RollingResistance
Resistance of a rolling wheel
Library
Modelica/Mechanics/Translational/Components
Description
Simplified model of the resistance of a rolling wheel,dependent on vertical wheel load (due to gravity, i.e. static only),inclination and rolling resistance coefficient:
flange.f = Cr * fWeight * cos(alpha)
The rolling resistance coefficient Cr is either constant(given by the parameter CrConstant)or prescribed by the input cr.
The inclination is either constant (parameter inclinationConstant)or prescribed by the input inclination.This corresponds to the road rise over running distance of 100 m which,in general, is written as a percentage and is equal to tan(α).For example for a road rising by 10 m over 100 m thegrade = 10 % and, thus, the inclination is 0.1.Positive inclination means driving uphill, negative inclination meansdriving downhill, in case of positive vehicle velocity.
Note
The rolling resistance is independent of velocity here,but changes its direction with the direction of velocity.To avoid numerical problems around zero velocity, the rollingresistance is regularized accordingly within [-v0, v0].Therefore static friction at vehicle's standstillis not taken into account.
Parameters
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_useSupport | useSupport | = true, if support flange enabled, otherwise implicitly grounded | Number | 0 |
mo_fWeight | fWeight | Wheel load due to gravity | Scalar | |
mo_useCrInput | useCrInput | Enable signal input for Cr | Number | 0 |
mo_CrConstant | CrConstant | Constant rolling resistance coefficient | Scalar | |
mo_useInclinationInput | useInclinationInput | Enable signal input for inclination | Number | 0 |
mo_inclinationConstant | inclinationConstant | Constant inclination = tan(angle) | Scalar | |
mo_reg | reg | Type of regularization | Structure | |
mo_reg/choice1 | Modelica.Blocks.Types.Regularization.Exp | Number | 0 | |
mo_reg/choice2 | Modelica.Blocks.Types.Regularization.Sine | Number | 0 | |
mo_reg/choice3 | Modelica.Blocks.Types.Regularization.Linear | Number | 0 | |
mo_reg/choice4 | Modelica.Blocks.Types.Regularization.Cosine | Number | 0 | |
mo_v0 | v0 | Regularization below v0 | Scalar |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo__nmodifiers | Number of Modifiers | Specifies the number of modifiers | Number | |
mo__modifiers | Modifiers | Add new modifier | Structure | |
mo__modifiers/varname | Variable name | Cell of strings | 's' | |
mo__modifiers/attribute | Attribute | Cell of strings | 'start' | |
mo__modifiers/value | Value |
Ports
| Name | Type | Description | IO Type | Number |
|---|---|---|---|---|
flange | implicit | Flange of component | output | 1 |
Port 2 | implicit | Support/housing of component | input | mo_useSupport |
Port 3 | implicit | Inclination=tan(angle) | input | mo_useInclinationInput |
Port 4 | implicit | Rolling resistance coefficient | input | mo_useCrInput |