A vehicle with a two-wheel steering system mobile in shallow dense granular media
This addresses mobility challenges for machines operating in moderately dense granular materials, representing an incremental improvement in vehicle design.
The researchers tackled the problem of vehicle mobility in dense granular media by designing a two-wheel steering system, finding that it reduces resistance from jammed particles and enables turning by rotating a single wheel, with effectiveness increasing through better wheel-ball contact.
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.