Test the reaction wheel model with bristle friction.

A bristle friction model adds another state for the bristles.
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See also Plot2D, TimeGUI, RK4, RWABristle
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Contents

%--------------------------------------------------------------------------
%   Copyright (c) 1999 Princeton Satellite Systems, Inc.
%   All rights reserved.
%--------------------------------------------------------------------------

Global for the TimeGUI

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

Simulation parameters

%----------------------
dT    = 0.0125;
nSim  = 100;

Find the maximum static torque

%-------------------------------
RWABristle('clear');
RWABristle('initialize');
d    = RWABristle('get default datastructure');
tMax = RWABristle('get maximum static torque');

Input the friction model

%-------------------------
d.friction(1).fStatic   = 0.8*tMax;
d.friction(1).fCoulomb  = 0.4*tMax;
d.friction(1).vStribeck = 0.1;
d.friction(1).sigma0    = 1;
d.friction(1).sigma1    = 1e-4;
d.friction(1).sigma2    = 5e-4;
d.friction(1).maxC      = 0.1/dT;

d.friction(2) = d.friction(1);

Reinitialize

%-------------
RWABristle( 'clear' );
RWABristle( 'initialize', d );

Initialize the time display

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

Initial conditions

%-------------------
x     = [-0.5; -1;0;0];
xPlot = zeros(14,nSim);
tPlot = zeros( 1,nSim);
t     = 0;

Commanded voltage

%------------------
RWABristle( 'put voltage', [10;10] );

for k = 1:nSim

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

  x          = RK4('FRWABristle',x,dT,t);
  tPlot(k)   = t;

  xPlot(:,k) = [x;...
                RWABristle( 'get friction'      );...
                RWABristle( 'get torque'        );...
                RWABristle( 'get power'         );...
                RWABristle( 'get current'       );...
                RWABristle( 'get motor voltage' )];

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

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

end

yLbl = {'Omega' 'Bristle '  'Omega' 'Bristle ' 'Friction' 'Friction' ...
		'Torque'  'Torque' 'Power'  'Power'  'Current' ...
		'Current'  'Voltage'  'Voltage '};
Plot2D( tPlot, xPlot(1: 8,:), 'Time (sec)', {yLbl{1: 8}}, 'RWA Bristle Simulation')
Plot2D( tPlot, xPlot(9:14,:), 'Time (sec)', {yLbl{9:14}}, 'RWA Bristle Simulation')

Plot2D( tPlot, xPlot(9,:), 'Time (sec)', 'Power (W)', 'RWA Power')


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Published with MATLAB® R2019a