Daniel Goldman, an Assistant Professor in the Georgia Tech School of Physics, has been named a recipient of a 2012 DARPA Young Faculty Award for his proposal "Towards a terramechanics of heterogeneous granular media". The DARPA Young Faculty Award program identifies and engages rising research stars in junior faculty positions at U.S. academic institutions and exposes them to Department of Defense needs as well as DARPA’s program development process.
Dr. Goldman’s research addresses problems in nonequilibrium systems that involve interaction of physical and biological matter with complex materials (like granular media) that can flow when stressed. Researchers in Dr. Goldman’s Complex Rheology and Biomechanics Lab (CRAB Lab) integrate laboratory and field studies of organism biomechanics with systematic laboratory studies of physics of the substrates, create models of the substrates, and create mathematical and physical (robot) models of the organisms.
Terramechanics began as the application of the continuum theory of soil mechanics to the ground intrusion and slip of wheeled and tracked vehicles. A major challenge to creating the next generation of mobile robots is expanding the scope of terramechanics from large tracked and treaded vehicles on homogeneous ground to arbitrarily shaped and actuated locomotors moving on and in complex heterogeneous terrestrial surfaces (substrates). An enhanced terramechanics encompassing complex substrates will allow rapid simulation of the realistic movement of small robots traveling across rocky, loose, terrain with multi-scaled structure and the ability to flow when sheared. The design and performance advantages associated with improved substrate modeling will enhance prediction of trafficability, power consumption, failure (due to slip, unpredictable foot-holds, or impassable barriers) without the need to perform extensive field-testing, experimentation and other cut-and-try approaches.
Goldman's interests in advancing terramechanics originate in the scientific and practical challenges robotic and biological locomotors face when confronted by heterogeneous granular terrain like washes found in deserts. How should fluctuations in substrate flow and reaction force be modeled? Answering this questions entails understanding the importance of relative size (grain/grain and grain/locomotor) and the spatial distribution of material (structure) and its evolution under local forcing by the locomotor. To address heterogeneity induced fluctuations, Goldman will create a laboratory approach in which he develops test beds and an experimentally validated modeling framework for the interaction of legged, wheeled, tracked and limbless (undulatory) vehicles of small to medium scale with heterogeneous unconsolidated granular terrain. The work will build on experimental, computational and theoretical tools developed in his laboratory for the study of animal and robot locomotion on mono-disperse GM.