Exploiting the Global Dynamics Structure of Whole-Body Humanoid Motion - Getting the “Knack” of Roll-and-Rise Motion

Abstract

Dexterity of human behavior arises from the ability to discover and exploit so-called “knacks”, or the essential reference frames (coordinates in the phase space) for successful control under unknown perturbations. This strategy differs from the traditional robot control in that it only partially specifies/controls the phase space trajectory, pushing the system into a desired natural dynamics, letting it do the job. As the first example of such a strategy, we investigated a “roll-andrise” motion, a fully dynamic whole-body motion with unpredictable perturbations due to multiple contacts with the ground. The “knacks” of the motion are identified and analyzed by a systematic search of the phase space. A successful experiment with an adult-size whole body humanoid robot is presented; it rose from a flat-lying posture to a crouching posture within 2 seconds.