David Lee, PhD to Discuss Biomechanics in Robotic Locomotion

David Lee, PhD, College of Sciences at UNLV will be discussing biomechanics in robotic locomotion in a talk titled, “Bio-Robotics” on April 9th, 2008 at the UNLV Foundation Room at 12 PM at the Nevada Biotechnology and Bioscience Consortium luncheon. The public is welcomed. Dr. Lee has been studying the mechanical principles of legs and joints in animals. His work has contributed to the mechanical design and control of BigDog, the world's most advanced, four legged robot built by Boston Dynamics. The video of the four legged mechanical robot has become one of the most-watch videos on the internet.

It was his research in comparative biomechanics of running, jumping, and climbing in legged animals, primarily in quadrupeds but also in bipedal birds and humans that helped the designers of BigDog. Comparative biomechanics can show the complex dynamics that underlay animal movement in terrestrial environments.

The musculoskeletal mechanics that make animal movement possible are described by high-speed motion capture or high-speed x-ray imaging during locomotion. These force (kinetic) and movement (kinematic) data are combined to describe the dynamics of locomotion.

Dr. Lee reports, “As legged walkers and runners ourselves, the underlying dynamics are often taken for granted - yet the achievement of dynamic stability in legged robots on a smooth floor, let alone in real-world environments, has proven a formidable engineering challenge. We model the action of muscle-tendon system(s) about a given joint as a serial actuator and spring. By this technique, the experimental joint moment is imposed while the combined angular deflection of the actuator and spring are constrained to match the experimental joint angle throughout the stance duration. The same technique is applied to the radial leg (i.e., shoulder/hip-to-foot). The spring constant that minimizes total actuator work is considered optimal…” Watching the video of BigDog, one can see the complexity of a walking robot.

Dr. Lee is also interested in relating leg and joint mechanics to muscle function as a promising approach to understanding joint dysfunction in osteoarthritis. He will be speaking April 9,2008 at the next meeting of the Nevada Biotechnology and Bioscience Consortium at UNLV campus. For more information or to RSVP, you can eamil Jrebholz@cvbt.com or call Judy Rebholz at 702-839-7222.