Trouble using Bode(sys)

I try using the bode function and i get an error that says "Error using DynamicSystem/bode

Dimensions of arrays being concatenated are not consistent." I have seen bode being used even what the arrays are not the same size. Anybody know what's wrong? (I just ran it in this question box and it worked now so why wont it work for me on my MATLAB? I have the control systems toolbox.

m = 2;
b = 5;
k = 600;
Ybar = 20;
sys = tf([k],[m b k]);
figure
hold on
bode(sys)
grid on

Answer 1

[Star Strider]

You could have a path problem.

Run these:

restoredefaultpath

rehash toolboxcache

from a script or your Command Window to see if that solves the problem.

[Eli Wolkenstein]

Didn't work same error message and same empty plot.

[Eli Wolkenstein]

[Star Strider]

At this point I suggest that you Contact Support . Include a link to this thread so they know what steps you’ve already taken, and the results.

It might be necessary to uninstall and reinstall MATLAB.

Meanwhile, use MATLAB Online to complete the assignment. That’s a temporary work-around until you can get it working on your computer again (although I use it extensively for prototyping Answers code, since it doesn’t have the 55 second limit that the online Run feature has, and it’s actually easier to use for that purpoose). You’ll have access to everything you’re licensed for.

[Serigne MBENGUE]

hi. This solution works. Thanks

[Star Strider]

@Serigne MBENGUE --

My pleasure!

A Vote would be appreciated!

Answer 2

[Manoj Mirge]

It might be possible that you have your own custom “tf" or “bode" function defined somewhere in your MATLAB path and at the time of calling those functions in your MATLAB script the script is calling the custom function instead of MATLAB’s built in “bode” and “tf" functions.

To check if you have a local custom function shadowing the MATLAB’s built-in function you can use “which" function. If you have a local function shadowing the built-in function, you can delete that function or remove that function from MATLAB path.

You can read more about how to use “which” function in the below link:

https://www.mathworks.com/help/matlab/ref/which.html

[Eli Wolkenstein]

when I run the which function it returns this:

>> which tf

C:\Program Files\MATLAB\R2023a\toolbox\control\ctrlmodels\@tf\tf.m % tf constructor

>> which bode

C:\Program Files\MATLAB\R2023a\toolbox\control\ctrlobsolete\bode.m

which I believe are the correct functions for what I'm trying to use. It's not showing me any other "tf" or "bode" custom function I might hve made.