Post processing

[T_M_S]

Happy new 2022 year
I would like to ask if it is possible to overlay FFT plots of 2 (or more) curves (plots) within one plot. I would like to compare one result with the other and being able to see FFT overlayed over each other with the same haxis/vaxis scale would be extremely helpful.

Thank you,
Ted

 

[T_M_S]

Greg,
Can you recommend a good text or video tutorial on DOE?

Thank you,
Ted

 

[T_M_S]

Also, may be you can suggest a good (concise and to the point) video course on Matlab? There are too many of those on youtube so this is not easy to choose a good one.

Thank you,
Ted

 

[GregLocock]

DOEs in general, hmm, we did a couple of 3 day workshops on them as part of our systems engineering course. As such I just have course notes. not textbooks. I'll check my statistics textbook later on today. The basic idea is pretty straightforward, I wouldn't get too worked up about noise factors and inner and outer arrays, for CAE.

The on-line matlab on-ramp from mathworks is pretty good, and if you want to take it further then there are several MOOCs

https://www.edx.org/search?q=matlab

Incidentally if you don't want to buy Matlab then Octave is free and good, and Scilab is somewhat similar and also good.



Cheers

Greg Locock


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[T_M_S]

Many thanks Greg.
I already started with on-ramp - it is indeed pretty good!

Thank you,
Ted

 

[GregLocock]

The killer app for MATLAB is Simulink, at least in the ADAMS world, because you can build control systems in Simulink and then run them from Adams. So for example you could set your EPAS up in Simulink and then use it instead of the ADAMS epas subsystem, which is not sufficiently complicated. Same with semi active shocks.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[T_M_S]

Thanks Greg, I will surely do my best to learn Simulink as well as Simscape.

One random question - in Adams, at the start of simulation, is it possible to have the vehicle model seat on the rig pads in the state of equilibrium rather than having it drop on the pads from the sky as it does now?

Another question regarding using Matlab as postprocessor for Aride simulations (while I'm going through onramp courses) - is it possible to automate importing the data file,processing it etc? I guess that answer is yes and it simply requires writing/saving an appropriate script?

Thank you,
Ted

 

[GregLocock]

"is it possible to automate importing the data file,processing it" How did you get your data into excel? The first step is to get the output file into a readable format, everything I use is proprietary.

https://www.mathworks.com/matlabcentral/fileexchange

has a few to try.

yes once you have everything set up it is very easy read multiple files in and do exactly the same to them. I can't show you because its proprietary, but basically we have a toolbox that is called by adams when we hit post process, which turns our output files into the same format as we get from real car data, and is then analysed exactly as if it was a real car. Even better, we can drive adams with the speed and steering wheel angle time history we get from the real car, so we are driving the model the same, and analysing it the same (not sure if that is a standard feature, we've customised car quite a lot).


So far as the 4poster goes, no idea, probably not. But you could alter the acf to stop the sim after it has settled and then restart it. I don't know how to do that, but a resource worth looking at is the ADAMS knowledge database, which has a forum where you can ask questions and poke MSC.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[T_M_S]

Thanks Greg,
I will have to get a little more experienced with Matlab in order to do it (automate import and processing) but hopefully I will get there some day

"So far as the 4poster goes, no. But you could alter the acf to stop the sim after it has settled and then restart it. I don't know how to do that, but a resource worth looking at is the ADAMS knowledge database, which has a forum where you can ask questions and poke MSC."
Here's an idea - use arbitrary solver functions for displacement inputs and that function would have the rig pads still for a couple of seconds and than start that sine sweep. Another option is to set the simulation slightly longer and set an appropriate frequency sweep rate and use Matlab tbl.Properties.StartTime to start processing when that "landing" shock has ended.

Back to onramp tutorials.

Thank you,
Ted

 

[T_M_S]

Greg,
Doing my first baby steps analysing acar 4post data in Matlab. May I ask you a couple of questions in this regard?

I think that best I post it in specific here

https://www.eng-tips.com/threadminder.cfm?pid=575

Thank you,
Ted