Hi everyone,

I am a fresh graduate working in industry (BEng Electronics Background).

I am trying to understand the control system modelling design process a bit better.

I am planning to use a LabVIEW programmed PID controller, but first want to model the system so that I have my PI values and can confirm I will get the correct behavior from the system.

What pieces of information do I need to gather in order to put together a document modelling the control system? I presume I will need some sort of block diagram showing the system, for example a motor output and some laser sensors for measuring movement going back into the closed loop control system.

If the motion created a linear motion (e.g. a lift going up and down) rather than a rotational one, and a sensor was able to tell the distance that the "lift" had moved, how would I go about modelling that system and selecting the right PID values for the control system?

Any insight into the design and modelling process will be greatly appreciated. I have some university level experience such as a quadcopter and IMU sensor but most of us struggled to get it working as it was an embedded systems module so not much focus on the actual control system modelling part. We had a control module but it was very basic. So am trying to get my skills up to scratch in industry. I have a copy of MATLAB if required. Any tutorials, examples, brief run through of the modelling process used in industry or other advice etc will be greatly appreciated.

Many thanks.

 

<p>If you have the Simscape toolbox for Matlab, you might start looking at the components there.</p>
<p>System modeling has two approaches: first-principles modeling (equations), or system identification (using measured input-output data to generate a model).</p>
<p>The first thing is to determine what purpose your model serves because that will define the acceptable level of accuracy, and the amount of detail required for the model. This will simplify the equations that you've derived. As an example, if you wanted to model gas flow, you might assume a constant compressibility factor of 0.97 instead of dynamically calculating one.</p>
<p>Ok, so let's say you've now got a model. How do you tune a PID controller? Matlab has various LTI tools, but the classic approach is to perform "bump tests" and apply some famous equations to get you in the ballpark of a tuning objective.</p>
<p>Since you have LabVIEW, I would lean towards using this instead of Matlab because LabVIEW can be set to run continuously, and has an HMI you can build to interact with the model.</p>