% FuzzyEx1plot.m
%
% Example of fuzzy logic used to control a screw-down motor that controls
%  how far apart rolls in a steel mill will be.  The motor lacks feedback
%  control and coasts into place.  The objective of the fuzzy logic
%  system is to output the time that the motor should be turned off
%  so that it will end up at the correct final position.  Friction on
%  the mill varies with position.  (Data is stored in FuzzyStopDist.m function.)
%
% The plotting of the estimated stop distance surface is accomplished by
%  by processing (x1, x2) points through the entire fuzzy logic system.

% Create mesh for plot
x1_limits = [0, 2.4];     % [min, max] for x1 (size of move).
x2_limits = [0, 3.0];     % [min, max] for x2 (final position).
num_pts_x1_and_x2 = 101;  % number of pts in both x1 and x2 directions.

% Create the x1,x2 pts
x1_spacing = (x1_limits(2)-x1_limits(1))/(num_pts_x1_and_x2 - 1);
x2_spacing = (x2_limits(2)-x2_limits(1))/(num_pts_x1_and_x2 - 1);
x1 = x1_limits(1) : x1_spacing : x1_limits(2);
x2 = x2_limits(1) : x2_spacing : x2_limits(2);
[xx1,xx2] = meshgrid(x1,x2);

% Evaluate the fuzzy logic surface at points on the grid.
for size_of_move_index = 1:size(xx1,1)
  for final_pos_index = 1:size(xx2,2)
    size_of_move = xx1(size_of_move_index, final_pos_index);
    final_pos = xx2(size_of_move_index, final_pos_index);

    y(size_of_move_index, final_pos_index) = ...
      FuzzyStopDist(xx1(size_of_move_index, final_pos_index), ...
                    xx2(size_of_move_index, final_pos_index));
  end
end

% Plot the surface.
figure(1)
surf(xx1,xx2,y)
set(gcf,'color','white')
xlabel('size of move (inches)')
ylabel('final position (inches)')
zlabel('stop distance (inches)')
title('Fuzzy logic system for predicting stop distance')