Adaptive Locomotion in Biological Systems Ð How

 it can be Modeled and Understood to build Legged Robots 

 
Professor Avis Cohen 

Department of Biology and Neuroscience and Cognitive Science and

Institute of Systems Research

University of Maryland

 

Locomotion in all its various forms is an oscillatory phenomenon. The limbs swing periodically, or the body moves periodically if limbless. Any form of locomotion is a function of 1) the mechanics of the body, plus the environment, 2) the neural control of the muscles, and 3) the sensory feedback from the body and the environment. All are necessary for fully functional and adaptive locomotion.

 

The spinal circuits for locomotion are distributed along the spinal cord. Each segment has its own oscillatory neural circuit. Successful locomotion requires that the segmental oscillators be coordinated properly. For example, the coupling must produce a constant relative phase among the segments virtually regardless of the frequency of the oscillation. Over the past 20 years, my colleagues and I have been modeling the coupling among the segmental oscillators. The original model sets forth a simple periodic sinusoidal coupling function of the phase difference among the oscillators. We now have evidence that this model is insufficient for the spinal control of swimming in lampreys, primitive vertebrates that we study experimentally and that inspired the original modeling.

 

This talk will describe the mathematical models weÕve developed, including the new data. We will also examine how the use of some known biological principles of control for locomotion, including the neural oscillatory circuits, can be used to build and control legged robots.

 

Friday, February 13, 2004

3:30 Ð 4:30 p.m.

 RM. 1500 EECS