Sign Force

Constant force changing sign with speed

 Description The Sign Force component generates a constant force that changes sign with direction of movement. The parameter reg selects the equation for the force when the magnitude of the velocity is below ${v}_{0}$.
 Equations $f=-{f}_{\mathrm{flange}}={f}_{\mathrm{nom}}\left\{\begin{array}{cc}\frac{2}{1+\mathrm{exp}\left(-100\frac{v}{{v}_{0}}\right)}-1\phantom{\rule[-0.0ex]{20.0ex}{0.0ex}}& \mathrm{reg}=\mathrm{Exp}\\ \left\{\begin{array}{cc}1& {v}_{0}\le \left|v\right|\\ \mathrm{sin}\left(\frac{1}{2}\mathrm{\pi }\frac{v}{{v}_{0}}\right)& \mathrm{otherwise}\end{array}& \mathrm{reg}=\mathrm{Sine}\\ \left\{\begin{array}{cc}1& {v}_{0}\le \left|v\right|\\ \frac{v}{{v}_{0}}& \mathrm{otherwise}\end{array}\phantom{\rule[-0.0ex]{6.5ex}{0.0ex}}& \mathrm{reg}=\mathrm{Linear}\\ \left\{\begin{array}{cc}1& {v}_{0}\le \left|v\right|\\ \left(1-\mathrm{cos}\left(\frac{1}{2}\mathrm{\pi }\frac{v}{{v}_{0}}\right)\right)& \mathrm{otherwise}\end{array}& \mathrm{otherwise}\end{array}$ $s={s}_{\mathrm{flange}}-{s}_{\mathrm{support}}$ $v=\frac{ds}{\mathrm{dt}}$ $\mathbf{if}\mathrm{Use Support Flange}\mathbf{then}{f}_{\mathrm{support}}=-f$ $s={s}_{\mathrm{flange}}-\left\{\begin{array}{cc}{s}_{\mathrm{support}}& \mathrm{Use Support}\\ 0& \mathrm{otherwise}\end{array}$

Variables

 Name Units Description Modelica ID $s$ $m$ Distance between flange and support s $f$ $N$ Accelerating force acting at flange f $v$ $\frac{m}{s}$ Velocity of flange with respect to support v

Connections

 Name Description Modelica ID $\mathrm{flange}$ Flange of component flange $\mathrm{support}$ support

Parameters

 Name Default Units Description Modelica ID ${f}_{\mathrm{nom}}$ $N$ Nominal force f_nominal $\mathrm{reg}$ $\mathrm{Exp}$ Type of regularization reg ${v}_{0}$ $0.1$ $\frac{m}{s}$ Regularization below ${v}_{0}$ v0 Use Support Flange $\mathrm{false}$ True (checked) enables the support flange useSupport

 Modelica Standard Library 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.