Vibration can enhance stick-slip behavior for granular friction

Stabilizing stick-slip friction.

Even the most regular stick-slip frictional sliding is always stochastic, with irregularity in both the intervals between slip events and the sizes of the associated stress drops. Applying small-amplitude oscillations to the shear force, we show, experimentally and theoretically, that the stick-slip periods synchronize. We further show that this phase locking is related to the inhibition of slo...

Fracture and friction: Stick-slip motion.

We discuss the stick-slip motion of an elastic block sliding along a rigid substrate. We argue that for a given external shear stress this system shows a discontinuous nonequilibrium transition from a uniform stick state to uniform sliding at some critical stress which is nothing but the Griffith threshold for crack propagation. An inhomogeneous mode of sliding occurs when the driving velocity ...

Dynamic scaling in stick-slip friction

Robust adaptive stick-slip friction compensation

In this paper, a robust adaptive tracking control scheme is proposed for compensation of the stick-slip friction in a mechanical servo system. The control scheme has a sliding control input to compensate friction forces. The gain of the sliding control input is adjusted adaptively to estimate the linear bound of the stick-slip friction. By introducing the sliding control input, the global stabi...

Stick-slip fluctuations in granular drag.

We study fluctuations in the drag force experienced by an object moving through a granular medium. The successive formation and collapse of jammed states give a stick-slip nature to the fluctuations which are periodic at small depths but become "stepped" at large depths, a transition that we interpret as a consequence of the long-range nature of the force chains and the finite size of our exper...