Modelica.Mechanics.Translational.Interfaces.Flange_b

Information

The following variables are transported through this connector:

  s: Absolute position of the flange in [m]. A positive translation
     means that the flange is translated along the flange axis.
  f: Cut-force in direction of the flange axis in [N].

Modelica definition

connector Flange_b 
  "right 1D translational flange (flange axis directed OUT OF cut plane)"
   
  SI.Position s "absolute position of flange";
  flow SI.Force f "cut force directed into flange";
end Flange_b;

Modelica.Mechanics.Translational.Interfaces

Modelica.Mechanics.Translational.Interfaces.Rigid

Information

This is a 1D translational component with two rigidly connected flanges. The distance between the left and the right flange is always constant, i. e. L. The forces at the right and left flange can be different. It is used e.g. to built up sliding masses.

Release Notes:

• First Version from August 26, 1999 by P. Beater (based on Rotational.Rigid)

Parameters

Name	Default	Description
L	0	length of component from left flange to right flange (= flange_b.s - flange_a.s) [m]

Modelica definition

partial model Rigid 
  "Rigid connection of two translational 1D flanges " 
  SI.Position s 
    "absolute position of center of component (s = flange_a.s + L/2 = flange_b.s - L/2)"
    ;
  parameter SI.Length L=0 
    "length of component from left flange to right flange (= flange_b.s - flange_a.s)"
    ;
  Flange_a flange_a 
    "(left) driving flange (flange axis directed INTO cut plane, i. e. from left to right)"
    ;
  Flange_b flange_b 
    "(right) driven flange (flange axis directed OUT OF cut plane, i. e. from right to left)"
    ;
equation 
  flange_a.s = s - L/2;
  flange_b.s = s + L/2;
end Rigid;

Modelica.Mechanics.Translational.Interfaces.FrictionBase

Information

Release Notes:

• Version from January 5, 2000 by P. Beater (based on Translational.FrictionBase from Martin Otter)

Parameters

Name	Default	Description
L	0	length of component from left flange to right flange (= flange_b.s - flange_a.s) [m]
smax	25	right stop for (right end of) sliding mass [m]
smin	-25	left stop for (left end of) sliding mass [m]
v_small	1e-3	Relative velocity near to zero (see model info text) [m/s]

Modelica definition

partial model FrictionBase "Base class of Coulomb friction elements" 
  extends Rigid;
  parameter SI.Position smax=25 "right stop for (right end of) sliding mass";
  parameter SI.Position smin=-25 "left stop for (left end of) sliding mass";
  parameter SI.Velocity v_small=1e-3 
    "Relative velocity near to zero (see model info text)";
  
  
    // Equations to define the following variables have to be defined in subclasses
  SI.Velocity v_relfric "Relative velocity between frictional surfaces";
  SI.Acceleration a_relfric 
    "Relative acceleration between frictional surfaces";
  SI.Force f 
    "Friction force (positive, if directed in opposite direction of v_rel)";
  SI.Force f0 "Friction force for v=0 and forward sliding";
  SI.Force f0_max "Maximum friction force for v=0 and locked";
  Boolean free "true, if frictional element is not active";
  
  // Equations to define the following variables are given in this class
  Real sa "Path parameter of friction characteristic f = f(a_relfric)";
  
  Boolean startForward 
    "true, if v_rel=0 and start of forward sliding or v_rel > v_small";
  Boolean startBackward 
    "true, if v_rel=0 and start of backward sliding or v_rel < -v_small";
  Boolean locked "true, if v_rel=0 and not sliding";
  
  constant Integer Unknown=3 "Value of mode is not known";
  constant Integer Free=2 "Element is not active";
  constant Integer Forward=1 "v_rel > 0 (forward sliding)";
  constant Integer Stuck=0 
    "v_rel = 0 (forward sliding, locked or backward sliding)";
  constant Integer Backward=-1 "v_rel < 0 (backward sliding)";
  Integer mode(
    final min=Backward, 
    final max=Unknown, 
    start=Unknown);
equation 
  /* Friction characteristic
     (locked is introduced to help the Modelica translator determining
      the different structural configurations, if for each configuration
      special code shall be generated)
  */
  
  startForward = pre(mode) == Stuck and (sa > f0_max and s < (smax - L/2) or 
    pre(startForward) and sa > f0 and s < (smax - L/2)) or pre(mode) == 
    Backward and v_relfric > v_small or initial() and (v_relfric > 0);
  startBackward = pre(mode) == Stuck and (sa < -f0_max and s > (smin + L/2) or 
    pre(startBackward) and sa < -f0 and s > (smin + L/2)) or pre(mode) == 
    Forward and v_relfric < -v_small or initial() and (v_relfric < 0);
  
  locked = not free and not (pre(mode) == Forward or startForward or pre(mode)
     == Backward or startBackward);
  
  a_relfric = if locked then 0 else if free then sa else if startForward then 
    sa - f0 else if startBackward then sa + f0 else if pre(mode) == Forward
     then sa - f0 else sa + f0;
  
