Friction in a DC servo positioning system is the main challenge to accurate positioning performance. If it can be accurately estimated, the positioning accuracy can be enhanced. Extensive research literature exists on friction modelling and estimation. The contribution of this work is a simulation-based method for estimating not only friction but also the transfer function of the system in whic...

In this paper, the phenomena of hysteretic behaviour of friction force observed during experiments are discussed. On the basis of experimental and theoretical analyses, we argue that such behaviour can be considered as a representation of the system dynamics. According to this approach, a classification of friction models, with respect to their sensitivity on the system motion characteristic, i...

The evolution of a friction surface geometry with initially directed microscale grooves on a nanoscale polished surface in ring-on-block sliding contact is studied experimentally. Reduced wear and friction is observed when the orientation of grooves coincides with the direction of sliding. A new compressive-vacuum hypothesis of friction force nature under a condition of boundary lubrication is ...

In this paper, we investigate the friction behaviors of graphene flakes sliding on a gold substrate using molecular dynamics simulations. The effects of flake size, flake shape, relative rotation angle between flake and substrate, and crystal orientation of substrate on the friction process are thoroughly studied. It is found that under the same load, the average friction forces per atom are sm...

Reach-to-grasp movements change quantitatively in a lawful (i.e. predictable) manner with changes in object properties. We explored whether altering object texture would produce qualitative changes in the form of the precontact movement patterns. Twelve participants reached to lift objects from a tabletop. Nine objects were produced, each with one of three grip surface textures (high-friction, ...

Single asperity friction experiments using atomic force microscopy (AFM) have been conducted on chemical vapor deposited (CVD) graphene grown on polycrystalline copper foils. Graphene substantially lowers the friction force experienced by the sliding asperity of a silicon AFM tip compared to the surrounding oxidized copper surface by a factor ranging from 1.5 to 7 over loads from the adhesive m...

We study the non-contact friction between an atomic force microscope tip and a metal substrate in the presence of bias voltage. The friction is due to energy losses in the sample created by the electromagnetic field from the oscillating charges induced on the tip surface by the bias voltage. We show that the friction can be enhanced by many orders of magnitude if the adsorbate layer can support...

This survey is devoted to the significant role of various dry friction laws in engineering sciences. Both advantages and disadvantages of a frictional process are illustrated and discussed, but excluding the nature of friction. It is shown how the classical friction laws and modern friction theories exist in today’s pure and applied sciences. Static and dynamic friction models are described. An...

PACS. 82.20K-Potential energy surfaces for chemical reactions. PACS. 71.45N-Calculations of total electronic binding energy. PACS. 68.65-Layer structures, intercalation compolU1ds and superlattices: growth, structure and non-electronic properties. PACS. 61.16D-Electron microscopy determinations (inc. scanning tunnelling microscopy methods). Abstract.-We investigate the microscopic mechanism of ...

We report a quartz crystal microbalance study of sliding friction levels in N2, H2O, and superheated He films adsorbed on Pb(111) substrates alternating in and out of the superconducting state. Reductions in friction upon entry into the superconducting state are greater for N2 than He, consistent with a recent theory that linked electronic friction to adsorbate polarizability. Our work also rev...