Modelica.Mechanics.MultiBody.Interfaces

Information

This package contains connectors and partial models (i.e., models that are only used to build other models) of the MultiBody library.

Package Content

Name	Description
Frame	Coordinate system fixed to the component with one cut-force and cut-torque (no icon)
Frame_a	Coordinate system fixed to the component with one cut-force and cut-torque (filled rectangular icon)
Frame_b	Coordinate system fixed to the component with one cut-force and cut-torque (non-filled rectangular icon)
Frame_resolve	Coordinate system fixed to the component used to express in which coordinate system a vector is resolved (non-filled rectangular icon)
FlangeWithBearing	Connector consisting of 1-dim. rotational flange and its bearing frame
FlangeWithBearingAdaptor	Adaptor to allow direct connections to the sub-connectors of FlangeWithBearing
PartialTwoFrames	Base model for components providing two frame connectors + outer world + assert to guarantee that the component is connected
PartialTwoFramesDoubleSize	Base model for components providing two frame connectors + outer world + assert to guarantee that the component is connected (default icon size is factor 2 larger as usual)
PartialOneFrame_a	Base model for components providing one frame_a connector + outer world + assert to guarantee that the component is connected
PartialOneFrame_b	Base model for components providing one frame_b connector + outer world + assert to guarantee that the component is connected
PartialElementaryJoint	Base model for elementary joints (has two frames + outer world + assert to guarantee that the joint is connected)
PartialForce	Base model for force elements (provide frame_b.f and frame_b.t in subclasses)
PartialLineForce	Base model for line force elements
PartialAbsoluteSensor	Base model to measure an absolute frame variable
PartialRelativeSensor	Base model to measure a relative variable between two frames
PartialVisualizer	Base model for visualizers (has a frame_a on the left side + outer world + assert to guarantee that the component is connected)
ZeroPosition	Set absolute position vector of frame_resolve to a zero vector and the orientation object to a null rotation
partialGravityAcceleration
partialSurfaceCharacteristic
partialColorMap	Interface for a function returning a color map

Modelica.Mechanics.MultiBody.Interfaces.Frame

Information

Basic definition of a coordinate system that is fixed to a mechanical component. In the origin of the coordinate system the cut-force and the cut-torque is acting. This component has no icon definition and is only used by inheritance from frame connectors to define different icons.

Contents

Name	Description
r_0[3]	Position vector from world frame to the connector frame origin, resolved in world frame [m]
R	Orientation object to rotate the world frame into the connector frame
f[3]	Cut-force resolved in connector frame [N]
t[3]	Cut-torque resolved in connector frame [N.m]

Modelica.Mechanics.MultiBody.Interfaces.Frame_a

Information

Basic definition of a coordinate system that is fixed to a mechanical component. In the origin of the coordinate system the cut-force and the cut-torque is acting. This component has a filled rectangular icon.

Contents

Name	Description
r_0[3]	Position vector from world frame to the connector frame origin, resolved in world frame [m]
R	Orientation object to rotate the world frame into the connector frame
f[3]	Cut-force resolved in connector frame [N]
t[3]	Cut-torque resolved in connector frame [N.m]

Modelica.Mechanics.MultiBody.Interfaces.Frame_b

Information

Basic definition of a coordinate system that is fixed to a mechanical component. In the origin of the coordinate system the cut-force and the cut-torque is acting. This component has a non-filled rectangular icon.

Contents

Name	Description
r_0[3]	Position vector from world frame to the connector frame origin, resolved in world frame [m]
R	Orientation object to rotate the world frame into the connector frame
f[3]	Cut-force resolved in connector frame [N]
t[3]	Cut-torque resolved in connector frame [N.m]

Modelica.Mechanics.MultiBody.Interfaces.Frame_resolve

Information

Basic definition of a coordinate system that is fixed to a mechanical component. In the origin of the coordinate system the cut-force and the cut-torque is acting. This coordinate system is used to express in which coordinate system a vector is resolved. A component that uses a Frame_resolve connector has to set the cut-force and cut-torque of this frame to zero. When connecting from a Frame_resolve connector to another frame connector, by default the connecting line has line style "dotted". This component has a non-filled rectangular icon.

Contents

Name	Description
r_0[3]	Position vector from world frame to the connector frame origin, resolved in world frame [m]
R	Orientation object to rotate the world frame into the connector frame
f[3]	Cut-force resolved in connector frame [N]
t[3]	Cut-torque resolved in connector frame [N.m]

Modelica.Mechanics.MultiBody.Interfaces.FlangeWithBearing

Information

This hierarchical connector models a 1-dim. rotational flange connector and its optional bearing defined by a 3-dim. frame connector. If a connection to the subconnectors should be clearly visible, connect first an instance of FlangeWithBearingAdaptor to the FlangeWithBearing connector.

