Getting error message when running Runge Kutta solution...

The code that produces the errors is below:

clc;

mass = 13.5;

Jx = 0.8244;

Jy = 1.135;

Jz = 1.759;

Jxz = 0.1204;

G = Jx*Jz-Jxz^2;

G1 = Jxz*(Jx - Jy + Jz)/G;

G2 = (Jz*(Jz-Jy)+Jxz^2)/G;

G3 = Jz/G;

G4 = Jxz/G;

G5 = (Jz-Jx)/Jy;

G6 = Jxz/Jy;

G7 = ((Jx-Jy)*Jx +Jxz^2)/G;

G8 = (Jx/G);

p = 0;

q = 0;

r = 0;

l = 0.0000;

m = 0.0000;

n = 0.0000;

tspan = [0 10];

%[t,q] = ode45(@(t,q) (G5*p*r-G6*(p^2-r^2)+m/Jy), tspan,0);

%plot(t,q);

%pdot = (G1*p*q-G2*q*r + G3*l+G4*n);

[t,p]=ode45(@(t,p) (G1*p*q - G2*q*r + G3*l + G4*n),[0 10], 0.1);

plot(t,p,'--r');

disp(p);

disp(t);

[t,q] = ode45(@(t,r) (G5*p*r - G6*p*p - G6*r*r + m/Jy), [0 10],0);

plot(t,q,'--g');

[t,r] = ode45(@(t,r) (G7*p*q - G1*q*r + G4*l + G8*n), [0 10],0);

plot(t,r,'--b')

The output with the error messages follows:

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0

0.2500

0.5000

0.7500

1.0000

1.2500

1.5000

1.7500

2.0000

2.2500

2.5000

2.7500

3.0000

3.2500

3.5000

3.7500

4.0000

4.2500

4.5000

4.7500

5.0000

5.2500

5.5000

5.7500

6.0000

6.2500

6.5000

6.7500

7.0000

7.2500

7.5000

7.7500

8.0000

8.2500

8.5000

8.7500

9.0000

9.2500

9.5000

9.7500

10.0000

Error using *

Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of rows in the second matrix. To

perform elementwise multiplication, use '.*'.

Error in test>@(t,r)(G5*p*r-G6*p*p-G6*r*r+m/Jy) (line 30)

[t,q] = ode45(@(t,r) (G5*p*r - G6*p*p - G6*r*r + m/Jy), [0 10],0);

Error in odearguments (line 90)

f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in test (line 30)

[t,q] = ode45(@(t,r) (G5*p*r - G6*p*p - G6*r*r + m/Jy), [0 10],0);

Answer 1

[Star Strider]

I’m not certain what you’re modeling. First, using norm to return a scalar solves the first problem of the differential equaton returning a (41x1) vector, however in the expression after that, ‘p’ is (41x1) and ‘q’ is (49x1). You will have to figure out what you want to do with them, and where the error is.

clc;
mass = 13.5;
Jx = 0.8244;
Jy = 1.135;
Jz = 1.759;
Jxz = 0.1204;
G = Jx*Jz-Jxz^2;
G1 = Jxz*(Jx - Jy + Jz)/G;
G2 = (Jz*(Jz-Jy)+Jxz^2)/G;
G3 = Jz/G;
G4 = Jxz/G;
G5 = (Jz-Jx)/Jy;
G6 = Jxz/Jy;
G7 = ((Jx-Jy)*Jx +Jxz^2)/G;
G8 = (Jx/G);
p = 0;
q = 0;
r = 0;
l = 0.0000;
m = 0.0000;
n = 0.0000;
tspan = [0 10];
%[t,q] = ode45(@(t,q) (G5*p*r-G6*(p^2-r^2)+m/Jy), tspan,0);
%plot(t,q);
%pdot = (G1*p*q-G2*q*r + G3*l+G4*n);
[t,p]=ode45(@(t,p) (G1.*p.*q - G2.*q.*r + G3.*l + G4.*n),[0 10], 0.1);
plot(t,p,'--r');

disp(p);

    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000
    0.1000

disp(t);

         0
    0.2500
    0.5000
    0.7500
    1.0000
    1.2500
    1.5000
    1.7500
    2.0000
    2.2500
    2.5000
    2.7500
    3.0000
    3.2500
    3.5000
    3.7500
    4.0000
    4.2500
    4.5000
    4.7500
    5.0000
    5.2500
    5.5000
    5.7500
    6.0000
    6.2500
    6.5000
    6.7500
    7.0000
    7.2500
    7.5000
    7.7500
    8.0000
    8.2500
    8.5000
    8.7500
    9.0000
    9.2500
    9.5000
    9.7500
   10.0000

[t,q] = ode45(@(t,r) norm(G5.*p.*r - G6.*p.*p - G6.*r.*r + m./Jy), [0 10],0);
plot(t,q,'--g');

G7

G7 = -0.1683

p

p = 41x1

0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000

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q

q = 49x1

0 0.0001 0.0001 0.0001 0.0002 0.0004 0.0007 0.0009 0.0012 0.0022

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G7.*p.*q

Arrays have incompatible sizes for this operation.

G1.*q.*r
G4.*l
G8.*n
de(t,r)

[t,r] = ode45(@(t,r) (G7.*p.*q - G1.*q.*r + G4.*l + G8.*n), [0 10],0);
plot(t,r,'--b')

.