pic: 2910 CAD Release 2018

swerve
cad
frc2910
2018

#1



Team 2910 Jack in the Bot is excited to release the CAD for our 2018 robot Kayla.

Parasolid:
FRC 2910, 2018 TopLevel Robot.x_t

STEP:
FRC 2910, 2018 TopLevel Robot.STEP


#2

Thank you for releasing your CAD this is great.


#3

First of all I will say I loved robot and swerve design. Second I am wondering which program and settings you used to get such a great render. I can’t wait to check out your robot design.

Mads Eskildsen


#4

In general, our team uses SolidWorks to CAD, and I used the Photoview 360 add-on to generate the render. The reason it is so high quality is because it is at a resolution of 8k. I trimmed it to be square, but the original aspect ratio was 7680:4320. This is a 16:9 ratio for use as a computer background and the like.


#5

This is super cool! I love your guys’ robot, especially those awesome swerve modules. I have a few questions about your robot.

Is the second pancake piston (towards the middle of the robot) in the elevator gearbox being used for braking the elevator?

Also, what is the purpose of the two free spinning wheels at the base of the elevator? I would assume cushioning for the cube but the shaft crossbars of the carriage seem to go out a bit farther.


#6

Thank you!

Yes, we have one cylinder for shifting speeds (high gear for cube placement and low gear for climbing), and one for locking the elevator after we’ve climbed.

The two wheels are custom water-jetted so that we don’t bottom out when we are going sideways over the platform. We do occasionally get stuck, but these wheels stop that from happening a lot more.


#7

Thanks for the quick response.

Those wheels are pretty clever. What material are they made out of?


#8

They’re just 6061-T6 aluminum.


#9

Thanks for the response, my team uses inventor pro and as a cadder I’ve always wanted to try solid works. The renders look great and I hope to create cad models and renders as good as yours in this coming season.


#10

Thanks for sharing this.
I saw all of the Einstein matches from the field area.
This robot’s performance was the 2nd best robot next to 254, IMO.

I had never heard of this team, until many of us watching noticed how awesome this robot performed. Not surprised at all this alliance only lost to the eventual winners in the playoffs.


#11

Something that’s immediately catching my eye is how you ran your belt for your elevator. Why did you choose to use this belt-in-tube approach over something more traditional, like a spool and winch? Packaging? How was assembly with this complicated belt run?


#12

I love the swerve design, great to see an off-season module being used the very next year which made this robot even better.
I have a question about the module though, what kind of bearring is being used? It looks like some sort of a lazy susan bearring to me?


#13

We really liked how the packaging working out with the belt, but I suppose a string could have been routed in a similar fashion. It is out of the way and mostly hidden were it wont get caught on stuff. We had people come to our pit quiet a few times to find out how our elevator was moving because it isn’t immediately obvious. One nice thing about using belt is that you don’t need to worry about where it is tracking on a spool. As for how we ended up with the belt. It was just sort of the first way we designed to drive the elevator in CAD. Everything seemed like it would work so we built it.

The assembly is not particularly difficult, it just takes some time. It is easiest if you temporarily remove a few of the elevator guide bearings and separate the stages of the elevator. Then it’s just feeding the end of the belt through the tubes and around the bearing pulleys and making sure it is not twisted. The whole process of replacing a broken belt would take about around 45 minutes. We broke a fiberglass tensile cord belt during build season by running into our hard stops and cutting through it with a sharp edge where it was fixed to the carriage. After that we removed the sharp edge from the design and switched to a steel tensile cord belt and it has held up since.


#14

Thank You, We were quite excited on kick off day to find that the game was swerve friendly.

The bearings we used are thin section X-contact bearings. I am selling them here swervedrivespecialties.com/products/bearing-3-5id-x-4od.


#15

Hey Guys! How do you zero your encoders on the swerve azimuth before each match? Thanks.


#16

I didn’t design this swerve, but I hope I can explain how their azimuth encoders work. They’re using the US Digital MA-3 Absolute Encoders, which report an absolute position that is maintained even when the robot is powered off. Usually, we’d want to put the absolute encoder directly on the object that’s rotating, but that’s not possible in this case. To work around this, 2910 uses a separate gear reduction to the encoder that matches the gear reduction from the VP to the wheel rotation, so the encoder is effectively 1:1 with the wheel.

Since their absolute encoder always “knows” where it is, and it’s 1:1 with the wheel, they never have to zero their encoders on their azimuth.

I hope this helped!
Aaron


#17

Yeah, that helps. Thanks!


#18

We use absolute encoders from AndyMark. They retain the position of the modules after every match, so we should never have to zero.

Encoders can be found here: https://www.andymark.com/MA3-A10-250-N-absolute-encoder-p/am-2899.htm


#19

Yep, exactly right! I didn’t see your response at first.


#21

Amazing robot! It was so awesome watching you guys skid across the field on Einstein in no time

I have one question though - am I missing something or there isn’t an encoder on no driving motor / axle on none of the serve modules?