replace initial matrix with a new one on Simulink

hi, I have this problem: I am making a simulink program for attitude determination, in the first step I use an initial matrix to calculate the rotation of my vector, after this I use the vector to calculate a new matrix, now I would like to repeat the same procedure but use the new matrix found to replace the initial one and so on for the following steps. how can I do?

[And Cav]

What I have is that: I start with a vector v and a matrix A0 and I compute s=A0*v, then I use s to find another matrix A1. Now I wanto ti find the new vector s using A1 instead of A0: s=A1*v. Then find A2 and use it: s=A2*v and so on. How can I do with Simulink?

Answer 1

[Fangjun Jiang]

All you need is a "Product" block and a "Unit Delay" block. Use the "Unit Delay" block to get the value of s from previous step.

[And Cav]

I’ll try. Thank you very much.

[And Cav]

Howevar, the value of s has to change at any step, what I wnat to do is to create a loop in which I substitute the value of A I’ve computed at the previous step to evaluate the new value of s. There’s no integration. I don’t know how to change the A at any step: s1=A1*v, then s=A2*v, s3=A3*v,… I use a product block but I don’t know how to change the input A at any step.

[Fangjun Jiang]

Use the "From Workspace" block to import the pre-defined A value at any time. Read the Help document of the block. There is a particular format that you meed to construct.

[And Cav]

Thank you. I knew this block, however I don’t know how to use it for my problem

[Fangjun Jiang]

Look at this link or your local help document. There is an example for reading in 2-D matrix signal.

https://www.mathworks.com/help/simulink/slref/fromworkspace.html

[And Cav]

Thank you. I’ll look at it.

[And Cav]

I’m trying to use the goto block, I’ve created a Matlab function (with the matlab function block) which sets A=A0 for t=0 and uses the goto matrix for t>0. However it doesn’t work. Do you know why?