An adaptive control scheme for emergency braking of vehicles is designed based on a LuGre dynamic model for the tire/road friction. The wheel angular speed and longitudinal vehicle acceleration information are used to design an observerestimator for vehicle velocity, friction internal state and friction parameters. A Lyapunov-based stabilizing controller is designed to achieve near maximum brak...

We investigate the effect of friction on domain formation in disoriented chiral condensate. Including a friction term, we solve the equation of motion of the linear sigma model fields, in the Hartree approximation. With boostinvariance and cylinderical symmetry, irrespective of friction, on average, we donot find any indication of domain like formation with quenched initial condition. However, ...

friction is a nonlinear phenomenon which has destructive effects on performance of control systems. to obviate these effects, friction compensation is an effectual solution. in this paper, an adaptive technique is proposed in order to eliminate limit cycles as one of the undesired behaviors due to presence of friction in control systems which happen frequently. the proposed approach works for n...

1. Three men and seven women, 25-40 yr of age, were asked to use the thumb and index fingers to grasp, lift, and hold the armature of a linear motor generating a 2.0-N opposing force (simulating an object weighing approximately 200 g) for 2 s. The surface in contact with the fingers was composed of smooth or polyamide plastic etched with 1.0-mm high Braille beads separated at 2.0- or 3.0-mm int...

Friction-induced moments and subsequent cup loosening can be the reason for total hip joint replacement failure. The aim of this study was to measure the in vivo contact forces and friction moments during walking. Instrumented hip implants with Al2O3 ceramic head and an XPE inlay were used. In vivo measurements were taken 3 months post operatively in 8 subjects. The coefficient of friction was ...

A review of the problem of aircraft skidding on Naval airfields during landings and a thorough literature search on the work conducted on friction coefficient were made. The literature search revealed that much ,vork has been conducted on basic theoretical studies of friction coefficient, on development of friction measuring devices, and on investigations to determine the factors which affect t...

The inhomogeneous distribution of surface asperities generated by deformation induces variability in the friction and initiates strain localizations during metal forming. The friction literature generally does not account for the strong influence localized variations in material properties have on the friction behavior. A prototype apparatus was developed that measures the friction behavior und...

The paper deals with experimental friction identificat ion method of a DC motor. For precise positioning tasks a friction phenomenon plays a large problem. For this a friction has to be identified and subsequently compensated if it is important. At first the paper deals with basic friction models. In the next section the DC motor mathemat ical model is stated. The DC motor friction identificat ...

This paper describes a new friction model, called the “brush model“, suitable for haptic rendering in virtual environments. A novel two-layer multiasperity surface contact model is presented that provides real-time rendering of friction forces at haptic refresh rates. This new friction model has several advantages; of particular importance is the accuracy with which it handles static friction a...

Friction is responsible for several servomechanism limitations, and their elimination is always a challenge for control engineers. In this paper, model-based feedback compensation is studied for servomechanism tracking tasks. Several kinetic friction models are employed and their parameters identified experimentally. The effects of friction compensation on system response are examined using des...