Contents

Demonstrate the bristle friction model with a velocity ramp.

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See also Plot2D, TimeGUI, RK4, FrictionBristle
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%-------------------------------------------------------------------------------
%   Copyright (c) 1999-2000 Princeton Satellite Systems, Inc.
%   All rights reserved.
%-------------------------------------------------------------------------------

Global for the TimeGUI

%------------------------
global simulationAction
simulationAction = ' ';

Simulation parameters

%----------------------
dT    = 0.0125;
nSim  = 2000;

d.friction(1).fStatic   = 0.005;
d.friction(1).fCoulomb  = 0.005/2;
d.friction(1).vStribeck = 0.1;
d.friction(1).sigma0    = 1;
d.friction(1).sigma1    = 1e-4;
d.friction(1).sigma2    = 4.0585e-05;
d.friction(1).maxC      = 1/dT;

Initialize the time display

%----------------------------
[ ratioRealTime, tToGoMem ] =  TimeGUI( nSim, 0, [], 0, dT, 'Bristle Friction Simulation' );

Initial conditions

%-------------------
xPlot = zeros(3,nSim);
t     = 0;
x     = 0;
v     = linspace(0,1,nSim);

for k = 1:nSim

  % Display the status message
  %---------------------------
  [ ratioRealTime, tToGoMem ] = TimeGUI( nSim, k, tToGoMem, ratioRealTime, dT );

  d.friction(1).v = v(k);

  x             = RK4( 'FrictionBristle', x, dT, 0, d.friction );
  tPlot(k)      = t;
  [zDot, f, c]  = FrictionBristle( x, 0, d.friction );
  xPlot(:,k)    = [x;f;c];

  % Update the time
  %----------------
  t  =  t + dT;

  % Time control
  %-------------
  switch simulationAction
    case 'pause'
      pause
      simulationAction = ' ';
    case 'stop'
      return;
    case 'plot'
      break;
  end

end
xPlot = [xPlot;d.friction(1).maxC*ones(1,nSim)];

yLbl = [  'Bristle ';...
          'Friction';...
          'CZDamp  '];
Plot2D( v, xPlot, 'Velocity (rad/sec)', yLbl, 'Bristle Friction','lin',['1  ';'2  ';'3:4'])


%--------------------------------------

Published with MATLAB® R2019a