Systematically pause Simulink model and continue from Matlab command line

Is it possible to have Matlab start a Simulink model (fixed step, discrete) and after each sample step, the model pauses, allows Matlab to do some data handling from the model, then waits for Matlab to tell the model to resume the next sample step? I have a very specific application that requires some functions in Matlab but I want to use Simulink to handle most of the heavy lifting.

Answer 1

[Kaustubha Govind]

What kind of data handling would you like to do in MATLAB? You might want to look at Access Block Data During Simulation, which lets you work your MATLAB code into the simulation process instead of artificially pausing/continuing.

[Thomas Marullo]

After each simulation step, I need to run the output data through various filters to check for validation of data. I can't just arbitrarily access the data during simulation. It has to be step wise. The matlab script may take a few seconds to complete before the simulink model can continue processing. I'm attempting to do it with triggered subsystems.

[Kaustubha Govind]

Thomas: The interface in the link I posted doesn't provide arbitrary access, but is indeed step-by-step - if you read the documentation, you will see that the mechanism involves attaching a PostOutputs callback to a specific block, so your function is called at every step that the block produces new outputs. It doesn't matter how long your code takes to execute - Simulink should wait until it's done.

[Thomas Marullo]

After looking through this example in more detail, I think this was the best option. Thanks!

Answer 2

[Guru]

Honestly, this is easier to do if you use MATLAB blocks within your Simulink to validate the results that you are looking for. However you can either use the Simulink Debugger commands from MATLAB to step through each individual block output based on sorted order, or you use:

set_param('model_name','SimulationCommand','pause') set_param('model_name','SimulationCommand','start') set_param('model_name','SimulationCommand','stop')

which are the command line functions that are equivalent to clicking the pause, play, stop buttons respectively.

Answer 3

[Guy Rouleau]

In most cases where I have seen users asking to control the execution of a model from MATLAB code, the most appropriate solution was to include the MATLAB code inside the simulation and let simulink control the execution.

Whatever data you wan to extract from the model at every step should be available on a signal line. So you it should be possible to feed it to a block that you can code with MATLAB code (MATLAB Function block, MATLAB s-function, interpreted MATLAB Function block, etc.) The block will do your processing and it will be available as a signal to other blocks for the next step.

[Thomas Marullo]

Typical that is what I do however in this case my MATLAB script is not compatible with the limitations of MATLAB embedded functions.

[Guy Rouleau]

What about the Interpreted MATLAB Function block, level 2 MATLAB S-Function, or the coder.extrinsic in the MATLAB Function block?

[Thomas Marullo]

The problem with using MATLAB inside of Simulink is that the code is not conducive to Simulink sampling. I am running a script, interpreting the results visually then deciding to continue or not. Simulink needs to wait for me to respond.

[Daniel Rutherford]

So, if I have a legacy matlab simulation (lets say a seeker), and Bubba wants me to use state dynamics from a 3-DOF Simulink Simulation to provide kinematic information periodically for each seeker update dwell, I should trash my legacy, 2000 hour test matlab simulation, and throw it into the disfunctionality of simulink? I'd rather rewrite the 3DOF in a matlab script.

There needs to be a better effort by matlab to integrate simulink results into a matlab script.

Preferably, I'd like to use a simulink model like I use the call to an ode function.

Answer 4

[Thomas Marullo]

Thanks for all your help. The method I used is by having a model run continuously and having triggered subsystems. Matlab command line triggers the system by using set_param to toggle a variable and then read back the data.