Journal
NATURE PHYSICS
Volume 12, Issue 3, Pages 278-+Publisher
NATURE PUBLISHING GROUP
DOI: 10.1038/NPHYS3568
Keywords
-
Categories
Funding
- NSF Physics of Living Systems
- Burroughs Wellcome Fund
- Army Research Office
- Division Of Computer and Network Systems
- Direct For Computer & Info Scie & Enginr [1544857] Funding Source: National Science Foundation
Ask authors/readers for more resources
Characterizing forces on deformable objects intruding into sand and soil requires understanding the solid- and fluid-like responses of such substrates and their effect on the state of the object. The most detailed studies of intrusion in dry granular media have revealed that interactions of fixed-shape objects during free impact (for example, cannonballs) and forced slow penetration can be described by hydrostatic- and hydrodynamic-like forces. Here we investigate a new class of granular interactions: rapid intrusions by objects that change shape (self-deform) through passive and active means. Systematic studies of a simple spring-mass robot jumping on dry granular media reveal that jumping performance is explained by an interplay of nonlinear frictional and hydrodynamic drag as well as induced added mass (unaccounted by traditional intrusion models) characterized by a rapidly solidified region of grains accelerated by the foot. A model incorporating these dynamics reveals that added mass degrades the performance of certain self-deformations owing to a shift in optimal timing during push-off. Our systematic robophysical experiment reveals both new soft-matter physics and principles for robotic self-deformation and control, which together provide principles of movement in deformable terrestrial environments.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available