Derivative of state '1' in block 'PP_poly/Integrator1' at time 0.0 is not finite.

Hi, I am working on a simulink simulation of an autonomous three wheeled vehicle. My system right now is,

And I am getting not finite error from the integrator block that comes after inverse kinematics block. I know the reasons why simulink gives this error but I can not see why I am getting it. I tried to saturated integrator and memory block to prevent this but it didnt work. The inputs I am giving to integator are,

The signals are important for me, so I can not change their behaviour or anything.

[Sam Chak]

Can you label the Block names? It makes us easy to track which block that you are talking about.

Which one is the " Derivative of state '1'"?

What are these 3 signals? From which " Scope number" these signals are displayed?

From the plotted signals, is it true that the simulation can run up to 10 sec without showing any warning or error message? Only State #1 derivative is not finite at 0 sec, but becomes finite after that?

[Dogukan]

@Sam Chak Sorry let me make it easier to understand with only one scope. This is my system without integrator, it basically plans a path, calculates poses for my vehicle than I convert that poses into angular speeds for my wheels(w1, w2, w3).

And this is the scope I gave before but now with labels, these are inputs for integrator block.

Now, same system but with integrator,

Error is:

• Derivative of state '1' in block 'PP_poly/Integrator3' at time 0.0 is not finite.

I tried every integrator one by one all of them give the same error. It says integrator3 but I guess it is related with process order.

I am not sure what it means with derivative of state '1'.

No it does not run up to seconds without giving warning. That scope was without integrator block so that I can show you what are my inputs are.

[Dogukan]

@Sam Chak Sure, here you can see they are all nan. I am kinda confused why it is nan at the start.

[Dogukan]

@Sam Chak Okay I fixed it with MATLAB Function block where I put a if statement that if time is equal to zero then make these two signal zero and it fixed the problem thank you for your helps.

Answer 1

[Sam Chak]

Hi @Dogukan

It's good to hear that your problem is solved now. I moved my comment to the Answer section because it helped you to figure out what went wrong. If you find the tips helpful, please consider accepting ✔ and voting 👍 on the answer. Thanks!

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Can you right-click to show the value labels on the selected signals? It helps to investigate the issue. Something like shown below: