the given transfer function is an improper transfer function

i want to implement this transfer function in simulink: 0.05252s (it has only numerator) and i get this error: "the given transfer function is an improper transfer function. The order of the transfer function numerator mus be less than or equal to the order of the denominator" how can i implement this transfer function in simulink? (in matlab is possible, it is a pd regulator)

Answer 1

[jose luis guillan suarez]

finally i solved it adding a pole very far from the zero, like this:

0.05252s/(1+0.005252s)

whose output is exactly the same as the original system

[Vishal Chandrahaas V]

Nice Idea...

But, it's saying the following, and not working out for me.

Simulink cannot solve the algebraic loop containing 'Motor_trial/Gain' at time 5.0000000000000018 using the TrustRegion-based algorithm due to one of the following reasons: the model is ill-defined i.e., the system equations do not have a solution; or the nonlinear equation solver failed to converge due to numerical issues.

Answer 2

[Elio Sánchez G.]

You can use a gain block and a derivative block

[Vishal Chandrahaas V]

Do you mean this block??

Because there's an integrator block which has "1/s" on it, so I was expecting derivative block to has "s" or something like that....

Answer 3

[Walter Roberson]

Instead of implementing it as a transfer function, implement it as a gain block.

[jose luis guillan suarez]

if i implement it as a gain block it send me this error: "expresion 0.05252s for parameter gain cannot be evaluated" and is logical because it has an "s" so it's not a gain value.

[Walter Roberson]

Sorry, I was wrong about using a gain block for that purpose.

The documentation implies that you should be able to go to the MATLAB level and use tf2ss() to enter your transfer function and get out a state space that you then enter into a state space block. However, when I do that, I always seem to get out a flat zero output, and I do not know yet how to fix that.

[jose luis guillan suarez]

the tf2ss function sends me the same error as simulink:

Error using tf2ss (line 57) Order of denominator must be greater than or equal to order of numerator.

[Walter Roberson]

I think I used tf() and then genss() to get the matrices.

Answer 4

[Nahid]

how can i Solved?

[Walter Roberson]

What is there to be solved? You have to create a model using transfer function blocks. It does not look to me as if you are expected to be able to "tune" the model or adjust the parameters at run-time. You would create a variable or parameter named that should contain the last two digits of your student ID, and use that in the model, but it is not something you need to adjust. This is just a straight forward case of creating the model.

You do need to figure out what each kind of block is. The ovals with the +- around them are summation blocks. I am not positive what the K block is, possibly a gain . Most of the other blocks are transfer function blocks.