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J R Soc Interface. 2018 Feb;15(139). pii: 20170664. doi: 10.1098/rsif.2017.0664. Epub 2018 Feb 14.

Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots.

Author information

1
Department of Integrative Biology, University of California, Berkeley, CA 94720, USA kjayaram@seas.harvard.edu.
2
School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
3
Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA.
4
Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
5
Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
6
Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA 94720, USA.

Abstract

Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size dependence favouring mechanical mediation below 1 kg that we term the 'Haldane limit'. Relying on the mechanical control offered by soft exoskeletons represents a paradigm shift for understanding the control of small animals and the next generation of running, climbing and flying robots where the use of the body can off-load the demand for rapid sensing and actuation.

KEYWORDS:

biomechanics; climbing; mechanical control; robustness

PMID:
29445036
PMCID:
PMC5832722
DOI:
10.1098/rsif.2017.0664
[Indexed for MEDLINE]
Free PMC Article

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