Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Terradynamically streamlined shapes in animals and robots enhances
  traversability through densely cluttered terrain   Many animals, modern aircraft, and underwater vehicles use streamlined body
shapes that reduce fluid dynamic drag to achieve fast and effective locomotion
in air and water. Similarly, numerous small terrestrial animals move through
cluttered terrain where 3-D, multi-component obstacles like grass, shrubs,
vines, and leaf litter resist motion, but it is unknown whether their body
shape plays a major role in traversal. Few ground vehicles or terrestrial
robots have used body shape to effectively traverse cluttered terrain. Here, we
challenged forest-floor-dwelling discoid cockroaches possessing a thin, rounded
body to traverse tall, narrowly spaced, vertical, grass-like compliant beams.
Animals displayed high traversal performance (79 +/- 12% probability and 3.4
+/- 0.7 s time). Although we observed diverse traversal strategies, cockroaches
primarily (48 +/- 9 % probability) used a novel roll maneuver, allowing them to
rapidly traverse obstacle gaps narrower than half body width (2.0 +/- 0.5 s
traversal time). Reduction of body roundness by addition of artificial shells
nearly inhibited roll maneuvers and decreased traversal performance. Inspired
by this discovery, we added a thin, rounded exoskeletal shell to a legged robot
with a nearly cuboidal body, common to many existing terrestrial robots.
Without adding sensory feedback or changing the open-loop control, the rounded
shell enabled the robot to traverse beam obstacles with gaps narrower than
shell width via body roll. Terradynamically streamlined shapes can reduce
terrain resistance and enhance traversability by assisting effective body
reorientation via distributed mechanical feedback. Our findings highlight the
need to consider body shape to improve robot mobility in real-world terrain
often filled with clutter, and to develop better locomotor-ground contact
models to understand interaction with complex terrain.

25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph