Abstract:
Many of our interactions with the environment involve making and breaking contacts. However, it is not always obvious how one should reason about these intermittent contacts (sequence, timings, locations) in an online and adaptive way. This is particularly relevant in gait generation for legged locomotion control, where it is standard to simply predefine and fix the contact sequences and timings. In this talk, I will argue that abstracting away the complications of instantaneous considerations (acceleration and forces) and reasoning about contacts in terms of impulse generation capability allows the robot to assess the usefulness of contacts. This allows it to determine, online, which limbs should break contact, and where to place them next, while maintaining an interlimb coordination. I will show that this physical reasoning framework is sufficient to generate both periodic and aperiodic gaits adaptively, and exhibits, as emergent behavior, gait transitions with speed, as well as cost of transport reduction with gait transitions.

Committee:
Chris Atkeson
David Held
Oliver Kroemer
Leonid Keselman