The present work aims at contributing to the study of the complex phenomenon of wear of pin on disc contact in dry sliding friction between two material couples (bronze/steel and unsaturated polyester virgin and charged with graphite powder/steel). The work consists of the determination of the coefficient of friction, the study of the influence of the tribological parameters on this coefficient...

In this paper we present an energy-based algorithm to minimize limit cycles in dynamically balancing wheeled inverted pendulum (IP) machines. Because the algorithm is not based on absolute values of parameters, the performance is robust and accounts for mechanical reconfiguration and wear. The effects of phenomena such as drive-train friction, rolling friction, backlash and sensor bandwidth are...

This paper describes some computer simulations of the breakage induced in a two-dimensional particle bed by the descent of a single Ž large grinding ball. These are approximate experiments related to ball-milling that are tractable by the simulation technique i.e., involve . relatively few particles . As a result of the impact of the grinding ball, the particles in the bed are broken andror sca...

The paper presents application of an e nergy-based finite e lement and a local rel axation method to computer calculation of deformation of a ring made of hyperelastic material. T he present study consi ders a surface friction mechanism. This mechanism is a physical phenomenon counteracting the relative motion of the c ontacting bodies. Friction causes loss of e nergy the dissipation of which i...

It is likely that cold molecular clouds form at high redshift, before galaxies. Considering these cold clouds instead of hot homogeneous gas as the main baryonic component of proto-galactic halos may affect several issues during galaxy formation. In particular, the baryonic matter loses angular momentum through dynamical friction on the dark matter halo. In numerical simulations using hot gas f...

The friction pair of piston rings and cylinder liner is one of the most important friction couplings in an internal combustion engine. It influences engine efficiency and service life. Under the excitation of piston slaps, the dynamic deformation of cylinder liner is close to the surface roughness magnitudes, which can affect the friction and lubrication performance between the piston rings and...

In this paper, we investigate the planar dynamic pivoting problem, in which a pinched object is reoriented to a desired pose through wrist swing motion and grip force regulation. Traditional approaches based on friction compensation do not work well for this problem, as we observe the torsional friction at the contact has large uncertainties during pivoting. In addition, the discontinuities of ...

The objective of the article is to evaluate the impact of the friction force mouse-pad in the contraction level of the forearm muscles M. extensor carpi ulnaris, M. extensor digitorum and M. extensor carpi radialis longus. A standard protocol of mouse movements was performed involving horizontal, vertical and diagonal mouse displacements drag-anddrop type. The operators were instructed to execu...

Nonlinearities degrade considerably performances in motion control systems. Nonlinear friction is a major source of many serious problems such as wear, tracking errors and limit cycles. There has been an extensive research activity dealing with the design of compensating techniques. The approaches cited in the litterature can be divided into: free model compensation or model based compensation ...