Position

Forced movement of a flange according to a reference angle signal

    Position

Library

Modelica/Mechanics/Rotational/Sources

Description

The input signal phi_ref defines the reference angle in [rad]. Flange flange is forced to move according to this reference motion relative to flange support. According to parameter exact (default = false), this is done in the following way:

  1. exact=true
    The reference angle 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.
  2. exact=false
    The reference angle 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

Position_0

NameLabelDescriptionData TypeValid Values

mo_useSupport

useSupport

= true, if support flange enabled, otherwise implicitly grounded

Number

0
1

mo_exact

exact

Is true/false for exact treatment/filtering of the input signal, respectively

Scalar

true
false

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

Position_1

NameLabelDescriptionData TypeValid Values

mo_phi

phi

phi

Structure

mo_phi/fixed

fixed

Cell of scalars

true
false

mo_phi/start

start

Cell of scalars

mo_w

w

w

Structure

mo_w/fixed

fixed

Cell of scalars

true
false

mo_w/start

start

Cell of scalars

mo_a

a

a

Structure

mo_a/fixed

fixed

Cell of scalars

true
false

mo_a/start

start

Cell of scalars

mo_phi_ref

phi_ref

phi_ref

Structure

mo_phi_ref/fixed

fixed

Cell of scalars

true
false

mo_phi_ref/start

start

Cell of scalars

Ports

NameTypeDescriptionIO TypeNumber

flange

implicit

Flange of shaft

output

1

phi_ref

implicit

Reference angle of flange with respect to support as input signal

input

1

Port 3

implicit

Support/housing of component

input

mo_useSupport