Translational Brake

Brake based on Coulomb friction

 Description The Translational Brake (or Brake) component models a brake. A frictional force acts between the housing and a flange and a controlled normal force presses the flange to the housing to increase friction. Normal Force The normal force applied to the braking surface is the product of a parameter, ${f}_{{n}_{\mathrm{max}}}$, and a normalized input signal, ${f}_{\mathrm{normalized}}$. ${f}_{n}={f}_{{n}_{\mathrm{max}}}{f}_{\mathrm{normalized}}\phantom{\rule[-0.0ex]{3.0ex}{0.0ex}}0\le {f}_{\mathrm{normalized}}\le 1$ Friction Force When the absolute velocity is not zero, the friction force is a function of the velocity dependent friction coefficient $\mathrm{\mu }\left(v\right)$ , the normal force, ${f}_{n}$, and a geometric constant, ${c}_{\mathrm{geo}}$, which takes into account the geometry of the device and the assumptions on the friction distributions. $\mathrm{\tau }={c}_{\mathrm{geo}}\mathrm{\mu }\left(v\right){f}_{n}$ The geometric constant is calculated as ${c}_{\mathrm{geo}}=N\frac{{r}_{o}+{r}_{i}}{2}$ where ${r}_{i}$ is the inner radius, ${r}_{o}$ is the outer radius, and $N$ is the number of friction interfaces. Friction Table The ${\mathrm{\mu }}_{\mathrm{pos}}$ parameter is a two-dimensional table (array) that specifies the sliding friction coefficients at given relative velocities. Each row has the form $\left[{v}_{\mathrm{rel}},\mathrm{\mu }\left({v}_{\mathrm{rel}}\right)\right]$. The first column must be ordered, $0\le {v}_{1}<{v}_{2}<\cdots <{v}_{m}$. To add rows, right-click on the value and select Edit Matrix Dimension.

Connections

 Name Description Modelica ID ${\mathrm{flange}}_{a}$ Flange of left shaft flange_a ${\mathrm{flange}}_{b}$ Flange of right shaft flange_b $\mathrm{support}$ support $\mathrm{heatPort}$ heatPort ${f}_{\mathrm{normalized}}$ Real input; normalized force f_normalized

Parameters

General Parameters

 Name Default Units Description Modelica ID ${\mathrm{\mu }}_{\mathrm{pos}}$ $\left[0.,0.5\right]$ $1$ Table of sliding friction coefficients at given relative velocities mue_pos $\mathrm{peak}$ $1$ $1$ $\mathrm{peak}{\mathrm{\mu }}_{\mathrm{pos}}\left[1,2\right]$ is the static friction coefficient peak ${c}_{\mathrm{geo}}$ $1$ $1$ Geometry constant containing friction distribution assumption cgeo ${\mathrm{fn}}_{\mathrm{max}}$ $1$ $N$ Maximum normal force fn_max Use Heat Port $\mathrm{false}$ True (checked) means heat port is enabled useHeatPort Use Support $\mathrm{false}$ True (checked) enables support flange useSupport

 Name Default Units Description Modelica ID ${v}_{\mathrm{small}}$ $0.001$ $\frac{m}{s}$ Relative velocity near to zero (see model info text) v_small