A vehicle with a two-wheel steering system mobile in shallow dense granular media

Abstract

We design a vehicle with a steering system made of two independently rotatable wheels on the front. We quantify the effectiveness of the steering system in the mobility and maneuverability of the vehicle running in a box containing a layer ping-pong balls with a packing density 0.8, below the random close packing value 0.84 in 2D. The steering system can reduce the resistance exerted by the jammed balls formed ahead of the fast-moving vehicle. Moreover, if only one of the two steering wheels rotates, the vehicle can turn into the direction opposite to the rotating wheel. The steering system performs more efficiently if the wheels engage the ping-pong balls better by increasing the contact area between the wheels and the balls. We advocate applying our design to machines moving in granular materials with a moderate packing density.

Studying the Kinetics of a Self-Propelled Cruiser in 2D Granular Media under Gravity

“…However, similar endeavors to study mobile machines in athermal fluids such as nonequilibrium granular materials have been initiated only recently [1], mainly because the nonequilibrium features make developing a governing equation of the system a challenging task [2]. Among the finite attempts tackling this challenge in the literature, except some artificial designs [3][4][5][6][7][8], most of them are bio-inspired, such as mimicking sandfish, lizard and snake [4,[9][10][11][12][13][14][15], insects [16] and clam that uses an intricate way to move forward by swallowing and discharging sands [17,18]. Learning from the nature has the benefit of always having an original counterpart that has been optimised through long evolution to compare with, and the mimicked designs are guaranteed to function under known conditions.…”