Demonstrate the automatic spin up for ComStar.

Since version 2.
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See also SpinREst, ComStar, Constant, Plot2D, TimeGUI, Accel
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Contents

%--------------------------------------------------------------------------
%   Copyright (c) 1994-1996 Princeton Satellite Systems, Inc.
%   All rights reserved.
%--------------------------------------------------------------------------

Global for the time GUI

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

rPM2RPS  = Constant('RPM to Rad/Sec');
rPS2RPM  = Constant('Rad/Sec to RPM');

CEPStD   = ComStar('SSA CEP StD');

Spin up from 5 to 10 rpm

%-------------------------
omega     =  5*rPM2RPS;
omegaF    = 10*rPM2RPS;

Use the nominal acceleration-should take 261 seconds

%-----------------------------------------------------
accelNom  = 0.002; % rad/sec^2

The Kalman Filter is interrupt driven from the sun sensor pulse

%----------------------------------------------------------------
nSim      = 50;

Size the arrays

%----------------
pwPlot    = zeros(1,nSim);
xPlot     = zeros(1,nSim);
tPlot     = zeros(1,nSim);
pwMaxPlot = zeros(1,nSim);
omegaPlot = zeros(1,nSim);

Initialize the Kalman Filter

%-----------------------------
x         = omega;
K         = 0.5;

Assume the accleration is known accurately

%-------------------------------------------
accel     = 0.9*accelNom;
time      = 0;

pulsewidth    = 0;
pulsewidthMax = 0;

Initialize the time display

%----------------------------
T                      = 2*pi/omega;
tToGoMem.lastJD        = 0;
tToGoMem.lastStepsDone = 0;
tToGoMem.kAve          = 0;
[ ratioRealTime, tToGoMem ] =  TimeGUI( nSim, 0, tToGoMem, 0, T, 'ComStar Spin Up' );

Simulate

for k = 1:nSim

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

  xPlot(k)       = x;
  tPlot(k)       = time;
  pwPlot(k)      = pulsewidth;
  omegaPlot(k)   = omega;

  % The pulsewidth is either the full spin period or whatever is needed
  % to reduce the spin rate to the final rate
  %--------------------------------------------------------------------
  pulsewidthMax  = 2*pi/omega;
  pulsewidth     = min(pulsewidthMax,(omegaF-omega)/accelNom);

  % The rate simulation
  %--------------------
  omega          = omega + accel*pulsewidth;

  % Measured time from the last pulse
  %----------------------------------
  T              = (2*pi + 0.5*accel*pulsewidth^2)/omega + CEPStD*randn;

  % Update the estimate
  %--------------------
  x              = SpinREst(accelNom, K, x, T, pulsewidth);

  time           = time + T;

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

end
TimeGUI( 'close' )

j = 1:k;

Plot2D(tPlot(j),[omegaPlot(j)*rPS2RPM;(omegaPlot(j)-xPlot(j))*rPS2RPM;pwPlot(j)],'Time (sec)',...
       {'Spin Rate (rpm)' 'Spin Rate Error (rpm)' 'Pulsewidth (sec)'}, 'Spin Up');


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

Published with MATLAB® R2019a