Traditionally the positioning of pneumatic actuators has been limited to movement between preset stops or switches. The restricting factors preventing the use of pneumatic cylinders for accurate servo-control arise from highly nonlinear dynamic properties such as air compressibility and friction effects, which combine to severely degrade time response and positional accuracy. Many real systems ...

An anti-friction Babbitt alloy-coated bearing made by a casting process is a journal bearing, which is used in an ore cone crusher eccentric. The main purpose of the Babbitt coated eccentric is to provide a low friction to support and guide a rotating shaft. Despite the fact that the Babbitt-coated eccentric offers a low friction coefficient and can be operated without a continuous supply of lu...

Lateral Force Microscopy (LFM) studies were carried out on cleaved calcite sections in contact with solutions supersaturated with respect to otavite (CdCO3) or calcite-otavite solid solutions (SS) as a means to examine the potential for future application of LFM as a nanometer-scale mineral surface composition mapping technique. Layer-by-layer growth of surface films took place either by step a...

Rubber exhibits unusual sliding friction. When rubber is slid on a hard, rough substrate, the surface asperities of the substrate exert oscillating forces on the rubber surface leading to energy ‘‘dissipation’’ via the internal friction of the rubber. I estimate this contribution to the friction force and compare the results with the experimental data of Grosch. Because of its low elastic modul...

Recent calculations [Guerra et al, Nature Materials, 9 634 (2010)] have predicted that gold nanocrystals slide on graphite with two radically different friction coefficients depending on their speeds. At low speeds (~μm/sec), nanocrystals on graphite are expected to possess higher friction, consistent with previous studies of thermal diffusion of gold on graphite and on graphene. At high slidin...

The development of Scanning Force Microscopy has provided us with tools to study friction and wear on the nanometer scale. The atomic granularity of matter shows up in the lateral force which is necessary to slide a small contact over a flat surface. Also, mechanical damage of a sample surface can be monitored with monolayer resolution [1]. The laws which determine the dependence of friction on...

The paper presents experimental results of friction parameter identification for two different systems: rotational arms of a direct-drive spherical manipulator and linear slide tables. Parameters of the static part of the LuGre friction model are estimated. Several experiments are reported in which selected friction compensation methods are employed for tracking at low velocities. Two compensat...

The melting of ultrathin lubricant film by friction between atomically flat surfaces is studied. The additive noises of the elastic shear stress and strain, and the temperature are introduced for building a phase diagram with the domains of sliding, stick-slip, and dry friction. It is shown that increase of the strain noise intensity causes the lubricant film melting even at low temperatures of...

Tribology is the science and technology of interacting solid surfaces in relative motion, and its topics include the study of lubricants, lubrication, friction, wear, and bearings. It is estimated that friction and wear cost the US economy 6% of the gross national product [1]. For example, 5% of the total energy generated in an automobile engine is lost to frictional resistance. Also notable ar...