Event Location: Newell Simon Hall 1305

Abstract: Dynamics in locomotion is highly useful, as can be seen in animals and gradually in robots. For instance, chimpanzees are dynamic climbers that can reach virtually any part of a tree and even move to neighboring trees, while sloths are quasistatic climbers confined only to a few branches. Although dynamic maneuvers are undoubtedly beneficial, only a few engineered systems use them. This is because the design and control are often extremely complicated. Moreover, these dynamic robots mostly locomote horizontally.

This work extends dynamic robotic legged locomotion from horizontal motions such as walking, hopping, and running, to vertical motions such as leaping maneuvers. The proposed mechanism, called DSAC for Dynamic, Single Actuated Climber, resembles the motion of an athlete jumping and climbing inside a chute. Whereas this environment is an unnavigable obstacle for a slow, quasistatic climber, it is an invaluable source of reaction forces for a dynamic climber. The mechanism proposed here will try to achieve dynamic, vertical motion while retaining simplicity in design and control.

DSAC comprises only two links connected by a single oscillating actuator. This simple, open loop motion, almost miraculously propels the robot stably between two vertical walls. A change in the mechanism’s parameters not only changes the stability of the system but also changes the climbing pattern.

I propose to use DSAC to explore minimalist approach to locomotion. I propose first to identify the optimal parameters and control for climbing in this open-loop paradigm by studying variations in robot parameters, environment parameters and control input. Only then will I incrementally add feedback and mechanical complexity to achieve climbing in more difficult environments such as piecewise linear walls.

Committee:Matthew T. Mason, Co-chair

Howie Choset, Co-chair

Christopher G. Atkeson

Kevin M. Lynch, Northwestern University

Andy Ruina, Cornell University