We’ve been working on tuning our shooter using the pidf closed-loop controller on the talon srx, but we encountered an interesting issue when we switched which talon we were using. We had the shooter keeping at a very consistent rpm before switching talons, as well as recovering from shooting very quickly. When we moved from using a temporary test bed to a more permanent mounting location, which involved upgrading the talon used to a brand new talon.
After a few hours of testing and tuning, we were nowhere near to the level of accuracy we were able to achieve before we upgraded the talons in only about one hour.
There were two differences we were able to find between the two setups:
- Hardware revision changed from 1.4 to 1.7
- Firmware changed from 2.20 to 2.23
We don’t have any reason to believe that the hardware revision would affect this, but looking at the technical resources for the talon, I would not be surprised if the firmware was the cause of this change, as a listed change between the revisions is “Velocity closed-loop timing improvements,” though I think it’s strange that this change came partway through build season.
I’m sure our issue is mostly just not spending enough time tuning the controller, but if we can avoid it I would prefer to not have to spend that time.
Now I have a few questions:
- Has anyone else noticed similar changes in their testing?
- Is there any reason that not upgrading the firmware would harm the performance of our system?
- Would upgrading to the new firmware (as of 2-23-17), version 2.34, help in this regard?
- Does anybody know of effective tuning methods for velocity pid that could be implemented relatively quickly to retune the system?
Thank you!