Simulate a RWA with a PI rate controller.

------------------------------------------------------------------------
See also PIDesign, Plot2D, TimeGUI, RK4, RWA
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Contents

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

Clean up the workspace

%----------------------
clear RWA

Global for the TimeGUI

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

The control sampling period and the simulation integration time step

%---------------------------------------------------------------------
tSamp = 1;

Number of sim steps

%--------------------
nSim = 30;

Design the control loops

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

Tach loop

%----------
[aTL,bTL,cTL,dTL] = PIDesign( 0.7621,  0.5, 0.00954929658551, tSamp );

Plotting arrays

%---------------
xPlot = zeros( 5,nSim);
tPlot = zeros( 1,nSim);

Time statistics function

------------------------

[ ratioRealTime, tToGoMem ] =  TimeGUI( nSim, 0, [], 0, tSamp, 'RWASim' );

Initialize the wheel model

%---------------------------
RWA('initialize');

Measure the voltage and measurement gains

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

             RWA( 'put voltage',                 1, 1 );
             RWA( 'put speed',                   0, 1 );
torqueGain = RWA( 'compute torque',             [], 1 );
             RWA( 'put speed',                   1, 1 );
tachGain   = RWA( 'get tachometer measurement', [], 1 );

Rate command

%-------------
wCommand = 1;

Initialize the simulation

%--------------------------
t   = 0;
x   = 0;
xTL = 0;

Run the simulation

%-------------------
for k = 1:nSim

  % Motor values
  %-------------
  current      = RWA( 'get current',       [], 1 );
  power        = RWA( 'get power',         [], 1 );
  voltageMotor = RWA( 'get motor voltage', [], 1 );

  % Plotting
  %---------
  xPlot(:,k) = [x;current;power;voltageMotor;xTL];
  tPlot(k)   = t;

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

  % The RWA Tach Loop
  %------------------
  wError =  RWA('get tachometer measurement')/tachGain - wCommand;
  tW     = -dTL*wError - cTL*xTL;
  xTL    =  aTL*xTL + bTL*wError;
  RWA('put voltage', tW/torqueGain, 1 );

  % Update the equations of motion
  %-------------------------------
  x        = RK4( 'FRWA', x, tSamp, t );
  t        = t  + tSamp;

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

end

Plotting

%---------
yL = ['Rate         ';...
      'Current      ';...
	  'Power        ';...
	  'Motor voltage';...
	  'Command      '];

Plot2D( tPlot, xPlot, 'Time (sec)', yL, 'RWA')


%--------------------------------------
% PSS internal file version information
%--------------------------------------

Published with MATLAB® R2020a