Clutch based on Coulomb friction
Modelica Standard Library
The Rotational Clutch (or Clutch) component models a clutch controlled by an input signal. Two rotational flanges are pressed together via a normal force.
The normal force applied to the clutch 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.
Left flange of compliant 1-dim. rotational component
Right flange of compliant 1-dim. rotational component
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
Nominal value of φrel (used for scaling)
Prioritize φrel and wrel as states
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
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