Recent studies of biological locomotion have highlighted the important role of lateral dynamics in achieving robust, high-speed locomotion. This has led to the development of reduced-order models for scansorial and terrestrial locomotion, which incorporate lateral force generation via a sprawled leg posture. Two such models are the Full-Goldman (FG) model for dynamic climbing and the Lateral Leg Spring (LLS) model for horizontal plane running. Though these models operate in different regimes, there are several parallels in the system dynamics and configurations, suggesting a natural compatibility to the incorporation of both into a single platform capable of utilizing both locomotion modalities. Although robotic platforms have been developed for the individual models, no robot has yet instantiated two dynamic locomotion models on the same platform.

While these models and platforms provide insight into the dynamics of biological locomotion, the simplication to bipedal configurations reduces their scope. Having only two limbs restricts control approaches that can be considered, limits navigable environments, complicates the maintenance of balance and stability, and precludes the utilization of leg differentiation. This last point is accentuated by studies of animals and other multi-legged robots that have demonstrated improved locomotion performance via the utilization of fore-aft leg specialization.