The research objectives of this award are to develop and implement a biomechanically relevant, unified theory of legged dynamics that spans walking and running, and to demonstrate this theory on a new bipedal robot, ATRIAS. To date, a legged machine whose dynamic behavior can approach the performance of human walking and running, including transitions between these two gaits, does not exist. The research will result in principled models of gait and gait transitions with human-like leg dynamics, in generalized models for manipulating cyclic hybrid dynamic systems to achieve different goal behaviors, and in the verification and demonstration of this new scientific understanding with a bipedal robot. The research progresses from analyzing simplified gait models that capture the essential dynamics of human locomotion to integrating these modules in a core dynamics model of human gait. Goal behavior manipulations will be approached using the influence of parameters on the shape of the Poincare map in these cyclic dynamic systems. Experimental verification on the robot will demonstrate and refine the theoretical progress. Deliverables include modeling and simulation software, experimental verification and demonstration on robot hardware, documentation of research results, and engineering student education and research experience.
The results of this research will provide the opportunity to create control algorithms for powered legged systems that enable functionally versatile behaviors similar to animals and humans. Examples include prosthetic legs and exoskeletons that provide human users with human-like leg dynamics during walking, running, and the transitions between these gaits. Other examples include legged robots that achieve robust and efficient dynamic turning behaviors. The results will be disseminated to encourage commercial applications and further development. A simulation of the robot implementation of the results will be posted online to engage healthy competition in the development of control algorithms for powered legs. Graduate and undergraduate students will benefit through classroom integration, research involvement, and a "tree of mentoring" where the supported personnel will advise and mentor undergraduate robotics club students.
