Brake based on Coulomb friction
Modelica Standard Library
The Rotational Brake (or Brake) component models a brake. A frictional torque acts between the housing and a flange and a controlled normal force presses the flange to the housing to increase friction.
The normal force applied to the braking surface is the product of a parameter, fnmax, and a normalized input signal, fnormalized.
When the absolute angular velocity is not zero, the friction torque is a function of the velocity dependent friction coefficient μ⁡w , the normal force, fn, and a geometric constant, cgeo, which takes into account the geometry of the device and the assumptions on the friction distributions.
The geometric constant is calculated as
where ri is the inner radius, ro is the outer radius, and N is the number of friction interfaces.
The positive part of the friction characteristic, μ⁡w,w≥0, is defined by the μpos parameter as a two-dimensional table (array) that specifies the sliding friction coefficients at given relative angular velocities. Each row has the form wrel,μ⁡wrel. The first column must be ordered, 0≤w1<w2<⋯<wm. To add rows, right-click on the value and select Edit Matrix Dimension. Only linear interpolation is supported.
Flange of left shaft
Flange of right shaft
Conditional Support Flange
Optional heat port
Real input; normalized force
Table of sliding friction coefficients at given relative velocities
peak⁢μpos1,2 is the static friction coefficient
Geometry constant containing friction distribution assumption
Maximum normal force
Use Heat Port
True (checked) means the heat port is enabled
use Support Flange
True (checked) means the support flange is enabled
The velocity reinitializes when ω≤ωsmall
Gain driving the relative motion between the friction elements to 0 when locked. This parameter should only be non-zero when using the model with fixed-step integration.
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.
1-D Mechanical Overview
Rotational Clutches and Brakes
Download Help Document
What kind of issue would you like to report? (Optional)