Kevin P. Granata Memorial Lecture

Wednesday, April 29, 2009
4:00 - 5:00 PM
190 Holden Auditorium

Dr. Andrew Biewener
Department of Organismic and Evolutionary Biology, Harvard University

A multi-level approach is needed to understand how the in vivo function of muscle-tendon units, operating at specific joints within the limb, is integrated with limb and whole-body dynamics. Rapid adjustments to destabilizing perturbations are likely facilitated by intrinsic force-velocity and force-length properties of the muscle and tendon, prior to neural feedback. Differences in muscle-tendon architecture suggest that a proximo-distal gradient of muscle function and neuromotor control may operate within the limbs of vertebrate animals: with proximal muscles hypothesized to modulate work output and operate under feedforward control versus distal muscles that perform little work and respond to rapid intrinsic feedback control. Simple mass-spring mechanics describe well the mechanical behavior of legged locomotion during both steady and perturbed running. Ultimately, stabilization and economical movement require control of ground forces and center of mass (CM) moments, resulting from the temporal pattern of limb support and placement. Quadrupedal gaits of terrestrial mammals mitigate pitch, roll and yaw moments, but pitch moments are greatest for both trotting and galloping. Studies of CM moments with limb mechanics in running animals guide biorobotic design and control strategies for legged robots.

Andrew A. Biewener is the Charles P. Lyman Professor of Biology and a member of the Department of Organismic and Evolutionary Biology of Harvard University. He also serves as Director of the Concord Field Station, located in Bedford MA, and oversees the Harvard Estabrook Woods in Concord, MA. He currently serves as Department Chair and previously served as President of the American Society of Biomechanics. He is Deputy Editor-in-Chief for the Journal of Experimental Biology as well as serving as an Editor for Biological Letters. His research is on the biomechanics and physiology of animal movement, which includes comparative studies of terrestrial locomotion and avian flight, as well as in the design and implementation of legged robots. In addition to over 100 research papers, he has published a textbook Animal Locomotion (Oxford University Press) on these subjects. Recent research has explored the neuromechanics of limb and muscle function, which seeks to understand how running animals achieve stability when unexpectedly perturbed, in addition to studying the center of mass and limb dynamics of terrestrial locomotion across gaits for enhancing the design of legged robots, such as BigDog. This latter work is in collaboration with Boston Dynamics. He teaches undergraduate and graduate courses on the Structure and Physiology of Vertebrates and on Comparative Biomechanics, and oversees undergraduate and graduate research projects in these areas.

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