2012: Tuning the Jaguar's Speed Control PID Loop

[gpetilli]

Originally Posted by NotInControl

Hello all, I am the Control System Engineering for Team 2168 the Aluminum Falcons.

Its going to be very hard to lock down a method of tuning the PID gains without fully understanding the implementation of the Controller in the Jag.

No two PID implementations are equal, and depending on weather the PID controller is an Ideal, Series, or Parallel implementation greatly affects how to go about tuning them.

For example, in the ideal case changing P has an effect on both I and D, where as in a parallel implementation, each term can be independently tuned.

Does anyone know if this implementation has been made available? Last time I looked the documentation was no where to be found.

I am going to spend more time this season reverse engineering the Jags and understanding the implementation, as my team does use CAN and I would likes to move my control loops off the CRIO... I will post my results.

However in the mean time, I have been working on a complete video walk through to show a simple way to tune the gains of a PID controller using Matlab and Simulink.

All the videos are not up yet, but the most important one is, the video which shows how to tune the gains. The video, m-files and .mdl files, and complete labview project are also available from our team website at:

http://team2168.org/index.php/resour...ntrol-tutorial


The custom PID controller I use is also provided to be used by any team who so desires, all I ask is that you give credit to us, if you do use it. Even though the files are provided in labview, I will soon also provide a Java implementation.

The example in the video covers tuning position control gains but it is easy to extend the method for speed control on your own. In the next few days I will be posting an official walk through for tuning speed control gains as well.

Please check it out, and post any feedback you may have.


-Kevin

I applaud what you are trying to do - as an engineer, I strongly dislike the guess and check method. I downloaded your files, but am getting a "bad link" error in simulink for the PID Controller. I am using version 2008b will all toolboxes loaded. Also, your Matlab model appears to be setup for position, any intent to upgrade for speed mode?

I took a different path to a closed form solution. I am using Team 1640 - Sab-BOT-age Drivetrain Model to predict the step responce for various drive trains, using Astrom's (less overshoot than Ziegler-Nichols) equations to calculate P-I-D then as Either said - loading the calculated D into Jag P, calculated P into Jag I and 0 into Jag D. We are getting reasonable performance on the testbot. We intend to poll the Jaguars for step response data using voltage and PID control and compare results but things always take longer than you expect. This was all done with Excel spreadsheets - which i can share if you like.