Friction is present in all mechanical systems and causes a wide range of problems for control. The development of friction models and methods to account for friction in control has been an active research area for many years. A promising friction model that is capable of describing a wide array of observed friction phenomena is the LuGre model. This thesis deals with the application of friction...

Recent research on friction in robot joints and transmission systems has considered meshing friction a position-dependent friction component. However, in this paper we show experimental evidence that meshing friction depends highly on joint speed. We identify the meshing friction in the gearboxes of a robotic leg, and we propose a new mathematical model that considers the rate dependency of mes...

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...

A model cell which controls its cation composition and volume by the action of a K-Na exchange pump and leaks for both ions working in parallel is presented. Equations are formulated which describe the behavior of this model in terms of three membrane parameters. From these equations and the steady state concentrations of Na, K, and Cl, values for these parameters in high potassium (HK) and low...

In this paper, a linear parametric friction model is formulated by linearizing a nonlinear empirical friction model in parameters. A proposed decompositionbased control design framework is applied to synthesize the friction compensation scheme. A separate compensator is designed for each type of friction utilizing the most suitable control technique. The nominal friction is compensated by feedf...

Transcranial magnetic stimulation (TMS) is used in several studies to evaluate cortical excitability changes induced by transcranial direct current stimulation (tDCS) of the primary motor cortex. Interpretation of these results, however, is hindered by the very different spatial distribution of the electric field (E-field) induced by the two techniques and by the different target neurons that t...

results a significant higher serum pab value was observed in shift working and daytime nurses (152.28 ± 43.64 hk) in comparison to the control group (63.64 ± 34.41 hk index), p value = 0.001. in day time nurses, also serum pab between male (119.09 ± 47.14 hk) and female (162.53 ± 37.02 hk) in nursing workers was significant, p value = 0.005. in the night shift working nurses, there was also a s...

A new dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles is validated via experiments with an actual passenger vehicle. Contrary to common static friction/slip maps, this new dynamic friction model is able to accurately capture the transient behavior of the friction force observed during transitions between braking and acceleration. A velocitydep...

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...