In real systems, the phenomena, such as pipe-wall viscoelasticity, unsteady friction or fluid structure interaction induce additional damping and dispersion of transient pressure waves than that defined by classical waterhammer. In this paper, unsteady friction models and viscoelastic damping models will be presented and a theoretical formulation of the viscoelastic damping in piping systems wi...

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 a fast convergence observer to estimate the vehicle velocity and the internal state of the friction model. The unknown parameters of the dynamic friction model are estimate...

In this paper, a software solution is presented for advanced friction modeling in metal forming processes, using a physically-based friction model. As input, the model requires the properties of the metal-lubricant combination used and the surface characteristics of the tooling and sheet material. As output, the friction coefficient is provided in both the boundary and mixed lubrication regime....

Friction characterization is a prerequisite for an accurate control of electromechanical systems. This paper considers the identification and control of friction in a high load torque DC motor to the end of achieving accurate tracking. In the first place, model-based feedforward controllers for friction compensation are considered. For this purpose, friction model structures ranging from the cl...

An experimental implementation of an output-feedback controller on a rotor dynamic system with set-valued friction is presented. The system exhibits coexisting stable/unstable equilibria and undesired friction-induced limit cycles. In the system, the friction and actuation are non-collocated, which prevents the application of standard friction compensation techniques. Therefore, an outputfeedba...

A robust adaptive compensation scheme is presented for compensation of asymmetric deadzone, dynamic friction and uncertainty in the direct-drive robot manipulator. Simple estimation laws are derived to build observers for estimation of deadzone and friction based on the LuGre friction model. A model-free RWCMAC controller to mimic the ideal control law is employed to overcome some shortcomings ...

Since no universal friction model exists and the practical measurement of friction is not straightforward, this paper presents an experimental method of identifying friction in mechatronic systems. Friction is perhaps the most important nonlinearity that is found in any mechatronic system of moving parts and influences the system in all regimes of operation. For the purpose of improving the per...

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, ...