Welcome to 5417’s first build thread! We are joining the #openalliance. We have been running for 7 years out of Allen High School, first at the main campus and recently in the last few years, we moved to the Steam Center.
We will be competing at Week 1 Waco and Week 4 Irving, hope to see y’all there!
Unfortunately we had run into a bit of issue in updating our build thread for our first two weeks so we will be running a quick rundown of events that occurred our first two weeks.
Week of Kickoff (Week 1)
This week we started off the season with our tools training for newcomers and safety training. Our build team is then split off into various groups to create prototypes and develop ideas that was thought up. We approach prototyping by looking for two things out of each concept, the magic numbers, and the proof of concept. Every prototype has a purpose, we prototype only to prove that such idea is possible and can be converted to an actual mechanism. As well as to obtain to magic numbers for creation of a mock up/semi realistic mechanism.
Intestine is the wording we uses for the part from the point where the ball exits the intake into the robot to the point where it exits into the shooter. The reason we combined the two mechanisms this year is because we realized that it was much easier to incorporate and have been arrangement for robot real estate (arranging for which mechanism gets which part of the robot) if the intake and intestine is streamlined into a single sub team and have better discussions with one another.
As soon as our game discussion was over, we brought out the handy dandy swerve everybot that we build during the offseason last year and modified the intake to fit the balls this year. This was done to test for the magic numbers of what height and width outside the bumper is the first contact point best at, and what compression value works the best when intaking.
We came to the conclusion that an 1.5"-2" compression works extremely well in intaking.
The material that we used in the gif above was simply pool noodle cut open and warped around a 1" tubing. This allowed us to wrap various materials around it such as different types of tape and other friction wrappings. Our finding was that this season’s ball was not picky on what type of material to intake with.
We first listed out what we want on our shooter and what choices that we have to make.
- Adjustable vs Non-adjustable hood
- Turret vs aiming by turning
These choices were left up to discussion and nothing much were really decided for the whole of week 1, we mainly prototyped various shooters and looked at advantages of one versus the other in both practical situations and theoretical situations.
Due to this year’s game being a vertical goal, we had a interesting idea of implementing a double wheel shooter that’s flat facing straight up with two wheels facing opposite of each other. We can then change the trajectory of the ball path by having one wheel spin faster than the other, thus creating a curve towards the slower wheel. While this was a interesting concept to play with in theory, we soon discovered that in practice, it was simply to little change in the angle to affect the trajectory enough to be useful.
We also messed around with a standard non-adjustable hood and found that it is as reliable as always.
After thriving the last two year off our climber (the mechanism that outlived everything else), we were pretty confident with our climbing game. So as soon as we started, we aimed for that sweet 15 points traversal climb.
The first week was mainly theoretical discussions involved with many white boards and expos, we took huge inspiration from 3572 from their 2013 climb since it was extremely similar to our old climb and we didn’t have to change much from it. But after doing some math and theoretical situations and looking at past climbs, we realized that we could make the whole process faster by having box tube like arms like ttb climber instead instead of pull up like arms and also ensure that we never reach outside of the horizontal 16" limit from the bumper.
FRC 3572 30 point climber - YouTube
Drivetrain, the one topic that will never have clear answers.
The first question in discussion for us was the topic of discussion for the past 3 years. Swerve or west coast drive(wcd). We felt that this year was one of the years where you can argue that swerve might be really oppressive, that alongside the fact that we were able to run a custom design swerve bot during last off season, it was looking more and more like a swerve season. But we after much discussions, we resorted back to wcd because of the a few reasons:
- we never ran a COT swerve prior to the season and only ran a custom swerve designed by one of the design leads
- we felt that we had perfected the wcd drivetrains to a level where it is extremely competitive with a really well practice driver.
- To add on to 2, we are also planning on making a practice bot this year to play one on one defense with the competition bot, so running swerve might cut too much dent in our budget that we can’t go forward with this plan.
The second question was gearbox, after years of running cims, we had successfully swapped over the neos and quickly decided on a 6 neo drivetrain. We then thought about the theoretical speeds that we would like to reach in our drivetrain, last year we ran a 12 fps gearbox and it worked extremely well with its ability to push robots and traveling quickly around town. We felt that we might want to be a little bit faster this year in terms of acceleration to improve our cycle time, we settled for a theoretical speed of around 15-17 fps. With 3 neos on each side, this drivetrain will be the fastest and most pushing power will have ever had.
This week we started wrapping up prototyping various ideas and started thinning down to 1 or 2 ideas for each mechanism. This way we can jump into week 3 finalizing plans and proceed with integration and final designs. This will ensure that we are on schedule to deliver a “final” cad on 12:00 PM 1/30/2022
This week we had many extremely successful prototypes, we first tested one of our favorite intake material, the Entrapption star! This was used first in our 2019 robot for the intake of the cargo and it was really fun for us to mess around with.
We then tested out the regular materials such as the compliant wheels.
We settled on the Entrapption star but did not have enough to create a final prototype for us to incorporate so that we can test the flow of the balls into the intestine. So we settled with the compliant wheels for now.
Next we moved onto the intestine. After reading through many build threads regarding singulation of the balls, we concluded that we want to have constant contact of the balls at any point and we don’t need to worry much about singulation jams that would often occur in infinite recharge as the balls are much less compressible. We tested out having rollers spaced apart with small omni wheels on them as our constant active contact to the balls forcing them into our hopper and it worked extremely well.
There was not much going on in the shooter team in terms of practical testing but we were able to get many of the questions that were left unanswered in week 1 solved through a lot of theoretical debates.
- Adjustable hood vs Non-adjustable hood
After looking at Cavbot 7492’s update on their field and shooter testing, they have found out that balls shooting from far bounces out extremely easily. We concluded that any shots farther than from the safe zone is invaluable for us to attempt as it will result in frequent bounce outs, so the incentive for running adjustable hood became a lot less. Another topic that came in discussion is the impact angle, if we ran an adjustable hood, we shoot at different distance from the goal by changing the arc, so if we shoot from medium range using the adjustable hood, our intake angle will be much more perpendicular to the faces of the cone of the upper goal. While on the other hand, if we have a non-adjustable hood, this allow us to have more practice time rather than perfecting a adjustable hood, and it will also less the angle of impact and in theory will stay in more often.
*Turret vs aiming by turning
Last year, we aimed by turning the entire robot and it did make us a lot easier to defend against as a slight tap would disrupt our shooter by a lot, so this year, we felt that a turret would definitely be desirable even if it might take practice time off our hands.
We were able to develop a prototype of the climber designed, it was partially completed today but I was unable to get pictures. We will be testing the prototype next week so I’ll just create a separate update for climbers next Tuesday when the testing data is out.
One thing that was left undiscussed last week was the topic of frame perimeter, which ended up being a huge discussion. We realized that we want to create a robot that’s small so that we will be able to slither our ways our of defense and won’t take up an extreme amount of space when we are climbing, but we always want a decently long robot so that we don’t exceed the 16" inch horizontal extension rule when we climb. So we waited until pretty much every other mechanism was thinned down to a single idea and created our drive train base off the needs of everyone else while maintaining the smallest perimeter possible. We wished to have the possibility to intake in two balls at once so the width has to be at least 20 inches, and due to our intestine design and climber tilt, we settled for the dimension of 25"x30" for the robot dimension.