Figure 2.

Illustration of the geometric and motion model for C .elegans: (A) Illustration of the notations used to define the worm centerline and width profile. (B) The worm crawling motion model can be characterized by a peristaltic progression factor ${\displaystyle \eta }$ along the worm central axis and deformation ${\displaystyle \beta }$. (C) Illustration of the radial displacement of the midpoint. (D) Illustration of the contraction/extension operator.