Meeting Abstract

S7-1.6  Friday, Jan. 6  Simple models for terrestrial locomotion and the materials that power it DUDEK, Dan; Virginia Tech dmdudek@vt.edu

It has long been known that a wide array of morphologically diverse terrestrial runners produce center of mass dynamics that are well modelled by a spring-loaded inverted pendulum (SLIP). This simple, general model has proven useful in generating and testing hypotheses regarding the passive dynamic stability, control, and energetics of running on the level. Similarly, despite differences in attachment mechanism, foot morphology, and leg number, geckos and cockroaches produce a common dynamic pattern while rapidly climbing. In the frontal plane, the center of mass (COM) cyclically accelerates up the wall in synchrony with cyclical side-to-side motion that results from alternating net lateral pulling forces. Modeling these dynamics requires only a rigid body and a linearly actuated spring. As with the SLIP model, using these dynamics as a target for biologically inspired legged robots has proven successful. Broad generalities can also be found in the materials and structures used by these diverse animals during running. For example, despite being composed of different materials with varying morphologies, many structures loaded during locomotion demonstrate frequency independent material properties. Combining simple frequency independent models of the materials with the models for the dynamics of the COM may lead to an integrative understanding of terrestrial locomotion from the molecular to the organismal level.