Now showing items 25-37 of 37

    • Noise, coherent fluctuations, and the onset of order in an oscillated granular fluid 

      Goldman, Daniel I.; Swift, J. B.; Swinney, Harry L. (Georgia Institute of TechnologyAmerican Physical Society, 2004-04-30)
      We study fluctuations in a vertically oscillated layer of grains below the critical acceleration for the onset of ordered standing waves. As onset is approached, transient disordered waves with a characteristic length scale ...
    • Persistent holes in a fluid 

      Merkt, Florian S.; Deegan, Robert D.; Goldman, Daniel I.; Rericha, Erin C.; Swinney, Harry L. (Georgia Institute of TechnologyAmerican Physical Society, 2004-05-07)
      We observe stable holes in a vertically oscillated 0.5 cm deep aqueous suspension of cornstarch. Holes appear only if a finite perturbation is applied to the layer for accelerations α above 10g. Holes are circular and ...
    • Phase bubbles and spatiotemporal chaos in granular patterns 

      Moon, Sung Joon; Shattuck, M. D.; Bizon, C.; Goldman, Daniel I.; Swift, J. B.; Swinney, Harry L. (Georgia Institute of TechnologyAmerican Physical Society, 2001-12-04)
      We use inelastic hard sphere molecular dynamics simulations and laboratory experiments to study patterns in vertically oscillated granular layers. The simulations and experiments reveal that phase bubbles spontaneously ...
    • The RiSE Climbing Robot: Body and Leg Design 

      Saunders, Aaron; Goldman, Daniel I.; Full, Robert J.; Buehler, Martin (Georgia Institute of TechnologySociety of Photo-optical Instrumentation Engineers (SPIE), 2006)
      The RiSE robot is a biologically inspired, six legged climbing robot, designed for general mobility in scansorial (vertical walls, horizontal ledges, ground level) environments. It exhibits ground reaction forces that are ...
    • Robotics in Scansorial Environments 

      Autumn, Kellar; Buehler, Martin; Cutkosky, Mark; Fearing, Ronald S.; Full, Robert J.; Goldman, Daniel I.; Groff, Richard; Provancher, William; Rizzi, Alfred E.; Saranli, Uluc; Saunders, Aaron; Koditschek, Daniel E. (Georgia Institute of TechnologySociety of Photo-optical Instrumentation Engineers (SPIE), 2005)
    • Scaling and Dynamics of Sphere and Disk Impact into Granular Media 

      Goldman, Daniel I.; Umbanhowar, Paul B. (Georgia Institute of TechnologyAmerican Physical Society, 2008-02-29)
      Direct measurements of the acceleration of spheres and disks impacting granular media reveal simple power law scalings along with complex dynamics which bear the signatures of both fluid and solid behavior. The penetration ...
    • Sensitive dependence of the motion of a legged robot on granular media 

      Li, Chen; Umbanhowar, Paul B.; Komsuoglu, Haldun; Koditschek, Daniel E.; Goldman, Daniel I. (Georgia Institute of TechnologyNational Academy of Sciences, 2009-03-03)
      Legged locomotion on flowing ground (e.g., granular media) is unlike locomotion on hard ground because feet experience both solid- and fluid-like forces during surface penetration. Recent bioinspired legged robots display ...
    • Signatures of glass formation in a fluidized bed of hard spheres 

      Goldman, Daniel I.; Swinney, Harry L. (Georgia Institute of TechnologyAmerican Physical Society, 2006-04-14)
      We demonstrate that a fluidized bed of hard spheres during defluidization displays properties associated with formation of a glass. The final state is rate dependent, and as this state is approached, the bed exhibits ...
    • Stationary state volume fluctuations in a granular medium 

      Schroeter, Matthias; Goldman, Daniel I.; Swinney, Harry L. (Georgia Institute of TechnologyAmerican Physical Society, 2005-03-30)
      A statistical description of static granular material requires ergodic sampling of the phase space spanned by the different configurations of the particles. We periodically fluidize a column of glass beads and find that ...
    • Systematic study of the performance of small robots on controlled laboratory substrates 

      Li, Chen; Hoover, Aaron M.; Birkmeyer, Paul; Umbanhowar, Paul B.; Fearing, Ronald S.; Goldman, Daniel I. (Georgia Institute of TechnologySociety of Photo-optical Instrumentation Engineers (SPIE), 2010-04)
      The design of robots able to locomote effectively over a diversity of terrain requires detailed ground interaction models; unfortunately such models are lacking due to the complicated response of real world substrates which ...
    • A terradynamics of legged locomotion on granular media 

      Li, Chen; Zhang, Tingnan; Goldman, Daniel I. (Georgia Institute of TechnologyAmerican Association for the Advancement of Science, 2013-03-22)
      The theories of aero- and hydrodynamics predict animal movement and device design in air and water through the computation of lift, drag, and thrust forces. Although models of terrestrial legged locomotion have focused on ...
    • Toward a dynamic climbing robot 

      Clark, Jonathan E.; Goldman, Daniel I.; Chen, Tao S.; Full, Robert J.; Koditschek, Daniel E. (Georgia Institute of Technology, 2006)
      Simple mathematical models or ‘templates’ of locomotion have been effective tools in understanding how animals move and have inspired and guided the design of robots that emulate those behaviors. This paper describes a ...
    • Walking and running on yielding and fluidizing ground 

      Qian, Feifei; Zhang, Tingnan; Li, Chen; Masarati, Pierangelo; Birkmeyer, Paul; Pullin, Andrew; Hoover, Aaron; Fearing, Ronald S.; Golman, Daniel I. (Georgia Institute of Technology, 2012-07)
      We study the detailed locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can move on a granular substrate of closely packed 3 mm diameter glass particles at speeds up to 50 cm/s (5 body ...