Friction force microscopy measurements on the vacuum-cleaved (001) surfaces of KF, KCl and KBr have been carried out. All surfaces exhibit atomically flat terraces with monatomic steps aligned preferentially along low-index lattice directions. Stick-slip lateral forces with the lattice periodicity are observed on all surfaces. Tip-sample contact creates higher friction domains on the terraces o...

Joint friction is a major problem in accurate robot position control, particularly during low-speed, small-amplitude tasks. This paper proposes a simple, practical, and e!ective method to compensate for joint friction, using a six-axis force/torque sensor mounted under the manipulator. From these measurements, joint torques are estimated and used in a torque controller, which virtually eliminat...

The importance of friction and wear control cannot be over emphasized for economic reasons and longterm reliability. The savings can be substantial, and these savings can be obtained without the deployment of investment. Tribology is crucial to modern machinery which uses sliding and rolling surfaces. This article describes the tribological behavior analysis for the conventional materials i.e. ...

We have used molecular dynamics simulations to examine friction when two diamond (1 11) surfaces are placed in sliding contact. We find that flexible hydrocarbon species, chemically bound to the diamond surface, can lead to a significant reduction of the calculated friction at high loads. In addition to clarifying the effects of such species on atomic-scale friction at diamond interfaces, these...

The paper deals with the measurement, identification and compensation of low velocity friction in positioning systems. The introduced algorithms are based on a linearized friction model, which can easily be introduced in tracking control algorithms. The developed friction measurement and compensation methods can be implemented in simple industrial controller architectures, such as microcontroll...

Melt produced by friction during earthquakes may act either as a coseismic fault lubricant or as a viscous brake. Here we estimate the dynamic shear resistance (tau(f)) in the presence of friction-induced melts from both exhumed faults and high-velocity (1.28 meters per second) frictional experiments. Exhumed faults within granitoids (tonalites) indicate low tau(f) at 10 kilometers in depth. Fr...

The resistance against rolling of a rigid cylinder on a flat viscous surface is investigated. We found that the rolling-friction coefficient reveals strongly non-linear dependence on the cylinder’s velocity. For low velocity the rolling-friction coefficient rises with velocity due to increasing deformation rate of the surface. For larger velocity, however, it decreases with velocity according t...

The effect of C60 molecular rotation on the nanotribological properties of C60 single crystal surfaces has been studied by atomic/frictional force microscopy. The orientational order-disorder phase transition, in which the high temperature C60 free rotation is reduced to a low temperature hindered rotation, is shown to give rise to an abrupt change in friction and adhesion. This change in frict...