Translational Speed

Forced movement of a flange according to a reference speed

 Description The Translational Speed (or Speed) component generates a forced translational speed according to an input signal, ${v}_{\mathrm{ref}}$ The $\mathrm{Exact}$ boolean parameter determine how ${v}_{\mathrm{ref}}$ is used: When $\mathrm{Exact}$ is true, ${v}_{\mathrm{ref}}$ is used as-is. The input signal must be differentiable. When $\mathrm{Exact}$ is false (the default), ${v}_{\mathrm{ref}}$ is filtered and the derivative of the filtered curve is used to compute the reference acceleration of the flange. This derivative is not computed by numerical differentiation but rather by a first-order filter. The critical frequency (cut-off frequency) of the filter is defined by the parameter ${f}_{\mathrm{crit}}$, which should be higher than the essential low frequencies in the signal. The Use Support Flange boolean parameter enables a support flange on the housing. When true (checked) the support flange must be connected in the drawing. When false the component is internally fixed to ground.
 Equations $\left\{\begin{array}{cc}\left\{a=0,v={v}_{\mathrm{ref}}\right\}& \mathrm{Exact}\\ \left\{a=\left({v}_{\mathrm{ref}}-v\right){v}_{\mathrm{crit}},a=\stackrel{.}{v}\right\}& \mathrm{otherwise}\end{array}$ ${w}_{\mathrm{crit}}=2\mathrm{\pi }{f}_{\mathrm{crit}}$ $v=\stackrel{.}{s}$ $\mathbf{if}\mathrm{Use Support Flange}\mathbf{then}{f}_{\mathrm{support}}=-f$ $s={s}_{\mathrm{flange}}-\left\{\begin{array}{cc}{s}_{\mathrm{support}}& \mathrm{Use Support}\\ 0& \mathrm{otherwise}\end{array}$

Variables

 Name Units Description Modelica ID $a$ $\frac{m}{{s}^{2}}$ Acceleration of flange with respect to support a ${f}_{\mathrm{support}}$ $N$ Force acting at support support.f $s$ $m$ Distance between flange and support s ${s}_{\mathrm{flange}}$ $m$ Position of flange flange.s ${s}_{\mathrm{support}}$ $m$ Position of support support.s $v$ $\frac{m}{s}$ Velocity of flange with respect to support v

Connections

 Name Description Modelica ID $\mathrm{flange}$ Flange of component flange $\mathrm{support}$ support ${v}_{\mathrm{ref}}$ Real input; reference speed in $\frac{m}{s}$ v_ref

Parameters

 Name Default Units Description Modelica ID Exact $\mathrm{false}$ True (checked) means the reference position is treated exactly exact ${f}_{\mathrm{crit}}$ $50$ $\mathrm{Hz}$ Critical frequency of input signal when exact is set to false f_crit Use Support Flange $\mathrm{false}$ True (checked) enables 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.