TALK: Controlling the Next Generation of Bipedal Robots
Speaker: Aaron Ames, Texas A&M University
Date: Wednesday, February 27 2013
Time: 4:00PM to 5:00PM
Location: 3-270
Host: John Leonard, MIT
Contact: John Leonard, jleonard@mit.edu
Relevant URL: http://www.bipedalrobotics.com/
Abstract:
Humans have the ability to walk with deceptive ease, navigating everything from daily environments to uneven and uncertain terrain with efficiency and robustness. Despite the simplicity with which humans appear to ambulate, locomotion is inherently complex due to
highly nonlinear dynamics and forcing. Yet there is evidence to suggest that humans utilize a hierarchical subdivision among cortical control, central pattern generators in the spinal column, and proprioceptive sensory feedback. This indicates that when humans perform motion primitives, potentially simple and characterizable
control strategies are implemented. If these fundamental mechanisms underlying human walking can be discovered and formally understood, human-like abilities can be imbued into the next generation of robotic devices with far-reaching applications ranging from prosthesis to legged robots for space exploration and disaster response.
This talk presents the process of formally achieving bipedal robotic walking through controller synthesis inspired by human locomotion, and demonstrates these methods through examples of experimental realization on multiple bipedal robots. Motivated by the hierarchical control present in humans, we begin by viewing the human as a “black box” and describe outputs, or virtual constraints, that appear to
characterize human walking. By considering the equivalent outputs for
the bipedal robot, a novel type of control Lyapunov function (CLF) can
be constructed that drives the outputs of the robot to the output of the human; moreover, the parameters of this CLF can be optimized so that stable robotic walking is provably achieved while simultaneously producing outputs of the robot that are as close as possible to those of a human. This CLF forms the basis for a Quadratic Program (QP) yielding locomotion that dynamically accounts for torque and contact constraints. The end result is the automatic generation of bipedal
robotic walking that is remarkably human-like and is experimentally
realizable, as will be evidenced by the demonstration of the resulting
controllers on multiple robotic platforms. Future work related to
unifying locomotion and manipulation in humanoid robots via CLF based QPs will be discussed in the context of dynamic maneuvers such as vertical ladder climbing and multi-contact locomotion and manipulation behaviors.
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