A new dynamic friction model for modeling of elliptical vibration assisted turning (EVAT) was developed in this research. The periodic change of the friction force direction is known to be one of the most important causes of this phenomenon. In modeling of machining processes (including the EVAT process), static Coulomb friction model was employed by most of the researchers. Because of the peri...

Based on distributions theory to continuous time systems with friction using the this paper presents a batch on-line method for the parameter identification of the modified LuGre friction model. Mainly it applies the results of the identification procedures based on distributions theory to continuous time systems with friction. There are defined the so called generalized friction dynamic system...

We studied adjustments of digit forces to changes in the friction. The subjects held a handle statically in a three-digit grasp. The friction under each digit was either high or low, resulting in eight three-element friction sets (such grasps were coined the grasps with complex friction pattern). The total load was also manipulated. It was found that digit forces were adjusted not only to the s...

The tribological properties of two-dimensional (2D) atomic layers are quite different from three-dimensional continuum materials because of the unique mechanical responses of 2D layers. It is known that friction on graphene shows a remarkable decreasing behavior as the number of layers increases, which is caused by the puckering effect. On other graphene derivatives, such as graphene oxide (GO)...

In rehabilitation training, high-fidelity simulation environments are needed for reproducing the effects of slippery surfaces, in which potential balance failure conditions can be reproduced on demand. Motivated by these requirements, this article considers the design of variable-friction devices for use in the context of human walking on surfaces in which the coefficient of friction can be con...

In this paper, the tracking problem for robot manipulators in the presence of unknown friction and modeling uncertainties is considered. A composite tracking control scheme is proposed in which an adaptive friction estimation is used to estimate the extent of friction and a robust controller is then designed to enhance the overall stability and robustness. It is shown that the design of the fri...

This paper examines the effect of friction model on the simulation accuracy of a hydraulic cylinder by using three friction models: a steady-state friction model, the LuGre model, and the new modified LuGre model. Hydraulic cylinder’s behaviors were measured under sinusoidal input to the servo valve. Simulations were conducted under the same conditions as the experiments. The comparisons of sim...

Friction forces acting on rotators may promote their alignment and therefore eliminate degrees of freedom in their movement. The alignment of rotators by friction force was shown by experiments performed with different spinners, demonstrating how friction generates negentropy in a system of rotators. A gas of rigid rotators influenced by friction force is considered. The orientational negentrop...

Distributions of contact stresses at the neutral point in metal forming are very hard to be properly predicted due to the complex interface situation and lack of suitable friction models. In this paper, the dynamic friction model in which the friction depends on both time rate of strain and normal pressure has been applied to predict contact stresses in cylinder upsetting. Case studies have sho...

Friction is an undesired phenomenon in many drive systems. Feedforward of a suitable estimate of friction is an effective method to compensate the friction-dependent position errors in the steady state. The speed of reconstruction of the real friction is crucial for the grade of improvements which can be achieved for the transient behaviour. A nonlinear model-based approach is presented in this...