Team 254 Presents: Backlash Technical Binder 2019

Team 254 is pleased to present the Technical Binder for our 2019 robot: Backlash. Please feel free to ask any questions you might have.

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How hard was it to implement a succ climb into the robot after it was already fully built or was adding a succ climb planned ahead of time?

Why did you opt for a single stage elevator and an arm instead of just a two stage elevator?

How do you prevent load from being put on your cylinder even though it is retractable on your climber?

It says in the binder that you used 7.25 OD x 6.5 ID bearings for the turret, where did you buy them from and how much were they? Just a quick check on McMaster for references and they are 700+ dollars, which would not be allowed by the rules (and impractical for budgeting)

Field-relative positioning through non-linear state estimation

:white_check_mark:

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Do you ever see going back to Colsons in the middle? Not counting games like 2016.

Why the switch back away from mag encoders on drive?

Was there any damage to the thin wall tube on the arm?

Why dog shifter over ball shifter for the drive?

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I’ve heard that top teams refrain from using colson because they slip in auton or something and so auton is less accurate.

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254 and a few other teams have noticed differing odometry depending on the direction of robot travel relative to the carpet grain with colson wheels. It was significant enough to warrant swapping back to treaded wheels.

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I know that part, and I remember Jared’s post from when he first wrote it. I was just curious if it was something that would become their new standard. Other than the added cost the only instance I could think of would be a field that was majority HDPE.

How does the bearing setup in the old stinger climber work it almost looks like their are ball bearings arranged around the outer tube.

To anyone: Blue nitrile vs colson in detail

Brake system- how did it work?

So the way 254 does it is that they use an over-centering linkage which hits a stop slightly before the piston hits the end of its travel. You can see more details in this post here.

Was the acceleration gains from two speeds with neos worth it looking back on the season? Why not chain in tube for the drivetrain?

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Has 254 ever done chain in tube?

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yes i believe in 2015.

I’m curious about the suction climb and what happens after the match ends. I know there’s a ratchet so it doesn’t fall down, but that still requires a vacuum seal on the platform to work. When the robot is disabled the vacuum pump is no longer running. How do you maintain that seal for extended periods of time even after the match has ended? Is there some sort of tank to extend the volume of the seal? Or does the pad work on it’s own? Is there some sort of safety mechanism on the chance it does end up falling down? How long could it theoretically stay suspended on the platform?

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They use a check valve. It allows air to be pulled out but not let back in.