The Friction component models friction losses.

For stability, at low speeds the torque is linear with respect to velocity. At higher speeds, a power law is used.

Fig. 1: Friction loss torque versus angular velocity for $p_{\mathrm{\omega }}\=2$

To neglect friction losses, set $P_{\mathrm{ref}}\=0$ (this is the default).

$\mathrm{\tau }\=\{\begin{array}{cc}0& P_{\mathrm{ref}}\le 0\\ -{\mathrm{\tau }}_{\mathrm{ref}}{\left(\frac{\mathrm{\omega }}{{\mathrm{\omega }}_{\mathrm{ref}}}\right)}^{p_{\mathrm{\omega }}}& {\mathrm{\omega }}_{\mathrm{linear}}\le \mathrm{\omega }\\ {\mathrm{\tau }}_{\mathrm{ref}}{\left(-\frac{\mathrm{\omega }}{{\mathrm{\omega }}_{\mathrm{ref}}}\right)}^{p_{\mathrm{\omega }}}& \mathrm{\omega }\le -{\mathrm{\omega }}_{\mathrm{linear}}\\ -\frac{{\mathrm{\tau }}_{\mathrm{linear}}\mathrm{\omega }}{{\mathrm{\omega }}_{\mathrm{linear}}}& \mathrm{otherwise}\end{array}$

$\mathrm{\tau }\={\mathrm{\tau }}_{\mathrm{support}}\=-{\mathrm{\tau }}_{\mathrm{flange}}$

${\mathrm{\tau }}_{\mathrm{ref}}\=\frac{P_{\mathrm{ref}}}{{\mathrm{\omega }}_{\mathrm{ref}}}$

$\mathrm{\phi }\={\mathrm{\phi }}_{\mathrm{flange}}-{\mathrm{\phi }}_{\mathrm{support}}$

$\mathrm{\omega }\=\stackrel{\.}{\mathrm{\phi }}$

${\mathrm{\omega }}_{\mathrm{linear}}\=0.001{\mathrm{\omega }}_{\mathrm{ref}}$

$\mathrm{lossPower}\=-\mathrm{\tau }\mathrm{\omega }$

The component described in this topic is from the Modelica Standard Library. To view the original documentation, which includes author and copyright information, click here.