Introducing the "SPHERICLE": an experimental testbed for research and teaching in nonholonomy

In this paper we describe an experimental apparatus developed in our laboratory for research and advanced teaching purposes. The device consists in an untethered spherical vehicle that autonomously rolls on the laboratory floor, and can reach arbitrary positions and orientations in the environment. The kinematics of the vehicle are nonholonomic, and result from the combination of the kinematics of two classical nonholonomic systems, namely, a unicycle and a plate-ball system. The “sphericle” however introduces features that are new with respect to both, which fact renders its study particularly interesting.