Multi-Material Anisotropic Friction Wheels for Omnidirectional Ground Vehicles

In this paper, a novel omnidirectional vehicle with anisotropic friction wheels is presented. The proposed wheel has a series of bendable “nodes” on its circumference, each of which is made of two materials with differing friction properties: one material exhibits high friction, and the other exhibits low friction. The high friction section of the node generates a high traction force, while the low friction section enables the wheel to passively slide. The wheels are arranged such that the robot wheel exhibits high traction in its driving direction (much like a conventional tire), but low traction when sliding laterally. Exploiting this “anisotropic friction” property, the proposed wheel enables a vehicle to realize omnidirectional motion (i.e. the vehicle can move any direction within the plane—forward, back, or laterally). While many other omnidirectional wheel drives exist, the proposed wheel is simpler than any other existing design because the wheel is composed of a single, moldable element. This paper summarizes the design of the proposed wheel and presents a comparison between a small omnidirectional vehicle that uses the proposed wheel and an omnidirectional vehicle that uses conventional wheels.