@article {36, title = {Crawling on directional surfaces}, journal = {International Journal of Non-Linear Mechanics}, volume = {61}, year = {2014}, pages = {65-73}, abstract = {

In this paper we study crawling locomotion based on directional frictional interactions, namely, frictional forces that are sensitive to the sign of the sliding velocity. Surface interactions of this type are common in biology, where they arise from the presence of inclined hairs or scales at the crawler/substrate interface, leading to low resistance when sliding {\textquoteleft}along the grain{\textquoteright}, and high resistance when sliding {\textquoteleft}against the grain{\textquoteright}. This asymmetry can be exploited for locomotion, in a way analogous to what is done in cross-country skiing (classic style, diagonal stride). We focus on a model system, namely, a continuous one-dimensional crawler and provide a detailed study of the motion resulting from several strategies of shape change. In particular, we provide explicit formulae for the displacements attainable with reciprocal extensions and contractions (breathing), or through the propagation of extension or contraction waves. We believe that our results will prove particularly helpful for the study of biological crawling motility and for the design of bio-mimetic crawling robots.

}, keywords = {bio-mimetic micro-robots, cell migration, crawling motility, directional surfaces, self-propulsion}, doi = {10.1016/j.ijnonlinmec.2014.01.012}, author = {Paolo Gidoni and Giovanni Noselli and Antonio DeSimone} } @article {35, title = {Discrete one-dimensional crawlers on viscous substrates: achievable net displacements and their energy cost}, journal = {Mechanics Research Communications}, volume = {58}, year = {2014}, pages = {73{\textendash}81}, abstract = {

We study model one-dimensional crawlers, namely, model mechanical systems that can achieve self-propulsion by controlled shape changes of their body (extension or contraction of portions of the body), thanks to frictional interactions with a rigid substrate. We evaluate the achievable net displacement and the related energetic cost for self-propulsion by discrete crawlers (i.e., whose body is made of a discrete number of contractile or extensile segments) moving on substrates with either a Newtonian (linear) or a Bingham-type (stick-slip) rheology. Our analysis is aimed at constructing the basic building blocks towards an integrative, multi-scale description of crawling cell motility.

}, keywords = {cell migration, cell motility, crawling motility, limbless locomotion, motility on a solid substrate, self-propulsion, soft biomimetic robots}, doi = {10.1016/j.mechrescom.2013.10.023}, author = {Giovanni Noselli and Amabile Tatone and Antonio DeSimone} } @article {30, title = {Crawlers in viscous environments: linear vs. nonlinear rheologies}, journal = {International Journal of Non-Linear Mechanics}, volume = {56}, year = {2013}, pages = {142-147}, abstract = {

We study model self-propelled crawlers which derive their propulsive capabilities from the tangential resistance to motion offered by the environment. Two types of relationships between tangential force and slip velocity are considered: a linear, Newtonian one and a nonlinear one of Bingham-type. Different behaviors result from the two different rheologies. These differences and their implications in terms of motility performance are discussed. Our aim is to develop new tools and insight for future studies of cell motility by crawling.

}, keywords = {cell migration, cell motility, crawling motility, motility on a solid substrate, self-propulsion, soft biomimetic robots}, doi = {10.1016/j.ijnonlinmec.2013.02.007}, author = {Antonio DeSimone and Federica Guarnieri and Giovanni Noselli and Amabile Tatone} }