Integrator does not accept input

Hello, I'm trying make a model in simulink of an inverted pendulum and I can't simulate the space state. It's still telling me about that the integrator does not accept the input. Does anyone know what do to in this situation?

The formula that I'm trying to simulate:

Simulation:

The error:

Matlab code:

%%Parameters
Mp = 0.272;                      
dM = 0.071;                     
g = 9.81;                      
J = 0.002;                      
Jw = 3.941*10^-5;                
b_theta = 0.82*10^-3;           
b_altha_kmke_Ra = 1.202*10^-4;  
km_Ra = 1.837*10^-4;

%%Matrice
A = [0 1 0 0;
    (Mp*dM*g)/J -(b_theta)/J 0 1/J*b_altha_kmke_Ra;
    0 0 0 1;
    -(Mp*g*dM)/J b_theta/J 0 -(J+Jw)/(J*Jw)*b_altha_kmke_Ra];
B = [0 0;
    -1/J*km_Ra 1/J;
    0 0;
    (J+Jw)/(J*Jw)*km_Ra -1/J]
C = [1 0 0 0;
    0 1 0 0;
    0 0 1 0;
    0 0 0 0];
D = [0 0; 0 0;0 0;0 0];

%%Build system 
sys = ss(A,B,C,D);
x0 = [5*pi/180;0;0;0]; %initial condition for the integrator

Answer 1

[Sam Chak]

Hi @Andrei Rotaru

The error is caused the mismatched matrix dimension. Do the following as shown in the graphics below should fix the issue. However, the built-in State-Space block can also perform the job equally.

[Andrei Rotaru]

Hi! Thanks a lot! It was very helpfull!

I need to do it manualy because I need the term x. And I don't know if i can extract it from the state space block individually.

[Sam Chak]

Hi @Andrei Rotaru

If you wish to extract the state variables x, then only the state matrix equations is necessary. First, the output and direct matrices must be constructed as shown below. Then, the individual state variables can be extracted using the "Demux" block.

A   = [zeros(3, 1), eye(3); zeros(1, 4)]

A = 4x4

0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0

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B   = [0; 0; 0; 1]

B = 4x1

0 0 0 1

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C   = eye(size(A))

C = 4x4

1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1

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D   = 0*eye(size(A))*B

D = 4x1

0 0 0 0

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