Motion Profile Generator

Technical Programming
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21

Hello!

so i was able to get pathplanner installed and generating data but i’m not have much success getting the PID terms tuned for my robot. I’ve got a small test robot that i’ve built using all the same FRC control system parts that we all use. The robot is about 18"x20" and I have a single 775 Pro motor driving each left and right side and I’ve got a 30:1 gear ratio on each side drive train. ha…perhaps i should post a pic of this thing to help you visualize). Anyway, it seems that the pathplanner data is basically working and driving the wheels to the correct distance (while the robot is on blocks), but its very jerky I’m assuming the PID terms are not correct. I only have P currently and i’ve tried to use a few different values for that, but no luck yet! so i ‘think’ its PID related, but maybe not?

22

If there is jerky movement it is most definitely due to PID. We had the same issue. We only used P and D and our issue was we had P too high and D too low.

23

The way that a robot behaves on blocks vs. on the carpet is very different. We once ran our path following code on blocks (code that worked very well on carpet) and the wheels oscillated wildly.

It is best to tune these types of algorithms on the carpet.