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Rapid inversion: running animals and robots swing like a pendulum under ledges.

Mongeau JM, McRae B, Jusufi A, Birkmeyer P, Hoover AM, Fearing R, Full RJ - PLoS ONE (2012)

Bottom Line: The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals.Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling.Quantification of these acrobatic behaviors provides biological inspiration toward the design of small, highly mobile search-and-rescue robots that can assist us during natural and human-made disasters.

View Article: PubMed Central - PubMed

Affiliation: Biophysics Graduate Group, University of California, Berkeley, California, United States of America. jmmongeau@berkeley.edu

ABSTRACT
Escaping from predators often demands that animals rapidly negotiate complex environments. The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals. Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling. Here, we report a novel behavior in small, legged runners that may facilitate their escape by disappearance from predators. We video recorded cockroaches and geckos rapidly running up an incline toward a ledge, digitized their motion and created a simple model to generalize the behavior. Both species ran rapidly at 12-15 body lengths-per-second toward the ledge without braking, dove off the ledge, attached their feet by claws like a grappling hook, and used a pendulum-like motion that can exceed one meter-per-second to swing around to an inverted position under the ledge, out of sight. We discovered geckos in Southeast Asia can execute this escape behavior in the field. Quantification of these acrobatic behaviors provides biological inspiration toward the design of small, highly mobile search-and-rescue robots that can assist us during natural and human-made disasters. We report the first steps toward this new capability in a small, hexapedal robot.

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Flat-tailed house gecko, H. platyurus in its native environment in the rainforests of Singapore.The two panels show a sequence of the inversion behavior from the top (a) and bottom (b) of a fern leaf recorded in the field with high-speed videography. After moving over the robust parts of the fern leaf with a rigid midrib beneath that supported their body weight, the gecko engaged its claws near the tip of the leaf and performed a pendulum-like swing towards the underside.
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pone-0038003-g003: Flat-tailed house gecko, H. platyurus in its native environment in the rainforests of Singapore.The two panels show a sequence of the inversion behavior from the top (a) and bottom (b) of a fern leaf recorded in the field with high-speed videography. After moving over the robust parts of the fern leaf with a rigid midrib beneath that supported their body weight, the gecko engaged its claws near the tip of the leaf and performed a pendulum-like swing towards the underside.

Mentions: We observed the rapid inversion behavior in the gecko’s natural environment, the forests of Singapore (Fig. 3). Geckos (mass = 3.75±0.4 g) ran over the lamina of ferns and stretched their forelimbs outwards as their torso went over the leaf’s edge (Video S5). We studied eleven animals and we observed the behavior in three animals. They anchored their rear legs within the blade of the fern, thus causing the body to swing around towards the underside of the leaf as a result of their inertia. The behavior was analogous to the discovery made in the laboratory and demonstrates its potential effectiveness in traversing the animal’s native habitat.


Rapid inversion: running animals and robots swing like a pendulum under ledges.

Mongeau JM, McRae B, Jusufi A, Birkmeyer P, Hoover AM, Fearing R, Full RJ - PLoS ONE (2012)

Flat-tailed house gecko, H. platyurus in its native environment in the rainforests of Singapore.The two panels show a sequence of the inversion behavior from the top (a) and bottom (b) of a fern leaf recorded in the field with high-speed videography. After moving over the robust parts of the fern leaf with a rigid midrib beneath that supported their body weight, the gecko engaged its claws near the tip of the leaf and performed a pendulum-like swing towards the underside.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368944&req=5

pone-0038003-g003: Flat-tailed house gecko, H. platyurus in its native environment in the rainforests of Singapore.The two panels show a sequence of the inversion behavior from the top (a) and bottom (b) of a fern leaf recorded in the field with high-speed videography. After moving over the robust parts of the fern leaf with a rigid midrib beneath that supported their body weight, the gecko engaged its claws near the tip of the leaf and performed a pendulum-like swing towards the underside.
Mentions: We observed the rapid inversion behavior in the gecko’s natural environment, the forests of Singapore (Fig. 3). Geckos (mass = 3.75±0.4 g) ran over the lamina of ferns and stretched their forelimbs outwards as their torso went over the leaf’s edge (Video S5). We studied eleven animals and we observed the behavior in three animals. They anchored their rear legs within the blade of the fern, thus causing the body to swing around towards the underside of the leaf as a result of their inertia. The behavior was analogous to the discovery made in the laboratory and demonstrates its potential effectiveness in traversing the animal’s native habitat.

Bottom Line: The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals.Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling.Quantification of these acrobatic behaviors provides biological inspiration toward the design of small, highly mobile search-and-rescue robots that can assist us during natural and human-made disasters.

View Article: PubMed Central - PubMed

Affiliation: Biophysics Graduate Group, University of California, Berkeley, California, United States of America. jmmongeau@berkeley.edu

ABSTRACT
Escaping from predators often demands that animals rapidly negotiate complex environments. The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals. Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling. Here, we report a novel behavior in small, legged runners that may facilitate their escape by disappearance from predators. We video recorded cockroaches and geckos rapidly running up an incline toward a ledge, digitized their motion and created a simple model to generalize the behavior. Both species ran rapidly at 12-15 body lengths-per-second toward the ledge without braking, dove off the ledge, attached their feet by claws like a grappling hook, and used a pendulum-like motion that can exceed one meter-per-second to swing around to an inverted position under the ledge, out of sight. We discovered geckos in Southeast Asia can execute this escape behavior in the field. Quantification of these acrobatic behaviors provides biological inspiration toward the design of small, highly mobile search-and-rescue robots that can assist us during natural and human-made disasters. We report the first steps toward this new capability in a small, hexapedal robot.

Show MeSH
Related in: MedlinePlus