Pioneers of Behavior-Based Robotics
For the first several decades of development in robotics, the top-down approach dominated the field. As the top-down approach began to have difficulty managing the explosive increase in data that came with environments of increased complexity, a new approach began to be taken more seriously within the field of robotics.
When Rodney Brooks began experimenting with an entirely different approach to robots, he was not taken that seriously. He was considered to be on the fringe of real robotics, not a serious player. As it became clear that the top-down approach would not easily "scale-up" as it was originally hoped, the behavior-based approach of Brooks' "subsumption architecture" offered an intriguing alternative. Brooks' robots were producing increasingly complex behavior in all manner of environments that would stymie traditional robots. Over time, Brooks went from being on "the fringe" to being at the center of late 20th century and early 21st century robotics.
NOTE: This is a video clip from a Discovery Channel program that is no longer available for purchase. Originally posted on YouTube. Other excellent robot videos are available for purchase at the Discovery Channel Website.
Mark Tilden, at Los Alamos National Laboratory, builds robots that are also examples of a behavior-based architecture. His work is often included in an approach called "artificial life" -- which can describe both physical robots and mathematical objects that exist only in a virtual environment on a computer.
Story about Mark Tilden (optional reading)