The paper deals with the measurement, identification and compensation of low velocity friction in positioning systems. The introduced algorithms are based on a linearized friction model, which can easily be introduced in tracking control algorithms. The developed friction measurement and compensation methods can be implemented in simple industrial controller architectures, such as microcontroll...

Playability” is measured for variations in a bowed-string simulation model. The variations studied are (1) the effect of torsion waves, and (2) the effect of the choice of friction model. It is found that (1) elimination of torsion-wave simulation does not degrade playability, and (2) the more recently developed “plastic” bowedstring friction model, in which the frictional force is a function o...

In this paper, a disturbance observer based controller is proposed for the compensation of nonlinear friction in a servodrive system. The designed nonlinear controller uses the estimated system states (position, velocity) and disturbance to enhance tracking performance of the servodrive using high stiff gains for the compensation of the effects of nonlinear friction. The effectiveness of this d...

Friction exists in all machines having relative motion, and plays an important role in many servo mechanisms and simple pneumatic or hydraulic systems. In order to achieve high precision motion control, accurate friction modeling and effective compensation techniques have to be investigated. In this chapter, we shall present a systematic treatment of adaptive friction compensation techniques fr...

Rotation effects on MHD flow past an impulsively started vertical plate with variable mass diffusion is studied here. The governing equations involved in the present analysis are solved by the Laplace-transform technique. The velocity, concentration and skin friction are studied for different parameters like mass Grashof number, Schmidt number, magnetic field parameter, rotation parameter and t...

A second order sliding mode (SOSM) approach is proposed for orbital stabilization of a friction pendulum, operating under uncertain conditions. Only position measurements are assumed to be available. A SOSM velocity observer is developed and included into the closedloop system, driven by the quasihomogeneous controller that provides orbital stabilization of the pendulum. Performance issues of t...