Hey all, sorry for the delay in this post, we wanted to wait a couple more days to finish our CAD so we could have a lot of information to share with you! The following is primarily written by our Design team lead:
Prototyping
Unfortunately our team was one of many that was affected by the snow storms over the past month, cutting off quite a few needed meetings and delaying delivery times, but we did get some prototyping in.
Our horizontal shooter design worked ok, but after seeing 111âs very successful top-bottom shooter testing, we decided to try it ourselves. It certainly wasnât an optimal design, but even just a few shots was enough to show us that the note was much more accurate and traveled a lot further than our previous design
(Videos are attached in the post above)
We also built a setup to test the geometry for the intake we had using polycarbonate rollers. This prototype did not end up working as the compression between the ground and the front roller was too large and the note was consistently jamming. We angled it a little higher to adjust the compression, making it work, and once it got between the rollers and off the ground, it was good.
At this point we were three weeks into build season and had missed two weeks worth of in person meetings, had not been able to order/deliver any new parts for prototyping, was still struggling to find the time to continue prototyping different designs, and the furthest we had gotten in CAD was our KrayonCAD. Because of this, we decided to jump past a lot of our planned prototyping and begin the actual robot CAD. Part of our decision to do this was the fact that there was already so much detailed, extensive, and well thought out prototyping data for such a large amount of things from so many different teams, so we decided to utilize this data to help us make decisions.
Our robot this year is set on a six wheel WCD and features an over the bumper intake that works as a hand off to our shooter. The shooter is a top-bottom flywheel shooter that can pivot to allow us to be able to score speaker from a range of places on the field. Lastly, we plan to have a two stage TTB climb for the endgame chain.
Our intake uses four rollers to intake the note and direct it over the bumpers. We also decided to use a note catch similar to how the Cranberry Alarm catch is designed with a thin polycarb sheet and shaft standoffs keeping the note from making its way out of the intake. The polycarbonate side panels are shaped in a way to use our bumpers as a backup hard stop, and the slightly strange shape on the top is to avoid collision with our drive gearboxes when it swings back to handoff to the shooter.
Our intake is mounted through a MAXSpline dead axle. We are using one Vortex geared to drive two RT25 MAXSpline pulleys on the pivot. The reason for using pulleys over something else like #25 chain is simply because of maintenance. We donât necessarily need to worry about constant chain tensioning and making sure it is okay and we donât have to remove any links, if a belt were to break, replacements are cheap, and due to the pitch and width of the belts, two belts should be plenty strong to support this pivot. We attached the gearbox for all of this to the actual drive base directly so that we could save space on the belly pan for electrical and try to de-clutter the front of the robot as much as we could.
As we talked about before, we decided to go with the top-bottom style shooter with indexing rollers to feed into the flywheels. The indexer consists of four sets of 2â stealth wheels belted with GT2 to two NEO 550âs, one powering each side.
For the flywheels themselves, we are using 4â orange stealth wheels from Andymark. Again, we didnât have the time to test a whole lot of different wheels, but we have seen that these worked very well for other teams and the large radius and relatively light weight looked promising. Using two NEOâs, we plan to power the shooter at an upduction. We also chose to have the two (top and bottom) axles be mechanically geared together so that we can ensure they are always operating at the same speeds as we have had issues with inconsistencies between wheel speeds in shooters before and believe a difference in top/bottom speeds will not make much of a difference for this game.
We are also aiming to put our shooter on a pivot, utilizing vision to help us be able to score in the speaker from a range of places on the field. We decided that a MAXSpline live axle would work for this pivot, and, like the intake, we have one Vortex using RT25 pulleys.
This mechanism doesnât really have anything too special about it. We are going to use two 2-stage TTB telescoping kits to climb because we already had two base stage kits from an old robot. Weâll use one NEO on each and have hooks on each side (front/back) so that we are able to climb from either direction and not have to worry about turning around and aligning correctly. The only reason we think this would be important is because we donât have swerve, so turning to a singular correct position to climb would take more time than usual.
Weâll put out more details concerning calculations, some specific things weâll be using, and what we have planned to add in a few days once we start to assemble the robot and polish CAD
We recently finished our drivetrain (mostly, still waiting on sheet metal belly pan to attach). Controls has been working to program it and troubleshoot small issues, It is now driveable and very fun to drive. Here is what our controls lead has to share about the past week:
This week controls finalized shuffleboard design and worked on starting to publish things to the shuffleboard. We also finished up the auto code. The auto still needs to be tested and so does the shuffleboard. Those were the two main focuses this past week. controls also received the drivetrain and began testing on it. The drivetrain had some initial issues with a broken motor, possibly broken motor controller, and a broken radio which we had to fix before we could begin testing. Based on initial tests, it looks like our Gyro and encoders are all accurate and performing as expected. Our next step will be to test the auto. Our auto this year is different from the past. It is going to intake a value list of waypoints, and then drive between the waypoints. Some of the members of the comma separated list are going to be shoot or intake commands. The benefit of this auto is that it will be extremely dynamic and we can change what our auto route is in mere seconds or minutes before a match. Adding this flexibility is going to hopefully increase our competitiveness as a team, and also change how we can interact with our other alliance members.
Mechanical
Our mechanical team is wrapping up our final field element, the stage, and we just picked up our first batch of sheet metal parts from US Engineering. This year, we decided to paint some of our sheet metal to give our robot an extra pop. After talking to other teams, we settled on two layers of spray paint and one layer of a clear coat. The test pieces turned out really well and our new sheet metal parts are currently drying. We plan to use the next two weekdays to cut all of the extrusion that is needed to length and begin robot construction on Saturday.
As always, donât hesitate to reach out with any questions or comments!
Peter B
edit: added github link
. They assume that it will take roughly 2 weeks to test and tune everything.
