Control Loops

What they are, when to use them, and how to write them

With your friendly neighborhood Ryan Dunn

What are control loops?

• Used for controlling the change in a variable to allow higher accuracy in reaching a target value.

• Can be used for changing movement speeds, angles, rotation, or anything that you may need to make gradual.

• Also called PID loops due to the three different parts of a control loop. (We’ll get to that later)

When should control loops be used?

• Pretty much exclusively used on speed controllers such as Victors or, more recently, Talons.

• Movement speed is often run using PID loops• The more feedback, the better. Encoders can

be and normally are used for this increased feedback. Due to this need, control loops are also referred to as “feedback loops”.

What do PID loops look like?

• At this point, I will open up NetBen-ass and show you what a PID loop looks like because I’m sure I’ll have forgotten this part is in the presentation and won’t have it open in advance.

• #SuchForethought • Wow Such Beans

What makes a PID loop?

• P: Proportion• I: Integral• D: Derivative

• These three types of control make up PID loops. Time to explain.

A nice resource!

• Here’s a website that explains it in very basic terms: http://www.pc-control.co.uk/feedback_control.htm

• If you guys didn’t bring enough laptops, I will read it aloud with you guys, otherwise, type in the URL and read at your own pace.

Now you should understand these loops!

• Congrats! You did it!• Time for questions, concerns, more examples,

or just plain relaxation and socialization until time is up for the meeting.

• Enjoy and thanks for listening to my probably boring class, kiddos.