MATLAB: When theta2 makes a complete cycle, I get error message.

MATLAB

clear all
clc
L2 = 10;
L3 = 20;
theta2 = 0:pi/18:2*pi;
% theta2 = pi/12;
omega2 = 1.6;
      theta3 = (2 * pi) + asin((-L2/L3)* sin(theta2))
   L1 = L2 * cos(theta2) + L3 * cos(theta3);
   C = [L2*sin(theta2)*omega2;-L2*cos(theta2)*omega2]
   D = [-L3*sin(theta3) -1 ;L3*cos(theta3) 0]  
    B = inv(D) * C
     plot(theta2,theta3)
   grid on
   xlabel('theta2(degrees)')
  ylabel('theta3(degrees)')
  title('crank angle(theta2) vs link 3 angle(theta3)')
   figure
   plot(theta2,L1)
   grid on
   xlabel('theta2(degrees)')
  ylabel('L1(m)')
  title('crank angle(theta2) vs link 1 angle(L1)')

Best Answer

clc; clear all ;
clear all
clc
L2 = 10;
L3 = 20;
theta2 = 0:pi/18:2*pi;
% theta2 = pi/12;
omega2 = 1.6;
theta3 = (2 * pi) + asin((-L2/L3)* sin(theta2)) ;
L1 = zeros(1,length(theta3)) ;
for i = 1:length(theta3)
    L1(i) = L2 * cos(theta2(i)) + L3 * cos(theta3(i));
    C = [L2*sin(theta2(i))*omega2;-L2*cos(theta2(i))*omega2] ;
    D = [-L3*sin(theta3(i)) -1 ;L3*cos(theta3(i)) 0] ;
    B = D\C ;
end
plot(theta2,theta3) ;
grid on
xlabel('theta2(degrees)')
ylabel('theta3(degrees)')
title('crank angle(theta2) vs link 3 angle(theta3)')
figure
plot(theta2,L1)
grid on
xlabel('theta2(degrees)')
ylabel('L1(m)')
title('crank angle(theta2) vs link 1 angle(L1)')
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