Parameters

Name	Description
includeBearingConnector	= true, if bearing frame connector is present, otherwise not present

Contents

Name	Description
includeBearingConnector	= true, if bearing frame connector is present, otherwise not present
flange	1-dim. rotational flange
bearingFrame	3-dim. frame in which the 1-dim. shaft is mounted

Modelica.Mechanics.MultiBody.Interfaces.FlangeWithBearingAdaptor

Information

Adaptor object to make a more visible connection to the flange and frame subconnectors of a FlangeWithBearing connector.

Parameters

Name	Description
includeBearingConnector	= true, if bearing frame connector is present, otherwise not present

Connectors

Name	Description
flangeAndFrame	Compound connector consisting of 1-dim. rotational flange and 3-dim. frame mounting
flange	1-dim. rotational flange
frame	3-dim. frame in which the 1-dim. shaft is mounted

Modelica.Mechanics.MultiBody.Interfaces.PartialTwoFrames

Information

This partial model provides two frame connectors, access to the world object and an assert to check that both frame connectors are connected. Therefore, inherit from this partial model if the two frame connectors are needed and if the two frame connectors should be connected for a correct model.

Connectors

Name	Description
frame_a	Coordinate system fixed to the component with one cut-force and cut-torque
frame_b	Coordinate system fixed to the component with one cut-force and cut-torque

Modelica.Mechanics.MultiBody.Interfaces.PartialTwoFramesDoubleSize

Information

This partial model provides two frame connectors, access to the world object and an assert to check that both frame connectors are connected. Therefore, inherit from this partial model if the two frame connectors are needed and if the two frame connectors should be connected for a correct model.

When dragging "PartialTwoFrames", the default size is a factor of two larger as usual. This partial model is used by the Joint.Assemblies joint aggregation models.

Connectors

Name	Description
frame_a	Coordinate system fixed to the component with one cut-force and cut-torque
frame_b	Coordinate system fixed to the component with one cut-force and cut-torque

Modelica.Mechanics.MultiBody.Interfaces.PartialOneFrame_a

Information

This partial model provides one frame_a connector, access to the world object and an assert to check that the frame_a connector is connected. Therefore, inherit from this partial model if the frame_a connector is needed and if this connector should be connected for a correct model.

Connectors

Name	Description
frame_a	Coordinate system fixed to the component with one cut-force and cut-torque

Modelica.Mechanics.MultiBody.Interfaces.PartialOneFrame_b

Information

This partial model provides one frame_b connector, access to the world object and an assert to check that the frame_b connector is connected. Therefore, inherit from this partial model if the frame_b connector is needed and if this connector should be connected for a correct model.

Connectors

Name	Description
frame_b	Coordinate system fixed to the component with one cut-force and cut-torque

Modelica.Mechanics.MultiBody.Interfaces.PartialElementaryJoint

Information

All elementary joints should inherit from this base model, i.e., joints that are directly defined by equations, provided they compute either the rotation object of frame_b from the rotation object of frame_a and from relative quantities (or vice versa), or there is a constraint equation between the rotation objects of the two frames. In other cases, a joint object should inherit from Interfaces.PartialTwoFrames (e.g., joint Spherical, because there is no constraint between the rotation objects of frame_a and frame_b or joint Cylindrical because it is not an elementary joint).

This partial model provides two frame connectors, a "Connections.branch" between frame_a and frame_b, access to the world object and an assert to check that both frame connectors are connected.

Connectors

Name	Description
frame_a	Coordinate system fixed to the joint with one cut-force and cut-torque
frame_b	Coordinate system fixed to the joint with one cut-force and cut-torque

Modelica.Mechanics.MultiBody.Interfaces.PartialForce

Information

All 3-dimensional force and torque elements should be based on this superclass. This model defines frame_a and frame_b, computes the relative translation and rotation between the two frames and calculates the cut-force and cut-torque at frame_a by a force and torque balance from the cut-force and cut-torque at frame_b. As a result, in a subclass, only the relationship between the cut-force and cut-torque at frame_b has to be defined as a function of the following relative quantities:

  r_rel_b[3]: Position vector from origin of frame_a to origin
              of frame_b, resolved in frame_b
  R_rel     : Relative orientation object to rotate from frame_a to frame_b

Assume that force f = {100,0,0} should be applied on the body to which this force element is attached at frame_b, then the definition should be:

   model Constant_x_Force
      extends Modelica.Mechanics.MultiBody.Interfaces.PartialForce;
   equation
      frame_b.f = {-100, 0, 0};
      frame_b.t = zeros(3);
   end Constant_x_Force;

Note, that frame_b.f and frame_b.t are flow variables and therefore the negative value of frame_b.f and frame_b.t is acting at the part to which this force element is connected.

