An apparatus comprises a body having a torus skin with inner and outer layers,
and a drive system configured to propel the apparatus by moving the inner layer
relative to the outer layer. The active skin propulsion system allows movement
and steering of a device. A drive system includes a plurality of drive segments
coupled together so that the skin engaging unit of the drive segment frictionally
moves the inner layer of the torus skin relative to the outer layer of the torus
skin. As a result of the relative skin motion and contact with the surface by the
outer layer of the torus skin, the body is propelled and may be steered.