Continuous body 3-D reconstruction of limbless animals

Abstract

Limbless animals such as snakes, limbless lizards, worms, eels, and lampreys move their slender, long bodies in three dimensions to traverse diverse environments. Accurately quantifying their continuous body's 3-D shape and motion is important for understanding body-environment interactions in complex terrain, but this is difficult to achieve (especially for local orientation and rotation). Here, we describe an interpolation method to quantify continuous body 3-D position and orientation. We simplify the body as an elastic rod and apply a backbone optimization method to interpolate continuous body shape between end constraints imposed by tracked markers. Despite over-simplifying the biomechanics, our method achieves a higher interpolation accuracy (~50% error) in both 3-D position and orientation compared with the widely-used cubic B-spline interpolation method. Beyond snakes traversing large obstacles as demonstrated, our method applies to other long, slender, limbless animals and continuum robots. We provide codes and demo files for easy application of our method.

References in corpus (5)

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• Sidewinding with minimal slip: Snake and robot ascent of sandy slopes
• Undulatory locomotion of {\it C. elegans} on wet surfaces
• Emergence of the advancing neuromechanical phase in a resistive force dominated medium
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Cited by in corpus (4)

• Locomotor transitions in the potential energy landscape-dominated regime
• Snakes combine vertical and lateral bending to traverse uneven terrain
• A physics-informed, vision-based method to reconstruct all deformation modes in slender bodies
• Contact feedback helps snake robots propel against uneven terrain using vertical bending