how to use previous value in simulink? [(k-1) value]

Question

Hyun Wook Kang 2023-6-4

回答： Les Beckham 2023-6-5

Currently, I am designing filtered velocity of the two wheel balancing robot, using encoder, and accelerometer, using following 2 equation.

I am trying to use MATLAB function block in simulink, which is the following picture.

But there is an error which says that I can't use direct feedback..

Can somebody help me with this problem?

Govind KM 2023-6-5

Could you share the exact error message?

Answer 1

Les Beckham 2023-6-5

It looks like what you need to do is remove the new_filtered_V input from your MATLAB function block and add this line at the top of your code:

persistent new_filtered_V;

That will eliminate the direct feedback and then the code will use the remembered previous value of new_filtered_V to update the new value.