First major update of Build Season!
We’ve been designing out the robot, as you would expect. That started with a set of Master Sketches on day 1/2, which were of course iterated on as the days passed by. These are pictured below (The climbers are not included - they will sit on either side of the shooter column in the back).
These mainly allow us to start to work out systems integration, and more importantly, allow us to put together a general design, figuring out sensors, motors, and the geometry of the individual mechanisms, before breaking up into our respective subteams.
While working out all that, we also put together a schedule for the whole season, leading up to our first event in Week 2.
The important thing to note is driver practice; we set aside 2 weeks for them to have the robot effectively unrestricted. No matter what, they had to have it by then; even if we had to leave out the turret, climb, etc in the meantime. Besides that, the rest of the schedule is ambitious, having us have the robot mechanically done by mid week 3, however, we are confident it can be done.
This will be our first time really using a schedule like this - the idea is that we will talk about it and our progress at the start and end of every meeting, and try as a team to keep each other accountable to the schedule.
As for individual mechanisms, we prioritized the shooter, intake, and turret. Drivetrain design was already done from offseason and we were happy with where that was, and we determined shooter/turret to be important for drivers to have early, and the mechanisms requiring the most prototyping.
As for why we also prioritized turret, we had never attempted it before, and the entire robot was somewhat based around it. So, if we weren’t going to be able to realistically make it, we wanted to know right away so we could account for that. However, we did get something we are happy with, so we will move forward with it.
Here’s some pictures of our progress thus far on the intake and shooter
The intake is a 3 roller over-the-bumper intake, inspired by the many teams that did similar ones in 2020/2021. What is new, however, is the extra roller on the front; we are planning to experiment with some sort of “flapper roller” to catch bouncing cargo and direct it into the intake itself.
Here is the rough sketch and prototype of the shooter. 2021 bot for scale (and to power the motors). Because we have to shoot so flat, hence meaning very little shooter travel (under 20deg for a “fender shot”), we determined that we would need a “kicker tunnel” - something above the turret to accelerate the ball before it reached the shooter, allowing the shooter itself to mainly be used to aim the ball and also preserving it’s momentum, hopefully negating the need for an inertia wheel. This prototype exists primarily to test that theory, as well as to test hood and wheel material, and overall compression. We haven’t done enough prototyping yet, and I’ll post more as I learn more, but, with a grain of salt, what I have found so far is:
- The “kicker tunnel” seems to work. It increased repeatability and exit velocity, although I won’t say it’s necessary since almost all our testing thus far has been while using it.
- These balls compress quite a bit - up to and even over 2", even when fully pressurized
- Slick wheels seem to struggle to get traction on the ball and slip a lot - we had to increase compression quite a bit to do that, enough that we were throwing off shots from them “popping” to size as they left the shooter, even when using the exact urethane drum we used in 2020/2021.
- All our wheels were 4" - Colsons, AM HiGrips, and VEX VersaWheels all seemed to work well, while the aforementioned urethane drum was too slippery.
- Ball pressure seems to matter a lot, and we were noticing wildly different results, while ball “fuzz” (we intentionally used velcro and made one of the balls extra fuzzy) does not seem to have a notable impact.
The main things we will be testing going forward are going to be focused on getting repeatable shots even with different pressure on balls, and then once we do that, we will also use this for testing angles and flywheel RPM for shooting from different positions on the field. I will keep y’all posted on our findings as we continue to prototype this in the coming days.
Finally, the turret. This will be belt driven, powered by a NEO on a 1:5 MaxPlanetary into 18:180 belt reduction, giving it a “travel time” of the entire ~330deg in around half a second. We planned to do a N550, but considering the structure we will need to put on top of it - essentially the entire shooter prototype pictured above save for the wood frame holding it up - we decided it was safer to just “overpower” it and put a full size NEO on it. We will also use the integrated NEO encoder to keep position, with a hardstop to zero it off.
If you want to look into this more, all STEP files are in the google drive I linked in the first post. Anyways, I think that mostly summarizes our progress so far! Let me know if y’all have any questions! Good luck, and thanks for reading!
