Modelica.Mechanics.Translational.Sources

Sources to drive 1D translational mechanical components

Information

This package contains ideal sources to drive 1D mechanical translational 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 position
Speed	Forced movement of a flange according to a reference speed
Accelerate	Forced movement of a flange according to an acceleration signal
Move	Forced movement of a flange according to a position, velocity and acceleration signal
Force	External force acting on a drive train element as input signal
Force2	Input signal acting as torque on two flanges
LinearSpeedDependentForce	Linear dependency of force versus speed
QuadraticSpeedDependentForce	Quadratic dependency of force versus speed
ConstantForce	Constant force, not dependent on speed
SignForce	Constant force changing sign with speed
ConstantSpeed	Constant speed, not dependent on force
ForceStep	Constant force, not dependent on speed
EddyCurrentForce	Simple model of a translational eddy current brake

Modelica.Mechanics.Translational.Sources.Position

Forced movement of a flange according to a reference position

Information

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:

1. 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.
2. 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.

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

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.Speed

Forced movement of a flange according to a reference speed

Information

The input signal v_ref defines the reference speed in [m/s]. 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:

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 speed is filtered and the first derivative of the filtered curve is used to compute the reference acceleration of the flange. This first 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.Translational.Interfaces.PartialElementaryOneFlangeAndSupport2 (Partial model for a component with one translational 1-dim. shaft flange and a support used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.Accelerate

Forced movement of a flange according to an acceleration signal

Information

The input signal a in [m/s2] moves the 1D translational flange connector flange with a predefined acceleration, i.e., the flange is forced to move relative to the support connector with this acceleration. The velocity and the position of the flange are also predefined and are determined by integration of the acceleration.

The acceleration "a(t)" can be provided from one of the signal generator blocks of the block library Modelica.Blocks.Source.

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

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.Move

Forced movement of a flange according to a position, velocity and acceleration signal

Information

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

u[1]: position of flange
u[2]: velocity of flange
u[3]: 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. 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 position = position(t) and set the velocity and the 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.Translational.Interfaces.PartialElementaryOneFlangeAndSupport2 (Partial model for a component with one translational 1-dim. shaft flange and a support used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.Force

External force acting on a drive train element as input signal

Information

The input signal "f" in [N] characterizes an external force which acts (with positive sign) at a flange, i.e., the component connected to the flange is driven by force f.

Input signal f can be provided from one of the signal generator blocks of Modelica.Blocks.Source.

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

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.Force2

Input signal acting as torque on two flanges

Information

The input signal "f" in [N] characterizes an external force which acts (with positive sign) at both flanges, i.e., the components connected to these flanges are driven by force f.

Input signal s can be provided from one of the signal generator blocks of Modelica.Blocks.Source.

Extends from Translational.Interfaces.PartialTwoFlanges (Component with two translational 1D flanges).

Connectors

Modelica.Mechanics.Translational.Sources.LinearSpeedDependentForce

Linear dependency of force versus speed

Information

Model of force, linearly dependent on velocity of flange.
Parameter ForceDirection chooses whether direction of force is the same in both directions of movement or not.

Extends from Modelica.Mechanics.Translational.Interfaces.PartialForce (Partial model of a force acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.QuadraticSpeedDependentForce

Quadratic dependency of force versus speed

Information

Model of force, quadratic dependent on velocity of flange.
Parameter ForceDirection chooses whether direction of force is the same in both directions of movement or not.

Extends from Modelica.Mechanics.Translational.Interfaces.PartialForce (Partial model of a force acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.ConstantForce

Constant force, not dependent on speed

Information

Model of constant force, not dependent on velocity of flange.

Please note:
Positive force accelerates in positive direction of movement, but brakes in reverse direction of movement.
Negative force brakes in positive direction of movement, but accelerates in reverse direction of movement.

Extends from Modelica.Mechanics.Translational.Interfaces.PartialForce (Partial model of a force acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.SignForce

Constant force changing sign with speed

Information

Model of constant force which changes sign with direction of movement.

Please note:
Positive force accelerates in both directions of movement.
Negative force brakes in both directions of movement.

Around zero speed regularization avoids numerical problems.

Extends from Modelica.Mechanics.Translational.Interfaces.PartialForce (Partial model of a force acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.ConstantSpeed

Constant speed, not dependent on force

Information

Model of fixed velocity of flange, not dependent on force.

Extends from Modelica.Mechanics.Translational.Interfaces.PartialForce (Partial model of a force acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.ForceStep

Constant force, not dependent on speed

Information

Model of a force step at time startTime. Positive force accelerates in positive direction of flange translation.

Extends from Modelica.Mechanics.Translational.Interfaces.PartialForce (Partial model of a force acting at the flange (accelerates the flange)).

Parameters

Connectors

Modelica.Mechanics.Translational.Sources.EddyCurrentForce

Simple model of a translational eddy current brake

Information

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

Thermal behaviour:
The resistance of the braking fin is influenced by the actual temperature Theatport, which in turn shifts the speed v_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 v_nominal at which the maximum torque occurs is adapted from reference temperature TRef to the operational temperature.

Extends from Modelica.Mechanics.Translational.Interfaces.PartialForce (Partial model of a force 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