RD4B Without Bracing Through the Middle?

So I was brainstorming for this upcoming season, and a design I came up with required full movement through the middle of the bot. But since we need a RD4B to score on towers, I realized that I would need to brace the two towers. But is there any way to build a reliable lift that doesn’t require the middle bracing?

it’s probably possible if you have amazing build quality and did some really good lift pid, but I wouldn’t recommend it.

  1. Does it need to be a wide space, in which case the V5 motors used to power each side would present a problem.

  2. You could probably get away with bracing the upper part of the lower lifting bars of the DR4B presuming you don’t require a full 360 Degree+ rotation of whatever you are rotating through the lift.

I am trying to get a stack of cubes to go from tilted to upright through the center.

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I’m sure there are ways to do that w/o going through the center of your DR4B (te he he)

But who knows, you could be setting the meta.


We tried to do something like this in ITZ where we would pick up cones in behind the bot and stack them on the front of the bot. The issue is that each side will want to go up at it’s own, slightly different rate each time you move the arm. Thanks to compounding error, we bent axles like crazy that year. Although I’m not saying it can’t be done; we didn’t use high strength axles and we didn’t have overly-sophisticated code to combat our issues. I’d love to see it pulled off

Yea like @Xenon27 said, a good lift PID could fix that issue. But I might experiment with the high strength axles as well.

I just wouldn’t if I were you. My auto-stabilizing PID worked really well in my opinion but it should be secondary to great mechanical bracing. It will simply just work better than any PID or software stabilization.

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imo build a good 6 or 8 bar lift instead of a dr4b. this generally has better balance.
you could also go for a cascade lift. build one that lifts from the side and is clear thru the middle.

Well… you can do w/o a brace. But like what many others have mentioned - i wouldnt recommend it.

Even my teams will struggle to get a real good build w/o a brace (and i do consider my teams having at least above average quality of build).

How abt just doing an one-arm bandit? Do you need both sides of the dr4b?