So we just wrapped up our first day of matches at our first competition.
At our workshop, we were shooting balls full field and hitting a very high percentage of shots. Now at competition we can barely shoot half that. It has become pretty clear that the balls get pretty beat up.
Our shooter wheels are hard wheels that aren’t very flexible. I think we have learned that we are going to change that, however that can’t happen this weekend.
Teams that have faced/ are facing this…how did you do it? We are thinking of adding a different hood we had… which has more compression. We also thought about trying to make our shooter wheel stickier.
Currious to hear if people have had any similar issues. I know another team told us they were having the exact same issue
The problem is because the balls get squishier as the competition goes on. As the balls compress easier, their is less normal force between the shooter wheels and the ball. That means there is less energy transfer and balls will shoot with less velocity and less distance.
I don’t think changing the wheels will help. Depending on how your shooter is setup it can easily be more likely to hurt than help. Increasing compression or re tuning pids for the softer balls (what I recommend) will help more. We re tuned our pids before our last match. Roughly 5% more surface speed solved our problem.
3996 was absolutely dominating early on with their full court shooter, but ended up with <25% accuracy by the end as well. Our shooter has like 1.5" of compression with 4" colsons and we were hitting with pretty good accuracy from mid to close range with any kind of ball ;
Expect the balls to be 10 time worse than what you’d like… 3" chunks missing were pretty common
We tuned our shooter with cut up and ripped balls to better simulate the competition balls, and like others have said, shooting up close makes the differences in balls less impacting on performance.
Join the club of rude awakenings.
We just spent everyday since coming back from our Week 1 event working on modifications.
As others have said in this thread, you should plan on shooting between Zones 1 and 2.
We ended up needing to coat our flywheel with duct tape to up our compression to cope with the balls. We also mutilated one of our test balls to mimic the condition of the comp balls for testing and we went from all our shots hitting low to most being pretty spot on.
Yup. Sorry I just assumed you were using a pid loop to control speed. Pid would help make sure you have the same speed every time, increasing repeatability (depending on what control you are using now // percent output?). As I said above, we increased surface speed by 5% and that solved our problem.
Our team struggled with that too. We have a hooded shooter using vision to aim. However, the best up balls come out slower, so we had two values we could adjust in the pits and mid game. We had a pitch error adjustment that would just up the reading from vision before any calculations in our dashboard. We also had a slider on a controller that added degrees directly to the hood angle. That way, we could make modifications to every aspect of our aiming. Worked well by the time we got it implemented.
We tried very hard to tune the shooter every few matches with what we were seeing on the field. We were constantly recording our shot pattern to make necessary adjustments. I also had many conversation with field staff, trying to keep the power cells equally damaged, instead of replacing a heavily broken cell by a brand new one, but it was not FIRST directive and they couldn’t comply with my requests, saying it would be better for playoffs.
After our last qualification, we used at least 30min on the practice field adjusting compression (we were about 4in compression at some point…), speed and angle to best accommodate the different power cells we had on hand (mostly damaged by our robot when practicing at home). We finally got pretty accurate shot and were confident for the quarterfinals.
For an (yet) unknown reason, we hit about 10% accuracy on our shots. Right after the match, we went back to the practice field to test with our 4 different balls and the setting were still good. It appears that the damaged cells of the playing field are damaged in a different way than what our robot can inflict to them, making tuning even harder.
At that point, we gave up the long shot and tried to tune a short shooter in the tight amount of time during playoff matches, and pulled a close final match. We were lucky enough to get a wildcard!
I still can’t understand precisely what we did or what happened between the quals and playoff. If I had good hope with the long shot strategy after the practice and first qualification day, my thoughts for that strategy might change for the championship. If we can’t use our own power cells to tune the shooter and can’t rely on the field to get a constant degradation (over a lot of disparities between the cells), this is no longer viable.
I hope FIRST will adjust their directives regarding PC replacement.
We’ve added a “more yeet” slider to our driver’s station so the drivers can up the rpm in real time if needs be, but right now we’re hoping to use the long shot in early games to rack up QPs, then transition to the short game as the need arises.
We used 4" Fairlane wheels and 2" of compression. From what we heard in the pits during our debriefs, they didn’t see a ton of variation in the ball shot consistency throughout matches. I don’t know if having softer wheels will change a lot.
I remember during the basketball game KingTec had an impressive shooter that measured the ball squish factor for each ball and used that to change shooter speeds. If it proves to be a big issue, this could be a way to go.
we ended up going with more compression with an old shooter hood we had, and it helped a lot. Still wasn’t perfect but much better. We didn’t anticipate the beat up balls being such an issue. I guess week 1 wasn’t a great gage either as I bet we were using a lot of balls that saw action in week 1. Our plan might be to literally drive our cars over the balls to prep them.
I did notice a lot of teams were using these big rubber like drum things as shooters… looks like they were 6 inches. Does anyone know what they were called? supposedly they expand at velocity as well? seem to be really popular in the first community.
At Arkansas, a common feature was to decrease compression as you go around the shooter wheel. Beginning with 2" compression, and leveling out to 1" compression at the exit point.
Anecdotally, we started our week 2 event with our shooter rpm at about 4300. Because we always shot from the exact same spot (initiation line, right in front of the trench), we would just kick up the rpm a bit if we noticed shots going low. By finals, we were running 4600 rpm.