Position
Forced movement of a flange according to a reference position
Library
Modelica/Mechanics/Translational/Sources
Description
The input signal s_ref defines the reference position in [m]. Flange flange is forced to move relative to the support connector according to this reference motion. According to parameter exact (default = false), this is done in the following way:
- exact=true
The reference position is treated exactly. This is only possible, if the input signal is defined by an analytical function which can be differentiated at least twice. If this prerequisite is fulfilled, the Modelica translator will differentiate the input signal twice in order to compute the reference acceleration of the flange. - exact=false
The reference position is filtered and the second derivative of the filtered curve is used to compute the reference acceleration of the flange. This second derivative is not computed by numerical differentiation but by an appropriate realization of the filter. For filtering, a second order Bessel filter is used. The critical frequency (also called cut-off frequency) of the filter is defined via parameter f_crit in [Hz]. This value should be selected in such a way that it is higher as the essential low frequencies in the signal.
The input signal can be provided from one of the signal generator blocks of the block library Modelica.Blocks.Sources.
Parameters
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_useSupport | useSupport | = true, if support flange enabled, otherwise implicitly grounded | Number | 0 |
mo_exact | exact | Is true/false for exact treatment/filtering of the input signal, respectively | Scalar | true |
mo_f_crit | f_crit | If exact=false, critical frequency of filter to filter input signal | Scalar | |
mo_w_crit | w_crit | Critical frequency | Scalar | |
mo_af | af | s coefficient of Bessel filter | Scalar | |
mo_bf | bf | s*s coefficient of Bessel filter | Scalar |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_s | s | s | Structure | |
mo_s/fixed | fixed | Cell of scalars | true | |
mo_s/start | start | Cell of scalars | ||
mo_v | v | v | Structure | |
mo_v/fixed | fixed | Cell of scalars | true | |
mo_v/start | start | Cell of scalars | ||
mo_a | a | a | Structure | |
mo_a/fixed | fixed | Cell of scalars | true | |
mo_a/start | start | Cell of scalars | ||
mo_s_ref | s_ref | s_ref | Structure | |
mo_s_ref/fixed | fixed | Cell of scalars | true | |
mo_s_ref/start | start | Cell of scalars |
Ports
| Name | Type | Description | IO Type | Number |
|---|---|---|---|---|
flange | implicit | Flange of component | output | 1 |
s_ref | implicit | Reference position of flange as input signal | input | 1 |
Port 3 | implicit | Support/housing of component | input | mo_useSupport |