WOLFRAM SYSTEMMODELER

Position

Forced movement of a flange according to a reference angle signal

Wolfram Language

In[1]:=
SystemModel["Modelica.Mechanics.Rotational.Sources.Position"]
Out[1]:=

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

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 (2)

useSupport

Value: false

Type: Boolean

Description: = true, if support flange enabled, otherwise implicitly grounded

f_crit

Value: 50

Type: Frequency (Hz)

Description: If exact=false, critical frequency of filter to filter input signal

Connectors (3)

flange

Type: Flange_b

Description: Flange of shaft

support

Type: Support

Description: Support/housing of component

phi_ref

Type: RealInput

Description: Reference angle of flange with respect to support as input signal

Used in Examples (2)

PlanarLoops_analytic

Modelica.Mechanics.MultiBody.Examples.Loops

Mechanism with three planar kinematic loops and one degree-of-freedom with analytic loop handling (with JointRRR joints)

MovingActuatedDrive

Modelica.Mechanics.MultiBody.Examples.Rotational3DEffects

Demonstrates usage of model Rotor1D mounted on a moving body