Roller Detailed
Roller with slippage
Description
Usage
Equations
Connections
Parameters
Summary Variables
The Roller Detailed component models a pull roller with slippage.
The Roller component must be between two Span components. Using the provided 1D rotational flange (flange_c), the Roller component models a pull roller. Without any applied torque or setpoint velocity, the Roller models an idler roller.
The Roller Detailed component uses a series of spans internally to capture the changing nature of the web/roller interaction over the contact arc. Each span is subjected to friction on its nodes which are calculated from the span tension resultant fn and the coefficient of friction.
Consider one of the discretizing spans that cover 1n of the contact arc (where n is a component parameter).
Tension
tb−ta−μ⁢fn=0
Torque Transfer
τ=R⋅tb−ta
where
ta
Upstream tension
tb
Downstream tension
va
Upstream speed
vb
Downstream speed
τ
Friction torque applied to the roller by the span
R
Roller effective radius
ωr
Roller angular velocity
v0
Smoothing velocity value
Coefficient of Friction
The signed coefficient of friction is defined as
μ=μd⁢vrel+μc⁢tanh⁡vrelv0
vrel=R⁢ωr−va
See Span and Roller for further details.
Name
Modelica ID
framea
Left web 3-D connection point
frame_a
frameb
Right web 3-D connection point
frame_b
framec
Roller holder base frame; enabled when Use fixed base = false
frame_c
weba
Left (entry) web transfer information port (blue)
web_a
webb
Right (exit) web transfer information port (green)
web_b
flangec
Roller rotation flange
flange_c1
vout
Sensor output [1]
v_out
[1] Enabled when Use sensor is true.
Web Properties
Default
Use Default Properties (WP1)
true
When checked (true), web properties are defined by the closest Web Properties block found
useDefault
WP1
Name of the record containing the web properties (enabled when Use default properties = false)
wp
Settings Parameters
Units
Use alternative configuration
false
Choose between two possible solutions for the web/roll configuration
useAltConfig
Flip direction
Use this option when building web lines that go from right to left
flipDirection
Use fixed base
When checked (true), frame_c is disabled and the roller frame is fixed in the inertial coordinate frame (addition position and orientation parameters are enabled instead)
useFixedBase
Use sensor
When checked (true), a signal output is enabled for the web speed
useSensor
Output type
1
Select measured quantity. 1 means Web speed; 2 means Roller surface speed
sensorType
Velocity output unit
[1]
toUnitV
r
0,0
m
Location of frame_b with respect to ground. Available when Use fixed base = true
InitPos
θ
0
deg
Rotation about z-axis. Available when Use fixed base = true
InitAng
Roller
D
0.2
Diameter of roller
Use CAD
When checked (true), mass and inertia are defined from an externally attached CAD component or a rigid body component
useCAD
Di
Inner diameter of roller
L
1.2
Roller length
Use cylindrical geometry
When checked (true), roller inertia is calculated assuming a uniform cylindrical geometry
useCylindricalGeometry
ρ
2.7·103
kgm3
Roller density; enabled when using cylindrical geometry
rho_roll
kg
Roller mass; enabled when not using cylindrical geometry
J
0.005
kg⁢m2
Roller rotational inertia; enabled when not using cylindrical geometry
d
N⁢m⁢srad
Bearing viscous damping constant
Friction Parameters
μc
Coulomb coefficient of friction between web and roller
mu_c
μd
Viscous coefficient of friction between web and roller [1]
mu_d
1·10−4
ms
Smoothing function scale, i.e. tanh(v_rel/v0)
ndiv
5
Number of segments
nDiv
peak
Maximum friction force at zero sliding velocity is given by Peak.u_c [1]
vs
0.01
Stribeck sliding friction [1]
nDecay
Decay exponent [1]
P
Pa
Surface pressure (positive is suction)
Use constant CoF
When unchecked (false), a velocity-dependent formulation is used for the coefficient of friction.
useConstantCoF
[1] Enabled when Use constant CoF is false.
Frame
mf
Frame mass
m_frame
Jf
Frame inertia
J_frame
Add frame offset
When checked (true), frame connection point is placed at an offset w.r.t. the roll center
addFrameOffset
rf
Offset in the XY plane; enabled when Add frame offset is true
Visualization Parameters
Show roller
When checked (true), a visualization of the roller is created
showVisualization_roller
Transparent roller
When checked (true), the roller visualization is transparent
transparent_roller
Roller color
Blue
color_roller
Band color
Yellow
color_band
Band angle
20
band_angle
Show contact forces
When checked (true), arrows are added to visualize discretized web/roller contact forces (normal + friction)
showContactForce
Scale
100
mN
Force scale
forceScale
Color
Red
Force arrow color
forceColor
Transparency
Force arrow transparency
forceTransparent
Show sliding velocity arrows
When checked (true), an arrow is added to visualize local web/roller sliding velocity
showSlidingVelocity
s
Speed scale
speedScale
Green
Speed arrow color
speedColor
Speed arrow transparency
speedTransparent
Advanced Settings
Use effective radius
When checked (true), the roller radius is padded with half the web thickness
useEffectiveRadius
Summary variables provide easy access to quantities that maybe important in simulations to measure performance and other key metrics.
summary_WrapAngle
Wrap angle
summary_Length
Length of the web in contact with the roller
summary_Limit
0 to 1; 0 means tension limit is less than capstan limit or include slippage is true; 1 means tension limit exceeds capstan limit (web will slip)
summary_SlipVelocity
Slip velocity: web speed - roller surface speed
summary_SlipRatio
(roller surface speed - web speed)/(roller surface speed)
summary_RollerAngularVelocity
summary_WebSpeed
Web speed
summary_RollerSurfaceSpeed
Roller surface speed
summary_CoF
The traction/friction coefficient.
[1] Units are set in the corresponding Web Properties block (under the Summary variables section).
See Also
Rollers
Web Handling Library
Download Help Document