Generate plant model for given experimental input output data without using System Identification Toolbox

I am building a controller for a vacuum pump plant (input: RPM data, Feedback: Vacuum Pressure) however the manufacturer of the motor used in the pump is unable to share motor specs info

However I do have a test bed that can be run and I can record the input to and feedback from the plant

Is it possible for me to generate a plant model using this experimental data that can be replaced with a transfer function in Simulink?

I have seen tutorials using System Identification toolbox however unfortunately I donot and cannot obtain that tootlbox currently

Some of the other tutorials I have seen involve some complex math I am not very familiar with but I am willing to give it a shot if needed.

Kindly advice.

[Sam Chak]

Hi @Anirudh

First things first, you will need to collect the frequency response data from your oscilloscope. To do so, sweep the frequency logarithmically across the band. Then, using the oscilloscope, measure the steady-state amplitude and phase at each frequency. However, you may need to calibrate to compensate for the probe and channel delays, as well as to adjust the resolution and the Signal-to-Noise Ratio (SNR).

After that, upload the data by clicking the paperclip icon .

[Sam Chak]

Hi @Anirudh

If you do not have the System Identification Toolbox, you can still use some functions from the Control System Toolbox, Curve Fitting Toolbox, and Signal Processing Toolbox, which are included in the MATLAB Online (Basic). For example, the tfestimate(rpm, pressure) syntax may estimate a transfer function between the input signal rpm and the output signal pressure evaluated at a set of frequencies.

[Mathieu NOE]

hello

if I understand correctly, we are not here to look at raw time domain data ,we want to address how pressure is affected by a change of rpm, so see how pressure evolves as we make small steps changes in RPM ? I assume this is going to be a simple first order model including gain (may depend of rpm itself) , time constant and maybe some delay

so the test protocol could be to define a profile of rpm from low to max with step changes every x seconds (depends how fast the pump is responding)

[Mathieu NOE]

hello again @Anirudh

any data available ?