Rotational Friction (Controlled)

Purpose

Generate variable rotational friction

Library

Mechanical / Rotational / Components

Description

../../_images/controlledrotationalfriction.svg

The Controlled Rotational Friction component models the friction between two flanges in a rotational system. It maintains zero relative velocity between the flanges up to the limit of the breakaway torque \(\tau_{\mathrm{brk}}\). When the breakaway torque is exceeded, the flanges slide against each other and the component generates the Coulomb friction torque \(\tau_{\mathrm{C}}\).

This component does not include viscous friction.

The breakaway torque \(\tau_{\mathrm{brk}}\) is determined by the control signal and must always be greater than or equal to zero. The magnitude of the Coulomb friction \(\tau_{\mathrm{C}}\) is proportional to the control signal.

Parameters

Relative Coulomb friction torque

The coefficient \(c_C\) determines the magnitude of the Coulomb friction torque \(\tau_{\mathrm{C}}=c_C\cdot \tau_{\mathrm{brk}}\) and must be between zero and one.

Probe Signals

Torque

The transmitted torque \(\tau\) flowing from the unmarked to the marked flange, in newton-meters \((\mathrm{Nm})\).

Speed

The angular speed \(\omega\) of the marked flange with respect to the unmarked flange, in \(\left( \frac{\mathrm{rad}}{\mathrm{s}} \right)\).

State

The internal state of the component: -1 sliding backward, 0 stuck, +1 sliding forward.