  /* Friction torque has to be defined in a subclass. Example for a clutch:
       f = if locked then sa else if free then 0 else cgeo*fn*
                (if startForward  then  Math.tempInterpol1( w_relfric, mue_pos, 2)
             else if startBackward then -Math.tempInterpol1(-w_relfric, mue_pos, 2)
             else if pre(mode) == Forward then Math.tempInterpol1(w_relfric, mue_pos, 2)
             else -Math.tempInterpol1(-w_relfric, mue_pos, 2));
  */
  
  // finite state machine to determine configuration
  
  mode = if free then Free else (if (pre(mode) == Forward or pre(mode) == Free
     or startForward) and v_relfric > 0 and s < (smax - L/2) then Forward else 
    if (pre(mode) == Backward or pre(mode) == Free or startBackward) and 
    v_relfric < 0 and s > (smin + L/2) then Backward else Stuck);
  
end FrictionBase;

Modelica.Mechanics.Translational.Interfaces.Compliant

Information

This is a 1D translational component with a compliant connection of two translational 1D flanges where inertial effects between the two flanges are not included. The absolute value of the force at the left and the right flange is the same. It is used to built up springs, dampers etc.

Release Notes:

• First Version from August 26, 1999 by P. Beater (based on Rotational.Compliant)

Modelica definition

partial model Compliant 
  "Compliant connection of two translational 1D flanges" 
  Flange_a flange_a 
    "(left) driving flange (flange axis directed INTO cut plane, e. g. from left to right)"
    ;
  Flange_b flange_b 
    "(right) driven flange (flange axis directed OUT OF cut plane)";
  SI.Distance s_rel "relative distance (= flange_b.s - flange_a.s)";
  flow SI.Force f 
    "forcee between flanges (positive in direction of flange axis R)";
equation 
  s_rel = flange_b.s - flange_a.s;
  flange_b.f = f;
  flange_a.f = -f;
end Compliant;

Modelica.Mechanics.Translational.Interfaces.TwoFlanges

Information

This is a 1D translational component with two flanges. It is used e.g. to built up parts of a drive train consisting of several base components.

Release Notes:

• First Version from August 26, 1999 by P. Beater (based on Rotational.TwoFlanges)

Modelica definition

partial model TwoFlanges 
  "Component with two translational 1D flanges " 
  Flange_a flange_a 
    "(left) driving flange (flange axis directed INTO cut plane, e. g. from left to right)"
    ;
  Flange_b flange_b 
    "(right) driven flange (flange axis directed OUT OF cut plane)";
end TwoFlanges;

Modelica.Mechanics.Translational.Interfaces.Flange_a

Information

The following variables are transported through this connector:

  s: Absolute position of the flange in [m]. A positive translation
     means that the flange is translated along the flange axis.
  f: Cut-force in direction of the flange axis in [N].

Modelica definition

connector Flange_a 
  "(left) 1D translational flange (flange axis directed INTO cut plane, e. g. from left to right)"
   
  
  
  SI.Position s "absolute position of flange";
  flow SI.Force f "cut force directed into flange";
end Flange_a;

Modelica.Mechanics.Translational.Interfaces.AbsoluteSensor

Information

This is the superclass of a 1D translational component with one flange and one output signal in order to measure an absolute kinematic quantity in the flange and to provide the measured signal as output signal for further processing with the Modelica.Blocks blocks.

Release Notes:

• Version 1.0 (July 18, 1999) by Martin Otter:
  Realized.

Copyright © 1999-2002, Modelica Association and DLR.

Modelica definition

partial model AbsoluteSensor 
  "Device to measure a single absolute flange variable" 
  
  extends Modelica.Icons.TranslationalSensor;
  
  Flange_a flange_a 
    "(left) flange to be measured (flange axis directed INTO cut plane, e. g. from left to right)"
    ;
  Modelica.Blocks.Interfaces.OutPort outPort(final n=1);
end AbsoluteSensor;

Modelica.Mechanics.Translational.Interfaces.RelativeSensor

Information

This is a superclass for 1D translational components with two rigidly connected flanges and one output signal in order to measure relative kinematic quantities between the two flanges or the cut-force in the flange and to provide the measured signal as output signal for further processing with the Modelica.Blocks blocks.

Release Notes:

• Version 1.0 (July 18, 1999) by Martin Otter:
  Realized.

Copyright © 1999-2002, Modelica Association and DLR.

Modelica definition

partial model RelativeSensor 
  "Device to measure a single relative variable between two flanges" 
  
  extends Modelica.Icons.TranslationalSensor;
  
  Flange_a flange_a 
    "(left) driving flange (flange axis directed INTO cut plane, e. g. from left to right)"
    ;
  Flange_b flange_b 
    "(right) driven flange (flange axis directed OUT OF cut plane)";
  Modelica.Blocks.Interfaces.OutPort outPort(final n=1);
end RelativeSensor;