Syntax Error Simulink fcn block

The expression: (-3*B*L*L*u(4))/J+(a*L*u(1))+(a*L*u(2))+(a*L*u(3)) in 'omnirobotcontrol/Subsystem/theta_2dot' has a syntax error.

WhY I am getting this error. I can't see the wrong :(

[madhan ravi]

A picture of the model would help.

[lokman alici]

[lokman alici]

[lokman alici]

Thank you for your interest. I load the subsystem and all of my model.

[Walter Roberson]

you appear to be using a Math Block for the expression, not a MATLAB Function Block. Math blocks are much more restricted in what they permit.

[lokman alici]

Hi;

when I am using the Mtlab Function. I get a error like that:

Simulink cannot determine sizes and/or types of the outputs for block 'omnirobotcontrol/Subsystem/MATLAB Function2' due to errors in the block body, or limitations of the underlying analysis. The errors might be inaccurate. Fix the indicated errors, or explicitly specify sizes and/or types for all block outputs.

[Ameer Hamza]

Can you show the code inside the MATLAB function block?

[lokman alici]

function x_2dot = fcn(u)

J = 0.01;
B = 0.1;
K = 0.01;
R = 1;
L = 0.5;
a=1;
m=1;

x_2dot=(-3*B*u(4))/(2*m)-((a*sin(u(5))*u(1))/m)-((a*sin((pi/3)-u(5))*u(2))/m)+((a*sin((pi/3)+u(5))*u(3))/m);

end

Answer 1

[Ameer Hamza]

Try this

function x_2dot = fcn(u)
x_2dot = 0; % initialize to tell simulink about its size
J = 0.01;
B = 0.1;
K = 0.01;
R = 1;
L = 0.5;
a=1;
m=1;
x_2dot=(-3*B*u(4))/(2*m)-((a*sin(u(5))*u(1))/m)-((a*sin((pi/3)-u(5))*u(2))/m)+((a*sin((pi/3)+u(5))*u(3))/m);
end

[lokman alici]

thanks