Abstract: Disclosed are steerable units that enable the variability of the friction force's magnitude and direction by using rolling contacts, in which the angle of the rolling contacts with respect to the surface containing the steerable unit can be controlled, as an object's frictional surface. This allows an object to adjust the direction and magnitude of the force it transfers through friction and also allows the received frictional force's direction and magnitude to be varied by the receiving object's rolling contacts. Also disclosed are applications of the steerable units in various machines.