Modelica.Mechanics.Rotational.Sources

Sources to drive 1D rotational mechanical components

Information

This package contains ideal sources to drive 1D mechanical rotational drive trains.

Extends from Modelica.Icons.SourcesPackage (Icon for packages containing sources).

Package Content

Name	Description
Position	Forced movement of a flange according to a reference angle signal
Speed	Forced movement of a flange according to a reference angular velocity signal
Accelerate	Forced movement of a flange according to an acceleration signal
Move	Forced movement of a flange according to an angle, speed and angular acceleration signal
Torque	Input signal acting as external torque on a flange
Torque2	Input signal acting as torque on two flanges
LinearSpeedDependentTorque	Linear dependency of torque versus speed
QuadraticSpeedDependentTorque	Quadratic dependency of torque versus speed
ConstantTorque	Constant torque, not dependent on speed
SignTorque	Constant torque changing sign with speed
ConstantSpeed	Constant speed, not dependent on torque
TorqueStep	Constant torque, not dependent on speed
EddyCurrentTorque	Simple model of a rotational eddy current brake

Modelica.Mechanics.Rotational.Sources.Position

Forced movement of a flange according to a reference angle signal

Information

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.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialElementaryOneFlangeAndSupport2 (Partial model for a component with one rotational 1-dim. shaft flange and a support used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.Speed

Forced movement of a flange according to a reference angular velocity signal

Information

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

1. exact=true
   The reference speed is treated exactly. This is only possible, if the input signal is defined by an analytical function which can be differentiated at least once. If this prerequisite is fulfilled, the Modelica translator will differentiate the input signal once 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 first order 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.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialElementaryOneFlangeAndSupport2 (Partial model for a component with one rotational 1-dim. shaft flange and a support used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.Accelerate

Forced movement of a flange according to an acceleration signal

Information

The input signal a defines an angular acceleration in [rad/s2]. Flange flange is forced to move relative to flange support with this acceleration. The angular velocity w and the rotation angle phi of the flange are automatically determined by integration of the acceleration.

The input signal can be provided from one of the signal generator blocks of the block library Modelica.Blocks.Sources.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialElementaryOneFlangeAndSupport2 (Partial model for a component with one rotational 1-dim. shaft flange and a support used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.Move

Forced movement of a flange according to an angle, speed and angular acceleration signal

Information

Flange flange is forced to move relative to flange support with a predefined motion according to the input signals:

u[1]: angle of flange
u[2]: angular velocity of flange
u[3]: angular acceleration of flange

The user has to guarantee that the input signals are consistent to each other, i.e., that u[2] is the derivative of u[1] and that u[3] is the derivative of u[2]. There are, however, also applications where by purpose these conditions do not hold. For example, if only the position dependent terms of a mechanical system shall be calculated, one may provide angle = angle(t) and set the angular velocity and the angular acceleration to zero.

The input signals can be provided from one of the signal generator blocks of the block library Modelica.Blocks.Sources.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialElementaryOneFlangeAndSupport2 (Partial model for a component with one rotational 1-dim. shaft flange and a support used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.Torque

Input signal acting as external torque on a flange

Information

The input signal tau defines an external torque in [Nm] which acts (with negative sign) at a flange connector, i.e., the component connected to this flange is driven by torque tau.

The input signal can be provided from one of the signal generator blocks of Modelica.Blocks.Sources.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialElementaryOneFlangeAndSupport2 (Partial model for a component with one rotational 1-dim. shaft flange and a support used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.Torque2

Input signal acting as torque on two flanges

Information

The input signal tau defines an external torque in [Nm] which acts at both flange connectors, i.e., the components connected to these flanges are driven by torque tau.

The input signal can be provided from one of the signal generator blocks of Modelica.Blocks.Sources.

Extends from Rotational.Interfaces.PartialTwoFlanges (Partial model for a component with two rotational 1-dim. shaft flanges).

Connectors

Modelica.Mechanics.Rotational.Sources.LinearSpeedDependentTorque

Linear dependency of torque versus speed

Information

Model of torque, linearly dependent on angular velocity of flange.
Parameter TorqueDirection chooses whether direction of torque is the same in both directions of rotation or not.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialTorque (Partial model of a torque acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.QuadraticSpeedDependentTorque

Quadratic dependency of torque versus speed

Information

Model of torque, quadratic dependent on angular velocity of flange.
Parameter TorqueDirection chooses whether direction of torque is the same in both directions of rotation or not.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialTorque (Partial model of a torque acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.ConstantTorque

Constant torque, not dependent on speed

Information

Model of constant torque, not dependent on angular velocity of flange.

Please note:
Positive torque accelerates in positive direction of rotation, but brakes in reverse direction of rotation.
Negative torque brakes in positive direction of rotation, but accelerates in reverse direction of rotation.

Extends from Rotational.Interfaces.PartialTorque (Partial model of a torque acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.SignTorque

Constant torque changing sign with speed

Information

Model of constant torque which changes sign with direction of rotation.

Please note:
Positive torque accelerates in both directions of rotation.
Negative torque brakes in both directions of rotation.

Around zero speed regularization avoids numerical problems.

Extends from Rotational.Interfaces.PartialTorque (Partial model of a torque acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.ConstantSpeed

Constant speed, not dependent on torque

Information

Model of fixed angular velocity of flange, not dependent on torque.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialTorque (Partial model of a torque acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.TorqueStep

Constant torque, not dependent on speed

Information

Model of a torque step at time startTime. Positive torque accelerates in positive direction of flange rotation.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialTorque (Partial model of a torque acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Rotational.Sources.EddyCurrentTorque

Simple model of a rotational eddy current brake

Information

This is a simple model of a rotational eddy current brake. The torque versus speed characteristic is defined by Kloss' equation.

Thermal behaviour:
The resistance of the braking disc is influenced by the actual temperature Theatport, which in turn shifts the speed w_nominal at which the (unchanged) maximum torque occurs.
If the heatPort is not used (useHeatPort = false), the operational temperature remains at the given temperature T.
However, the speed w_nominal at which the maximum torque occurs is adapted from reference temperature TRef to the operational temperature.

Extends from Modelica.Mechanics.Rotational.Interfaces.PartialTorque (Partial model of a torque acting at the flange (accelerates the flange)), Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPort (Partial model to include a conditional HeatPort in order to dissipate losses, used for textual modeling, i.e., for elementary models).

Parameters

Connectors