Connectors

Name	Description
frame_a	Coordinate system fixed to the joint with one cut-force and cut-torque
frame_b	Coordinate system fixed to the joint with one cut-force and cut-torque

Modelica.Mechanics.MultiBody.Interfaces.PartialLineForce

Information

All line force elements should be based on this base model. This model defines frame_a and frame_b, computes the relative distance s and provides the force and torque balance of the cut-forces and cut-torques at frame_a and frame_b, respectively. In sub-models, only the line force f, acting at frame_b on the line from frame_a to frame_b, as a function of the relative distance s and its derivative der(s) has to be defined. Example:

   model Spring
      parameter Real c "spring constant",
      parameter Real s_unstretched "unstretched spring length";
      extends Modelica.Mechanics.MultiBody.Interfaces.PartialLineForce;
   equation
      f = c*(s-s_unstretched);
   end Spring;

Parameters

Name	Description
Advanced
s_small	Prevent zero-division if relative distance s=0 [m]
If enabled, can give wrong results, see MultiBody.UsersGuide.Tutorial.ConnectionOfLineForces
fixedRotationAtFrame_a	=true, if rotation frame_a.R is fixed (to directly connect line forces)
fixedRotationAtFrame_b	=true, if rotation frame_b.R is fixed (to directly connect line forces)

Connectors

Name	Description
frame_a	Coordinate system fixed to the force element with one cut-force and cut-torque
frame_b	Coordinate system fixed to the force element with one cut-force and cut-torque

Modelica.Mechanics.MultiBody.Interfaces.PartialAbsoluteSensor

Information

This is the base class of a 3-dim. mechanics component with one frame and one output port in order to measure an absolute quantity in the frame connector and to provide the measured signal as output for further processing with the blocks of package Modelica.Blocks.

Parameters

Name	Description
n_out	Number of output signals

Connectors

Name	Description
frame_a	Coordinate system from which absolute quantities are provided as output signals
y[n_out]	Measured data as signal vector

Modelica.Mechanics.MultiBody.Interfaces.PartialRelativeSensor

Information

This is a base class for 3-dim. mechanical components with two frames and one output port in order to measure relative quantities between the two frames or the cut-forces/torques in the frame and to provide the measured signals as output for further processing with the blocks of package Modelica.Blocks.

Parameters

Name	Description
n_out	Number of output signals

Connectors

Name	Description
frame_a	Coordinate system a
frame_b	Coordinate system b
y[n_out]	Measured data as signal vector

Modelica.Mechanics.MultiBody.Interfaces.PartialVisualizer

Information

This partial model provides one frame_a connector, access to the world object and an assert to check that the frame_a connector is connected. It is used by inheritance from all visualizer objects.

Connectors

Name	Description
frame_a	Coordinate system in which visualization data is resolved

Modelica.Mechanics.MultiBody.Interfaces.ZeroPosition

Information

Connectors

Name	Description
frame_resolve

Modelica.Mechanics.MultiBody.Interfaces.partialGravityAcceleration

Information

This partial function defines the interface to the gravity function used in the World object. All gravity field functions must inherit from this function. The input to the function is the absolute position vector of a point in the gravity field, whereas the output is the gravity acceleration at this point, resolved in the world frame.

Inputs

Name	Description
r[3]	Position vector from world frame to actual point, resolved in world frame [m]

Outputs

Name	Description
gravity[3]	Gravity acceleration at position r, resolved in world frame [m/s2]

Modelica.Mechanics.MultiBody.Interfaces.partialSurfaceCharacteristic

Information

Inputs

Name	Description
nu	Number of points in u-Dimension
nv	Number of points in v-Dimension
multiColoredSurface	= true: Color is defined for each surface point

Outputs

Name	Description
X[nu, nv]	[nu,nv] positions of points in x-Direction resolved in surface frame [m]
Y[nu, nv]	[nu,nv] positions of points in y-Direction resolved in surface frame [m]
Z[nu, nv]	[nu,nv] positions of points in z-Direction resolved in surface frame [m]
C[if multiColoredSurface then nu else 0, if multiColoredSurface then nv else 0, 3]	[nu,nv,3] Color array, defining the color for each surface point

Modelica.Mechanics.MultiBody.Interfaces.partialColorMap

Information

This partial function defines the interface of a function that returns a color map. Predefined color map functions are defined in package Modelica.Mechanics.MultiBody.Visualizers.Colors.ColorMaps.

Inputs

Name	Description
n_colors	Number of colors in the color map

Outputs

Name	Description
colorMap[n_colors, 3]	Color map to map a scalar to a color