# Can someone please help me out with this MATLAB code. It is giving error "INDEX EXCEEDS THE NUMBER OF ARRAYS_ INDEX MUST NOT EXCEED 1" ON LINE 69

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Ekundayo Alabi on 25 Apr 2022
Edited: DGM on 25 Apr 2022
clear ALL
m11 = int8 ( zeros (100) )
% T1t(i) = int8 ( Zeros (100))
% T2t(i) = int8( Zeros (100))
m1 = 1 ;
m2 = 2;
l1 = 1;
l2 = 1.2;
I1 = 0.12;
I2 = 0.25 ;
me = 2 ;
Ic1 = 0.25 ;
Ic2 = 0.6 ;
v1 = 5.5 ;
v2 = 2.7 ;
k1 = 2 ;
k2 = 1 ;
g = 9.8 ;
dt= 0.01
% t = 0 ;
Points = 30000
Data = zeros(Points,4);
D = [ 100 ; 50];
F = [ 30 ; 30 ]
theta1t(1) = 1 ;
theta2t(1) = 0.01 ;
thetav1t(1) = 0;
thetav2t(1) = 0 ;
thetaa1t((1)) = 0 ;
thetaa2t((1)) = 0 ;
for i = 1 : 1000
t(i) = i
t(i+1) = (i+1)* dt
qd1 = pi/6*(1-cos(2*pi*t(i))+1.5*sin(.5*pi*t(i)))
qd2 = pi/4*(1-cos(2*pi*t(i))+2.5*sin(.75*pi*t(i)))
qdv1 = (pi^2)/3*sin(2*pi*t(i))+(pi/6)*(1.5*0.5*pi)*cos(.5*pi*t(i))
qdv2 = (pi^2)/2*sin(2*pi*t(i))+(pi/4)*(2.5*0.75*pi)*cos(.75*pi*t(i))
qda1 = 2*(pi^3)/3*cos(2*pi*t(i))-(pi/6)*(1.5*0.5*pi)*(0.5*pi)*sin(.5*pi*t(i))
qda2 = (pi^3)*cos(2*pi*t(i))-(pi/4)*(2.5*0.75*pi)*(0.75*pi)*sin(.75*pi*t(i))
m11 = ((l2*l2*m2)/(2*l1*l2*m2*cos(theta2t(i))))+( l1*l1*(m1-m2))
m12 = ( l2*l2*m2) + ( l1*l2*m2*cos(theta2t(i)))
m21 = (( l2*l2*m2 )/(l1*l2*m2*cos(theta2t(i))))
m22 = ( l2*l2*m2 )
m = [ m11 , m12 ; m21 ,m22]
v11 = (-m2*l1*l2*sin(theta2t(i))*(thetav2t(i))*(thetav2t(i))) -( 2*m2*l1*l2*sin(theta2t(i))*(thetav1t(i))*(thetav2t(i)))
v21 = m2*l1*l2*sin(theta2t(i))*(thetav1t(i))*(thetav1t(i))
V = [v11;v21 ]
G11= (m2*l2*g*cos(theta1t(i)+theta2t(i))) + (( m1+m2)*l1*cos(theta1t(i)))
G21 = m2*l2*g*cos(theta1t(i) + theta2t(i))
G = [G11; G21]
T1(i) = m2*l2*l2*(thetaa1t(i)+thetaa2t(i)) + (m2*l1*l2*cos(theta2t(i))*(2*thetaa1t(i)) + thetaa2t(i)) + ((m1+m2)*l1*l1*thetaa1t(i)) - (m2*l1*l2*(sin(theta2t(i)))*thetav2t(i)*thetav2t(i)) - ( 2*m2*l1*l2*(sin(theta2t(i)))*thetav1t(i)*thetav2t(i))+(m2*l2*g*sin(theta1t(i)+theta2t(i))) + ((m1+m2)*l1*g*sin(theta1t(i)))+(v1*thetav1t(i))+(k1*sin(thetav1t(i)))
T2(i) = (m2*l1*l2*cos(theta2t(i))*thetaa1t(i)) +(m2*l1*l2*sin(theta2t(i))*thetav1t(i)*thetav1t(i)) + (m2*l2*g*sin(theta1t(i)+theta2t(i)))+(m2*l2*l2*(thetaa1t(i)+thetaa2t(i)))+(v2*thetav2t(i))+(k2*sin(thetav2t(i)))
T = [ T1(i) ;T2(i)]
n = inv(m)
thetaa = n*[T -V - G -F -D]
thetaa1t(i) = thetaa(1,1)
thetaa2t(i) = thetaa(2,1)
thetav1t(i+1) = thetav1t(i) +thetaa1t(i)*dt
thetav2t(i+1) = thetav2t(i)+ thetaa2t(i)*dt
theta1t(i+1) = theta1t(i) + thetav1t(i)*dt +( 1/2)*thetaa1t(i)*dt*dt
theta2t(i+1) = theta2t(i) + thetav2t(i)*dt + (1/2)*thetaa2t(i)*dt*dt
% Errors
e1t(i) = abs(theta1t(i)-qd1)
e2t(i) = abs(theta2t(i) - qd2)
ed1t(i) = abs(thetav1t(i)- qdv1)
ed2t(i) = abs(thetav2t(i)-qdv2)
end
ax = gca ;
ax.XAxislocation = "origin";
ax.YAxislocation ="origin";
xlabel ( 'time');
ylabel ('Torque1') ;
Legend ('T1','T2')
Plot ( t , T1,'r')
hold on
Plot (t,T2 ,'b')
hold off

DGM on 25 Apr 2022
Edited: DGM on 25 Apr 2022
thetaa1t and thetaa2t are initialized as scalars
thetaa1t((1)) = 0 ;
thetaa2t((1)) = 0 ;
I imagine you're trying to grow them, but when you make the assignments here, you're only assigning to the current index instead of i+1, so they never grow.
thetaa1t(i) = thetaa(1,1)
thetaa2t(i) = thetaa(2,1)
... that's probably why.

R2020a

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