| Volume 27 Issue 5 - Publication Date: 1 May 2008 |
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| Legless Locomotion:
A Novel Locomotion
Technique for Legged
Robots |
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| Ravi Balasubramanian Computer Science and Engineering,
University of Washington,
Box 352350,
Seattle, WA 98195-2350, USA, Alfred A. Rizzi Boston Dynamics,
614 Massachusetts Avenue,
Cambridge, MA 02139, USA and Matthew T. Mason Robotics Institute,
Carnegie Mellon University,
5000 Forbes Avenue,
Pittsburgh, PA 15213-3890, USA |
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| We present a novel locomotion strategy called legless locomotion that
allows a round-bodied legged robot to locomote approximately when
it is high-centered. Typically, a high-centered robot is stuck since the
robot’s legs do not touch the ground. Legless locomotion uses the legs
as a reaction mass to set up oscillatory body rotations which when
coupled with ground contact gradually translate the robot. Legless
locomotion’s continuous dynamics differs from previously studied locomotion
methods because of the simultaneous interaction of gravityinduced
oscillations, a configuration-dependent system inertia, and
non-holonomic contact constraints. This paper employs simple models
to capture the complex dynamics and uses the intuition developed
from the models to develop gaits that provide planar accessibility. We
also present a quantification of legless locomotion’s properties using
simulations and motion-capture experiments. |
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| Multimedia Key |
= Video |
 = Data |
= Code |
= Image |
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Extension |
Type |
Description |
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1 |
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Example
1: RHex escapes after becoming highcentered. (2.31 MB) mp4 |
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2 |
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Example
2: A round-bottomed RHex locomotes
by swinging its legs. (8.94 MB) mp4 |
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3 |
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Example
3: A simulation of the sphere–plane
contact kinematics illustrates a
sphere can translate in any direction
using roll, pitch, and yaw
oscillations. (1.96 MB) mp4 |
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4 |
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Example
4: Experiment showing RRRobot locomoting
sideways. (3.26 MB) mp4 |
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5 |
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Example
5: Simulation showing RRRobot locomoting
sideways. (8.87 MB) mp4 |
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6 |
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Example
6: Experiment showing RRRobot locomoting in a counter-clockwise path. (8.89 MB) mp4 |
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7 |
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Example
7: Simulation showing RRRobot locomoting
in a counter-clockwise path. (14.4 MB) mp4 |
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8 |
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Example
8: Animation of experiment motion
capture showing legless locomotion
gait transitions. (7.17 MB) mp4 |
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