Rotational Friction
Purpose
Ideal rotational stick/slip friction
Library
Mechanical / Rotational / Components
Description
The Rotational Friction models any combination of static, Coulomb and viscous
friction between two flanges in a rotational system. While the component is stuck, it
exerts whatever force is necessary in order to maintain zero relative speed between
the flanges, up to the limit of the breakaway torque . When the breakaway
torque is exceeded, the flanges begin sliding against each other, and the
component exerts a torque that consists of the Coulomb friction torque
and a
speed-dependent viscous friction torque
.
The figure below shows the speed/torque characteristic and the state chart of the component. Note that the friction torque is opposed to the movement, hence the negative sign.
Parameters
- Breakaway friction torque
- The maximum magnitude of the stiction torque
, in Netwon meters
. Must be greater than or equal to zero.
- Coulomb friction torque
- The magnitude of the (constant) Coulomb friction
torque
, in Netwon meters
. Must be greater than or equal to zero and less than or equal to the breakaway friction torque.
- Viscous friction coefficient
- The proportionality coefficient
that determines the speed dependent viscous friction torque, in
.
Probe Signals
- Torque
- The transmitted torque
flowing from the unmarked to the marked flange, in Newton meters (Nm).
- Speed
- The angular speed
of the marked flange with respect to the unmarked flange, in
.
- State
- The internal state of the component: -1 sliding backward, 0 stuck, +1 sliding forward.