Leg design and stair climbing control for the RHex robotic Hexapod

Abstract

The goals of the research in this thesis are twofold. First, I designed and tested a stair-traversing controller, which allows RHex to ascend and descend a wide variety of human sized stairs. I tested the stair-ascending controller on nine different flights of stairs, and the stair-descending controller on four different flights of stairs. Rhex was run ten times on each flight, and met with only a single failure out of the one-hundred-and-thirty attempts. Second, we built and tested three competing leg designs. The second and third leg designs proved adequate for use on RHex, enabling dynamic and off road behaviors. The stair controller and leg design processes both drew on lessons from biology, in a process in we call "functional biomimesis". This framework guided us while we mimicked the functionally important features of animal morphology and behavior, while ignoring those features that are irrelevant to locomotion. We compared these advances with previous work in the field, including work on wheeled and tracked vehicles, as well as stair-traversing legged robots. Finally, RHex is a new robot, so we present an overview of RHex's basic mechanical and electrical designs.