Domain error. To compute complex results, make at least one input complex.

Hi.An error occurred while running the simulation and the simulation was terminated

Caused by:

Domain error. To compute complex results, make at least one input complex, e.g. 'power(complex(a),b)'.

How can I fix it?

I have attached the Simulink file.

Thank you so much!

Answer 1

[Walter Roberson]

Your code is probably trying to take a negative number to a fraction power, which would give you a complex result. If that is what you want to do, then Simulink requires that you give it permission to use complex numbers by converting the input to complex using a call to complex(). And remember to take into account that this may cause output signals to become complex.

If you are not expecting a complex result there, then you need to debug how the input became negative there.

[Joel Van Sickel]

I can confirm Walter's answer that you are taking a negative number to a fraction of a power. For a model this complex, you should build up the individual pieces and get them working seperately before trying to combine everything.

[Mohammad Ali Sharifian]

This answer worked. I used abs() command to make it positive.

This problem happens in terminal sliding mode control when you have fractional powers.