems.
Approach
The authors developed DSTAR, a reconfigurable robot that uses a single motor for symmetric sprawl and two independent motors for four-bar extension mechanisms, enabling precise center-of-mass shifts and adaptive locomotion gaits.
Key results
- 66% improvement in climbing capability over symmetric designs
- Sideways rolling to surmount 20 cm wall obstacles
- Stable omnidirectional navigation via a novel turtle gait
- Seamless switching between wheeled and wheg locomotion modes
Why it matters
This lightweight, mechanically simple design offers a highly adaptable solution for search-and-rescue and inspection tasks in confined, unstructured terrains where conventional robots and drones struggle.
Abstract
This paper presents Decoupled STAR (DSTAR), a novel reconfigurable robot fitted with a sprawling mechanism that allows the wheel rotation axes to vary relative to the body, and two independently activated four-bar extension mechanisms (FBEM). These mechanisms enable the robot to move its center of mass (COM) in any direction, and increase its maneuvering capabilities by selecting a variety of locomotion gaits. A kinematic model of the robot and a quasi-static force analysis are used to optimize the design and evaluate its motor requirements. Experiments demonstrate that combining the sprawling mechanism with FBEM enables the DSTAR to both crawl and drive, overcome a wide range of challenging obstacles, and improve its climbing capability by 66% compared to symmetric FBEM designs (such as RSTAR). The robot can crawl and maneuver over rough terrain using its unique turtle-gait method, roll sideways to surmount wall obstacles up to 20 cm high, travel horizontally across uneven ground, and switch between wheels and whegs to adapt to different terrain types, including dirt, stones, and grass. (see attached video).