Motor/encoder calculations - Accell, Decell and Stopping Distance

Other Hardware Motors, Mechanics, Power and CNC
1

Hi

I have a motor with an quadrature encoder attached.
Reading the encoder, I can get the counts okay.

I would like to be able to go to a certain position (count), using a set max speed, a set acell and decell rate, possible a S curve for smooth operation, including some sort sort of correction in case of over/under shoot.
I have searched this site but not found anything.
Google hasn't produced much either. Either some very theoretical paper or nothing complete

Any suggestion appreciated

K

2

You could use the AccelStepper library, keep track of the encoder counts while in your stepper.run() loop, then correct / stop / restart if what you expected to see isn't what the encoder says it sees.

Good luck!

3

Well, from what I can gather, I properly need to update speed/count/corrections every 1mS or so.
It seems that generally a PI function is used, instead of a PID, when it comes to motor control.

I'll spend some time trolling through PIC, Freescale, etc website looking for papers.
Some of the specific motor control chips may have some S/W that I can look at.

Thanks for the AccelStepper suggestion. Their site has some good stuff and the forum is usefull :slight_smile:
in case someone else is looking, here is the link
http://www.open.com.au/mikem/arduino/AccelStepper/

K