Wear of sliding contacts leads to energy dissipation and device failure, resulting in massive economic and environmental costs. Typically, wear phenomena are described empirically, because physical and chemical interactions at sliding interfaces are not fully understood at any length scale. Fundamental insights from individual nanoscale contacts are crucial for understanding wear at larger leng...

This paper analyses the problem of modelling joint friction in robotic manipulators with gear transmissions at joint velocities varying from close to zero until their maximum appearing values. It is shown that commonly used friction models that incorporate Coulomb, (linear) viscous and Stribeck components are inadequate to describe the friction behaviour for the full velocity range. A new frict...

Friction between crystalline bodies is described in a model that unifies elements of dislocation drag, contact mechanics, and interface theory. An analytic expression for the friction force between solids suggests that dislocation drag accounts for many of the observed phenomena related to solid–solid sliding. Included in this approach are strong arguments for agreement with friction dependence...

This paper presents a method to artificially re-create haptic feedback while moving and sliding an arbitrary virtual tool against a virtual deformable body with nonlinear elastic properties. The computation of the response in such general cases is a task which does not yet admit computational solutions suitable for realtime implementation. To address this, we describe an approach based on the b...

Many types of micro-electro-mechanical-system (MEMS) based products are currently employed in a variety of applications. However, high friction in these systems is a problem which limits the development of MEMS devices in which sliding contacts are involved. The aim of this research is to evaluate the effect of boundary slip on the hydrodynamic friction in a low load lubricated MEMS, in particu...

In the present work the influence of a LuGre type friction law [cf. to C. Canudas de Wit, H. Olsson, K.J. Aström, P. Lischinsky, A new model for control of systems with friction, IEEE Transactions on Automatic Control 40 (1995) 419] on the fundamental mechanisms resulting in linear instability of steady sliding in point contacts is investigated. Both a velocity-dependent kinetic friction coeffi...

The feet/ground interaction is one of the major problem in the context of dynamic simulation for walking devices. We focus here about the phenomenon of contact. This paper describes a general model for dynamic simulation of contacts between a walking robot and ground. This model considers a force distribution and uses an analytical form for each force depending only on the known state of the ro...

Study of contact and friction at multiple length scales is necessary for the effective design and analysis of surfaces in sliding microand nano-electromechanical systems (MEMS/NEMS). As loading forces decrease in such applications, the size of the asperity contacts tends to decrease into the nano scale regime. Also with the increase in surface area to volume ratio in such systems, the surface f...

We report laboratory determinations of the shear resistance to sliding melting ice with entrained particles over a hard, impermeable surface. With higher particle concentrations and larger particle sizes, Coulomb friction at particlebed contacts dominates and the shear stress increases linearly with normal load. We term this the sandy regime. When either particle concentration or particle size ...

Orthodontic forces for sliding tooth movement during space closure are applied at a distance from the centre of resistance of the teeth. For this reason, the teeth will tip until contacts are established between the archwire and diagonally opposite corners of the bracket wings. They will also rotate until the wire contacts opposite corners of the ligature tie or the buccal shield with self-liga...