why doesn't any data show up on my figure?

i'm trying to make a basic 4-bar linkage position tracking graph, but the graph shows up blank when i run it. any help?

%  Lengths of Linkages
a=269.755;
b=182.014;
c=345.91;
d=154.91;
e=110.524;
%  Initial Angles
theta0=0.544892;
theta20=2.504722;
theta30=0.612262;
alpha=0.559028959;
%  J-Values & Geometry Calculations
j1=d/a;
j2=d/c;
j3=(a^2 - b^2 + c^2 + d^2)/(2*a*c);
j4=d/b;
j5=(c^2 - d^2 - a^2 - b^2)/(2*a*b);
q=atan((a*sin(theta20))/(d-(a*cos(theta20))));
f=sqrt(a^2 +d^2 - 2*a*d*cos(theta20));
p=atan((sqrt(4*b^2*f^2 - (b^2 + f^2 - c^2)^2))/(b^2 +f^2 - c^2));
%  Coupler Position
xc=a*cos(theta20) + e*cos(p-q+alpha);
yc=a*sin(theta20) + e*sin(p-q+alpha);
z=-xc*cos(theta0) - yc*sin(theta0);
%  Range Of Input Angles
theta2=[(theta20-(degtorad(45))):pi/180:(theta20+(degtorad(45)))];
%  Loop
for i=theta2;
D=j5-j1+((1+j4)*cos(i));
E=-2*sin(i);
F=j5+j1-((1-j4)*cos(i));
theta3=2*atan((-E-sqrt(E^2 - 4*D*F))/(2*D));
camber=radtodeg(theta3-theta30);
q1=atan((a*sin(i))/(d-(a*cos(i))));
f1=sqrt(a^2 +d^2 - 2*a*d*cos(i));
p1=atan((sqrt(4*b^2*f1^2 - (b^2 + f1^2 - c^2)^2))/(b^2 +f1^2 - c^2));
xc1=a*cos(i) + e*cos(p-q+alpha);
yc1=a*sin(i) + e*sin(p-q+alpha);
z1=-xc1*cos(theta0) - yc1*sin(theta0);
height=z1-z;
end
%  Plot Results
figure
grid on
xlabel('camber angle(degrees)','FontSize',18)
ylabel('Wheel Travel(mm)','FontSize',18)
title('Camber Angle With Wheel Travel','FontSize',20)
plot(camber,height)

i'm pretty new to matlab so any help would be much appreciated. Cheers Michael

Answer 1

[Walter Roberson]

You overwrite camber and height each time through the "for i" loop.

camber = []; height = [];
for i = theta2
  ...
  camber(end+1) = radtodeg(....)
  [...]
  height(end+1) = z1-z;
end

[Michael]

thank you very much!