output not changing

[Vaishali Patne]

I am trying to implement simple 2 state system of simple pendulum. though the x2 values are correct, the x1 is not changing at all. its a straight line with 0 values. what can be possible reasons.

I am using codeblock to run the c code and then plot the graph in matlab.

out[0] = x[2];
out[1] = (-98.1)*sin(x[1]) - 0.2*x[2] + u[0];

[Andreas Völz]

Hello Vaishali,

did you consider that array indices start with zero in C code? If the states x are position and velocity, then you probably want

out[0] = x[1];
out[1] = -98.1 * sin(x[0]) - 0.2 * x[1] + u[0]

Otherwise, what is x[0], x[1], x[2] and why is there no out[2]?

Regards,
Andreas

[Vaishali Patne]

There are only 2 states x(0) and x(1) . There is no x(2) - hence only out0 which is x0_dot and out1 which is x1_dot

[Andreas Völz]

Is the problem solved if you use the correct indices x[0] and x[1]? Otherwise, I need more information, e.g. the complete probfct.

[Vaishali Patne]

yes yes - solved -- thanks a lot for pointing out the basic error